Revista de Ciências Agrárias

Soil diversity and soil properties limiting agricultural use in semi-arid landscapes of Israel

Abstract The semi-arid zone of the Mediterranean region is characterized by high spatial diversity of natural resources and its value for agriculture purposes. In Israel, desalination processes and wastewater treatments development allow a significant expansion of irrigated territories and the incorporation of new subtropical crops which demand high amount of irrigation water. This situation requires a suitability assessment of soils that were previously under dryland farming practices. For this purpose, a soil-landscape study was carried out in the Northwestern Negev region, considering environmental factors, aerial photographs of different years, detailed soil maps, morphological descriptions, and chemical data of selected soil profiles. The study revealed 8 soil types typical of the region, which allowed to characterize the soil diversity of the study area and link it to soil properties (14) that limit agricultural uses. The suggested criteria could be considered as a tool for land use planning which seeks to transform marginal lands into suitable lands for intensive agricultural purposes.

Resumen La zona semiárida de la región mediterránea se caracteriza por una gran diversidad espacial de recursos naturales y su valor para fines agrícolas. En Israel, el desarrollo de procesos de desalinización y tratamiento de aguas residuales permiten la expansión de territorios agrícolas irrigados y la incorporación de nuevos cultivos subtropicales los cuales demandan grandes cantidades de agua de riego. Esta situación requiere una evaluación de la aptitud de suelos usados previamente en actividades agrícolas de secano. Con este propósito, se realizó un estudio de suelo y paisaje en la región del Noroeste del Negev, considerando factores ambientales, fotografías aéreas de diferentes años, mapas de suelo detallados, descripciones morfológicas y datos químicos de perfiles de suelo. El estudio reveló 8 tipos de suelo típicos de la región, lo que permitió caracterizar la diversidad de suelos del área de estudio y vincularla a las propiedades del suelo (14) que limitan su uso agrícola. Los criterios sugeridos podrían ser considerados como una herramienta para la planificación del territorio con fines de transformación de tierras marginales en tierras aptas para la agricultura intensiva.

Evaluation of controlled burning conditions that influence the physical and chemical attributes of soils under Echinospartum horridum

Resumen Con el objetivo de evaluar los efectos en el suelo de distintas severidades de quema, se han realizado quemas controladas de monolitos de suelo bajo distintas temperaturas y tiempos. Los monolitos han sido muestreados justo después de las quemas y tras cinco meses de conservación en invernadero, separando las capas de 0-1 y 1-3 cm. Se han medido atributos físicos (persistencia de la repelencia al agua) y atributos biológicos (carbono orgánico, lábil, recalcitrante, intermedio, microbiano y respirado). Los resultados indican que las quemas de mayor severidad causan sobre la materia orgánica un fuerte impacto tanto a nivel cuantitativo como cualitativo, afectando a diversas fracciones del carbono orgánico, así como a la biomasa microbiana y su actividad. Las quemas de mayor severidad también causan una fuerte repelencia al agua en superficie o profundidad, en función de la duración de la quema. A los cinco meses, la mayoría de los parámetros han vuelto a valores iniciales, y ha desaparecido la hidrofobicidad post fuego, lo que sugiere una rápida recuperación del suelo frente a la perturbación causada por el fuego.

Abstract With the objective of evaluating the effects of fire on soil of varying burning severity, experimental burnings of soil samples under different burning temperatures and times have been conducted. Burned soil monoliths have been sampled immediately after burning and five months after greenhouse conservation, separating layers of 0-1 and 1-3 cm depth. The impact of different burning severities was assessed based on the change of physical attributes (persistency of water repellency) and biological attributes (labile, intermediate, recalcitrant, microbial, and respired organic carbon). The results show that the most severe burns cause a big impact on organic matter, both on quantitative and qualitative levels, affecting the diverse organic carbon fractions, as well as the microbial biomass and activity. Most severe burns also cause a big water repellence on the 0-1 or in the 1-3 layers, depending on burning severity. After five months, most of the assessed parameters have been returned to initial levels and post-fire water repellence have disappeared, suggesting a fast recovery of the soil properties after the disturbance caused by the burnings.

Application of electromagnetic induction and inversion modelling for 3D mapping of soil texture

Abstract Using a DUALEM21 sensor, we conducted electromagnetic induction (EMI) surveys in an agricultural field in the Roxo irrigation perimeter in Alentejo, Portugal, to evaluate the potential of using this technique for 3D mapping of soil texture. We first processed apparent electrical conductivity data (ECa) and then used a Quasi-3D inversion algorithm in order to obtain 3D electromagnetic conductivity images (EMCI) of the actual bulk soil electrical conductivity (EC). This is because the ECa is a depth-weighted, average conductivity measurement and does not represent the actual EC variation with depth. Afterward, we evaluated the possibility of establishing a linear regression (LR) relationship between EC and soil texture collected from 13 soil sample locations at 3 layers to a depth of 0.60 m. We selected the locations for soil sampling based on the ECa variations. Our analysis showed that it is possible to establish a relatively good LR between EC and clay, and between EC and sand (R2>0.60), allowing us to convert EMCI into sand and clay content and generate sand and clay 3D maps down to 0.60 m depth.

Resumo Neste estudo, foi feito um ensaio num campo agrícola inserido no perímetro de rega do Roxo, no Alentejo, usando o sensor de indução eletromagnética DUALEM21, de forma a analisar o seu potencial no mapeamento 3D da textura do solo. Os dados da condutividade elétrica aparente do solo (ECa), obtidos com o sensor, foram transformados utilizando um algoritmo de modelação inversa, Quasi-3D, para obter imagens da condutividade elétrica (EMCI) 3D da condutividade elétrica do solo (EC). Esta transformação é necessária, uma vez que ECa representa uma medição média, ponderada em profundidade, da EC e não a sua verdadeira variação com a profundidade. Analisou-se a relação linear entre a EC e a textura do solo, usando dados recolhidos em 13 pontos de amostragem, selecionados tendo em conta a variabilidade da ECa. Em cada ponto de amostragem foram colhidas amostras em três camadas até à profundidade de 0.6 m. Os resultados mostram que existe correlação significativa entre EC e a fração argila e entre EC e a fração areia (R2>0.6), sendo possível transformar as EMCI em mapas 3D do teor de argila e do teor de areia, até uma profundidade de 0.6 m.

Salinity monitoring in reclaimed marsh soils with electromagnetic induction tomography and and NDVI imagery

Resumen La interacción entre la capa freática salina y somera y la agricultura intensiva da lugar a un frágil equilibrio entre la acumulación y lixiviación de sales en los suelos de marisma recuperada del sector de riego B-XII, en el suroeste de España. Evaluamos el potencial de la tomografía de inducción electromagnética (EMI) e imágenes de NDVI de Sentinel 2 para el seguimiento de la salinidad del suelo a escala de parcela en esta zona, usando mediciones de la conductividad eléctrica aparente (ECa) del suelo realizadas en 2017 y 2020. Las estimaciones de la conductividad eléctrica (EC) obtenidas mediante inversión de la ECa mostraron una fuerte correlación (R≈0,90) con la conductividad del extracto de pasta saturada (ECe) y la relación de absorción de sodio (SAR), lo que dio lugar a ecuaciones de calibración lineales con R2≈0,80 para ambos años y resultados de validación cruzada de exclusión (LOOCV) fiables para los horizontes subsuperficiales de 0,55 < R2 < 0,81. El patrón espacial de EC mostró correlación inversa con el del NDVI para tomate para industria, algodón y remolacha cultivados entre los años 2017 y 2019, alcanzando valores R de -0,64, -0,87 y -0,73, respectivamente.

Abstract The presence of a shallow saline water table in combination with intensive agriculture in the reclaimed marshes of the B-XII irrigation district, in SW Spain, may disrupt the fragile balance between salt accumulation and leaching in the root zone. We evaluate the potential of electromagnetic induction tomography (EMI) and the use of Sentinel 2 NDVI imagery for field-scale soil salinity monitoring using soil apparent electrical conductivity (ECa) measured in 2017 and 2020. Depth-specific electrical conductivity (EC), obtained from the inversion of ECa, showed a strong correlation (R≈0.90) with laboratory-analysed saturated paste extract conductivity (ECe) and sodium adsorption ratio (SAR), resulting in linear calibration equations with R2≈0.80 for both years and reliable cross-validation of exclusion (LOOCV) results for the subsoil (0.55 < R2 < 0.81). The spatial pattern of EC showed inverse correlation with NDVI for processed tomato, cotton and sugar beet, cropped between 2017 and 2019, reaching R values of -0.64, -0.87 and -0.73, respectively.

Vegetation indices and climatic variables for the evaluation of ecosystem services as a model for the management of protected natural areas

Resumen Garantizar y promover la sostenibilidad ambiental es uno de los principales objetivos de la Agenda 2030 para el Desarrollo Sostenible. Sin embargo, factores tales como actividades extractivas, culturales e incluso el cambio climático, resultan las principales causas de presión que determinan el estado en que se encuentra el territorio. Es importante disponer de herramientas que nos informen sobre el grado de consecución de los objetivos planteados, así como en la identificación de los impactos y sus consecuencias para así poder realizar una gestión que mantenga o incremente la biodiversidad y demás recursos del área. En un área protegida del suroeste de la península Ibérica, en la que tuvo lugar una importante actividad minera, hemos analizado la variación de un índice de vegetación (NDVI) y las variaciones climáticas como herramientas para una gestión sostenible. Los resultados muestran el impacto que la actividad extractiva y las variaciones climáticas han ocasionado en los recursos y por tanto, en los servicios ecosistémicos asociados al territorio. Las herramientas propuestas se han mostrado rápidas y precisas para la toma de decisiones y su aplicación en otras áreas puede servir de modelo para la consecución de los objetivos de la Agenda 2030.

Abstract Ensuring and promoting environmental sustainability is one of the main objectives of the 2030 Agenda for Sustainable Development. However, factors such as extractive and cultural activities and even climate change are the main causes of pressure that determine the state of the territory. It is important to have tools that inform us about the degree of achievement of the objectives set, as well as the identification of impacts and their consequences to be able to carry out a management that maintains or increases the biodiversity and other resources of the area. In a protected area in the southwest of the Iberian Peninsula, where an important mining activity took place, we have analyzed the variation of a vegetation index (NDVI), climatic variations and the state of soils in a protected area in the southwest of the Iberian Peninsula as tools for sustainable management. The results show the impact that extractive activity and climatic variations have on the affected resources and therefore on the ecosystem services associated with the territory. The proposed tools have been shown to be fast and accurate for decision making and their application in other areas can serve as a model for achieving the objectives of the 2030 Agenda.

Study of the influence of soil use on the relationships between physical-chemical variables through network analysis

Resumen El ser humano al emplear el suelo modifica paulatinamente sus propiedades lo que puede producir la pérdida o reducción de la salud del suelo. El objetivo de este trabajo fue analizar si diferentes usos del suelo producen diferencias en las relaciones de un set de 24 variables físico-químicas. La zona de estudio se situó al sureste de Madrid (España) en la que se muestrearon 10 puntos en los que los tres usos principales del suelo (cereal, olivar y natural) se encontraban colindantes. Las relaciones entre las variables físico-químicas para cada uso se determinaron por las correlaciones bivariadas de Spearman (P<0,05). El estudio de estas relaciones se llevó a cabo mediante técnicas de análisis de redes. El uso del suelo influyó en las relaciones entre las variables analizadas. Los suelos agrícolas, especialmente los de cereal, tuvieron una menor y peor cantidad de correlaciones. Los suelos agrícolas tuvieron una mayor tendencia a formar módulos independientes entre sí, lo que indicaría una menor resiliencia de estos suelos. Las variables físico-químicas más importantes cambiaron entre usos: relacionadas con la materia orgánica en la red del uso natural y relacionadas con distintos coloides inorgánicos en los usos agrícolas.

Abstract The human being when using the soil gradually modifies its properties which can cause the loss or reduction of the health of the soil. The objective of this work was to analyse whether different land uses produce differences in the relationships of a set of 24 physical-chemical variables. The study area was located southeast of Madrid (Spain) in which 10 points were sampled where the three main soil uses (cereal, olive grove and natural) were adjacent. The relationships between the physical-chemical variables for each use were determined by Spearman's bivariate correlations (P<0.05). The study of these relationships was carried out using network analysis techniques. Soil use influenced the relationships between the variables analysed. Agricultural soils, especially cereal soils, had fewer and worse number of correlations. Agricultural soils had a greater tendency to form modules independent of each other, which would indicate a lower resilience of these soils. The most important physical-chemical variables changed between uses: related to organic matter in the network of natural use and related to different inorganic colloids in agricultural uses.

Assessing soil salinity with electrical conductivity and NDVI in the B-XII irrigation district, Lebrija (Sevilla)

Resumen Se propone una metodología para estimar la salinidad del suelo y su relación con el NDVI a escala de parcela. Se midió la conductividad eléctrica aparente del suelo (CEa) con un sensor de inducción electromagnética (IEM) en una parcela del sector B-XII, Lebrija (Sevilla) y se obtuvieron imágenes bi- y tridimensionales de la conductividad eléctrica (CE) mediante inversión. La CE mostró buenas relaciones con los indicadores de salinidad del suelo (R2>70%), lo que permitió la estimación de dichos indicadores a partir de las imágenes de CE. Se evalúa la metodología y los resultados que arroja usando series históricas de 7 años de imágenes de NDVI y realizando de esta forma un seguimiento del efecto de la salinidad del suelo sobre el desarrollo de los cultivos. La identificación de zonas de salinización puntual con efectos negativos sobre el desarrollo de los cultivos permite apoyar la toma de decisiones en cuanto al manejo de suelo, agua y cultivo.

Abstract A method is proposed to estimate soil salinity and its relationship with NDVI at the plot scale. Soil apparent electrical conductivity (ECa) was measured with an electromagnetic induction sensor (EMI) at a commercial plot in the B-XII irrigation district, Lebrija (Seville). Bi- and three-dimensional images of soil electrical conductivity (EC) were obtained using inversion. Estimated EC showed strong relationships with soil salinity indicators (R2>70%), allowing the estimation of these indicators from the EC images. The methodology and the obtained results were evaluated using historical NDVI imagery obtained during 7 cropping seasons and allowed us to monitor the effect of soil salinity on crop development. The identification of areas where sudden soil salinization occurs, with negative effects on crop development, is relevant for informing soil, water and the crop management decision-making.

Study of microbial communities in Lusitanian organic and conventional agricultural soils by phospholipid fatty acid analysis

Resumen La comunidad microbiana de un suelo está condicionada por las condiciones del suelo y por el tipo de manejo que se hace del mismo. En este estudio se han analizado, mediante análisis de ácidos grasos fosfolípidos (PLFAs), las comunidades microbianas de varios suelos agrícolas, de la zona pedoclimática lusitana, bajo dos tipos de sistemas: convencional y orgánico. Los suelos orgánicos presentaron una mayor cantidad de PLFAs totales y asociados a bacterias y a hongos arbusculares micorrízicos. Observamos que las cantidades de estos ácidos grasos estaban relacionados con la cantidad de materia orgánica y de nitrógeno total del suelo. Por otro lado, en los suelos convencionales encontramos una mayor cantidad de ácidos grasos relacionados con ascomicetos y basidiomicetos y una mayor proporción hongos/bacterias. Esto está directamente correlacionado con una mayor proporción de macro-agregados (> 2 cm) e inversamente correlacionado con la cantidad de nitrógeno.

Abstract The microbial community of a soil is determined by the soil properties and by the type of soil management. In this study, the microbial communities of several agricultural soils in the Lusitanian pedoclimatic zone, under two management systems (conventional and organic), were characterized by phospholipid fatty acids (PLFAs) analysis. Organic soils showed a higher amount of total PLFAs and PLFAs associated with bacteria and arbuscular mycorrhizal fungi. We observed that the amounts of these fatty acids were related to the amount of soil organic matter and total nitrogen. On the other hand, in conventional soils we found a higher amount of fatty acids related to ascomycetes and basidiomycetes and a higher fungi/bacteria ratio. This is directly correlated with a higher proportion of macro-aggregates (> 2 cm) and inversely correlated with the amount of nitrogen.

Edaphic Characteristics of Olive-growing Areas in Northeast Portugal: an approach based on soil and land use maps

Resumo A oliveira é atualmente a cultura que ocupa a maior superfície agrícola em Portugal e a exploração dos seus frutos reveste-se de grande importância socioeconómica. Existe pouca informação disponível sobre as condições edáficas em áreas cultivadas com olivais no Nordeste de Portugal e como elas exercem influência na distribuição e desenvolvimento da cultura. Dessa forma, este estudo visa contribuir com a atualização da informação existente através da identificação das principais características edafoclimáticas das áreas olivícolas na Região. A informação de base para o estudo incluiu como fontes principais a Carta dos Solos e da Aptidão da Terra do NE Portugal, a Carta de Uso e Ocupação do Solo e a Carta Administrativa Oficial de Portugal. O olival cobre aproximadamente 105 mil ha no NE de Portugal e é a cultura que ocupa a maior área agrícola da Região. Os solos sob olivais são geralmente pouco profundos, pedregosos, ácidos e pobres em matéria orgânica, grande parte situando-se em terrenos declivosos. As oliveiras estão bem-adaptadas aos condicionalismos edafoclimáticos regionais, mas é necessário implementar práticas alternativas que promovam uma melhor gestão dos pomares, para o que é importante aprofundar o conhecimento dos solos das áreas de olival.

Abstract The olive tree is currently the crop that occupies the largest agricultural area in Portugal and the exploitation of its fruits is of great socio-economic importance. There is little information available on edaphic conditions in areas cultivated with olive groves in Northeast Portugal and how they influence the distribution and development of the crop. Thus, this study aims to contribute to the updating of existing information through the identification of the main soil and climate characteristics of the olive growing areas in the Region. The basic information for the study included as main sources the Land Aptitude Charter of NE Portugal, the Land Use and Occupation Charter and the Official Administrative Charter of Portugal. The olive grove covers approximately 105 thousand ha in NE Portugal and is the crop that occupies the largest agricultural area in the Region. Soils under olive groves are generally shallow, stony, acidic and poor in organic matter, most of which are located on sloping terrain. Olive trees are well adapted to regional soil and climate conditions, but it is necessary to implement alternative practices that promote better management of orchards, for which it is important to deepen knowledge of the soils of olive groves.

Edaphic diversity in vineyards at Montesa and Torresalas (DOP Somontano, NE-Spain)

Resumen En este trabajo se caracterizan, clasifican y evalúan los suelos de dos zonas próximas a Barbastro (Montesa y Torresalas), en la Denominación de Origen Protegida Somontano (NE-España). Bajo un régimen de humedad xérico, las propiedades y formación de los suelos están íntimamente relacionadas con su posición en el relieve y, especialmente con su material parental. En Montesa, sobre margas y areniscas Oligo-Miocenas predominan los Calcisols, con Cambisols en unidades geomorfológicas menos estables. En Torresalas se encuentran Gypsisols sobre yesos Oligo-Eocenos y Calcisols sobre depósitos detríticos de terraza aluvial Pleistocena. Respecto a la aptitud para el cultivo de la viña, en Montesa se obtienen unos homogéneos índices de Potencial de Vigor (fuerte) y de Potencial de Precocidad (moderadamente débil) del terreno. En Torresalas, ambos indices muestran mayor heterogenidad, con un potencial de vigor que varía entre débil y fuerte, y un potencial de precocidad que varía entre moderadamente débil y moderadamente fuerte. Las variedades blancas (Gewürztraminer, Chardonnay) adquieren una elevada mineralidad sobre Gypsisols, lo que confiere a los vinos una peculiar personalidad. Las variedades tintas prefieren cultivarse sobre el resto de grupos de suelos, muy carbonatados, donde los vinos adquieren taninos de calidad y en un nivel adecuado.

Abstract Soils are characterized, classified and evaluated in two areas near Barbastro (Montesa and Torresalas), in the Somontano Protected Designation of Origin (NE-Spain). Under a xeric humidity regime, the properties and formation of the soils are closely related to their position in the relief and, especially, to their parent material. In Montesa, on Oligo-Miocene marls and sandstones, Calcisols predominate, with occasional Cambisols in less stable geomorphological units. In Torresalas there are two very different zones, with Gypsisols on Oligo-Eocene gypsum and Calcisols on detritic deposits of a Pleistocene alluvial terrace. Regarding the suitability for vineyard cultivation, in Montesa high values of the Vigor Potential index and moderately weak values of the Precocity Potential have been obtained. In Torresalas, both indices show greater heterogeneity, with Vigor Potential ranging from weak to strong, and Precocity Pontential ranging from moderately weak to moderately strong. The white varieties (Gewürztraminer, Chardonnay) acquire a high minerality on Gypsisols, which gives the wines a peculiar personality. The red varieties prefer to grow on the rest of the soil groups, very carbonated, where the wines acquire an adequate level of tannins and quality.

Application of different forms of organic matter in a pepper crop grown in soil

Resumen El objetivo de este trabajo fue comparar los efectos de dos fuentes de materia orgánica (compost de desmotadora de algodón y gallinaza) en un cultivo de pimiento (Capsicum annuum L. var.California) desarrollado en suelo. Se determinaron los efectos de estas enmiendas sobre la nutrición mienral de la planta de pimiento así como sobre la producción y contenidos minerales del fruto. Los resultados mostraron que la composición química de la materia orgánica aplicada al suelo influyó de forma diferente en el desarrollo del cultivo, destacando las plantas enmendadas con gallinaza las que mostraron mayores contenidos de macro y micronutrientes en hoja, así como en el fruto y mayor peso y número de pimientos recolectados. Posiblemente el mayor contenido en gallinaza que en el compost de algodón de péptidos de bajo peso molecular fácilmente asimilables por la planta, así como el mayor contenido de ácidos fúlvicos los cuales se degradan más fácilmente que los ácidos húmicos y por tanto, proporcionar nutrientes para la planta de forma más rápida sean responsables de estos resultados obtenidos.

Abstract The objective of this work was to compare the effects of two sources of organic matter (cotton gin compost and poultry manure) on a pepper crop (Capsicum annuum L. var. California) grown in soil. The effects of these amendments on the mineral nutrition of the pepper plant as well as on the production and mineral content of the fruit were determined. The results showed that the chemical composition of the organic matter applied to the soil had a different influence on the development of the crop, highlighting the plants amended with poultry manure, which showed higher contents of macro and micronutrients in the leaf, as well as in the fruit and higher weight. and number of peppers harvested. Possibly the higher content in poultry manure than in cotton compost of low molecular weight peptides easily assimilated by the plant, as well as the higher content of fulvic acids which are more easily degraded than humic acids and therefore provide nutrients for the plant faster are responsible for these results.

Mineralogy of fine earth and clays in a paleosol sequence on the island of Mallorca

Resumen Se estudia una secuencia de paleosuelos superpuestos desarrollados en el Cuaternario. Se han diferenciado 18 horizontes a lo largo del perfil del suelo con una profundidad de 12,5 m. Para cada horizonte se ha cuantificado el contenido mineral de la tierra fina (< 2 mm) y los minerales de arcilla correspondientes a la fracción <0,002 mm. Los filosilicatos constituyen los minerales mayoritarios de estos horizontes. Los carbonatos de calcio son también muy abundantes, pero con importantes diferencias entre horizontes desde horizontes descarbonatados a otros en que constituyen la fracción mayoritaria. El cuarzo, los feldespatos potásicos y las plagioclasas son otros componentes comunes. Las illitas constituyen el mineral de arcilla más común, presentandose en forma pura y formando interestratificados con esmectitas. Las cloritas y caolinitas son otras especies de arcillas presentes en todos los horizontes. La composición mineral del conjunto de horizontes de estos paleosuelos pone de manifiesto un origen común de los materiales que los constituyen.

Abstract A sequence of overlapping paleosols developed in the Quaternary is studied. Along a soil profile of 12.5 m have been differentiated eighteen horizons. For each horizon, the mineral content of the fine earth (< 2 mm) and the clay minerals corresponding to the <0.002 mm fraction have been quantified. The most common minerals of these horizons are phyllosilicates. Calcium carbonates are also very abundant, but with important differences between horizons, from decarbonated ones to others in which carbonates constitute the main fraction. Quartz, K-feldspars and plagioclases are other common components. Illites are the most common clay mineral, occurring in pure form and forming interstratified illite-smectite mixtures. Chlorites and kaolinites are other clay species present in all horizons. The mineral composition of the whole of horizons of these paleosols reveals a common origin of the materials that constitute them.

Processing of soil temperature data for computational simulations of an agroecosystem

Resumo Os serviços de ecossistema, como a limitação natural de pragas, incluem-se nas estratégias de gestão de agro-ecossistemas e o seu uso pode ser otimizado com base no conhecimento provindo da modelação computacional das pragas, dos seus predadores, e da paisagem. Neste artigo focamo-nos no processamento de dados de temperatura do solo, necessários para o funcionamento dos modelos de praga-predador Bactrocera oleae (mosca da azeitona) e Haplodrassus rufipes (aranha do solo) no olival. A metodologia de processamento permitiu-nos (1) completar as lacunas existentes na série de dados de temperatura do solo, recolhidos com periodicidade horária, (2) convertê-la numa série com periodicidade diária, e ainda (3) criar uma variável adicional, a temperatura média diária do solo durante o crepúsculo vespertino. Este último passo possibilita que não haja uma perda de informação no que diz respeito àquele período específico do dia, reduzindo-se o erro associado à desaquação da resolução temporal da variável climática média diária para exprimir um fenómeno que ocorre apenas durante um determinado número de horas do dia.

Abstract Ecosystem services, such as natural pest control, are included in agro-ecosystem management strategies and their use can be optimized based on knowledge from computational modelling of pests, predators, and landscape. In this article we focus on the processing of soil temperature data, necessary for the operation of the predator-pest models Bactrocera oleae (olive fly) and Haplodrassus rufipes (soil spider) in the olive grove. The processing methodology allowed us to (1) complete the gaps in the series of soil temperature data, collected on an hourly basis, (2) convert it into a series with daily periodicity, and (3) create an additional variable, the average daily temperature of the soil during the twilight. This last step prevents the loss of information regarding that specific period of the day, reducing the error associated with the deaquation of the temporal resolution of the average daily climatic variable to express a phenomenon that occurs only during a certain number of hours of the day.

The soils of Atlantic wet heathlands of Erica mackayana in N of Galicia

Resumen Los brezales son un tipo de hábitat con una estrecha y compleja relación entre las comunidades vegetales, dominadas por especies arbustivas de hoja perenne y unos suelos que se caracterizan por su pobreza en nutrientes y un elevado contenido en materia orgánica. Para caracterizar los suelos de los brezales húmedos atlánticos del norte de Galicia, dominados por la especie Erica mackayana, se estudiaron las propiedades físico-químicas y se caracterizó la materia orgánica en noventa parcelas de 18 sitios. El principal responsable de la nutrición de estos hábitats es una materia orgánica poco evolucionada a través de un intenso biorreciclado con un fuerte control local por condiciones microclimáticas y con poca relevancia de la naturaleza litológica. La capacidad de intercambio catiónico es baja y tiende a estar dominada por Al. En este contexto, el impacto del calentamiento climático y los cambios de uso del suelo sobre la evolución de la materia orgánica, así como la posibilidad de estabilización en compuestos organoalumínicos será el principal responsable de la evolución del sistema suelo-planta en este hábitat.

Abstract Heathlands are a habitat type with a close and complex relationship between plant communities dominated by evergreen shrub species and soils characterised by nutrient poverty and high organic matter content. To characterise the soils of the Atlantic wet heathlands of northern Galicia, dominated by the mackayana species, physico-chemical properties were studied and organic matter was characterised in ninety plots at 18 sites. The main responsible for the nutrition of these habitats is a poorly evolved organic matter through an intense biorecycling with a strong local control by microclimatic conditions and with little relevance of the lithological nature. Cation exchange capacity is low and tends to be saturated in Al. In this context, the impact of climate warming and land use changes on the evolution of organic matter, as well as the possibility of stabilisation in organoaluminic compounds will be mainly responsible for the evolution of the plant-soil system in this habitat.

Digital Soil Mapping of surface soil properties in El Órbigo and La Cepeda agricultural areas (León, NW Spain)

Resumen La escasez de información edafológica y cartografía tradicional ha desembocado en la búsqueda de nuevas técnicas que permitan solucionar esta problemática, de forma que se pueda obtener una cobertura completa y homogénea de la superficie. El objetivo principal de este trabajo es la elaboración de una cartografía de propiedades edáficas de interés como son materia orgánica, arena, limo y arcilla del suelo a través de la aplicación de la metodología Digital Soil Mapping en el área de Benavides de Órbigo (León). Para ello, se seleccionaron 75 muestreos de suelo ya existentes y distintas covariables ambientales relacionadas con los factores formadores del suelo. Con estas se llevó a cabo el análisis estadístico mediante la combinación de la regresión lineal múltiple y modelos lineales generalizados para obtener el mejor modelo de predicción para cada variable estudiada, además de los residuos generados por el modelo y la estimación del error. De todas las variables, el mejor valor de ajuste R2=0,55 y el error más bajo 2,145 se obtuvo con la materia orgánica, mientras que arena, limo y arcilla obtuvieron unos ajustes más limitados (0,368, 0,459 y 0,426, respectivamente). Por todo ello, se llegó a la conclusión de que, aunque el método es aplicable y útil, presenta todavía grandes limitaciones, por lo que es importante incidir en la búsqueda de soluciones que permitan obtener mejoras sustanciales en los resultados obtenidos.

Abstract The lack of soil information and soil maps has led into a search for new techniques to solve this problem, so that a complete and homogeneous coverage of the surface can be obtained. The main objective of this study is the mapping of edaphic properties of interest such as organic matter, sand, silt and clay through the application of the Digital Soil Mapping methodology in the area of Benavides de Órbigo (León). For this purpose, 75 existing soil sampling data and different environmental covariates related to soil-forming factors were selected. The statistical analysis was carried out through the combination of multiple linear regression and generalized linear models to obtain the best prediction model for each variable, in addition to the residuals generated by the model and the error estimation. Among all the variables, the best R2=0.55 fitting value and the lowest error 2.145 was obtained for organic matter; while sand, silt and clay reached more limited fitting values (0.368, 0.459 and 0.426, respectively). For this reason, it was concluded that, although the method is widely applicable and useful, it still has great limitations, so it is quite important to point out the search for solutions that allow to obtain considerable improvements in the results.

The use of Eucalyptus leaf biomass as biocide: effects on soil properties

Resumo A área florestal portuguesa é dominada principalmente por Eucalyptus globulus e, sendo esta uma espécie invasora e muito inflamável, é importante controlar a sua proliferação. Neste sentido, o projeto PEST(bio)CIDE, assentando numa perspetiva de economia circular, pretende explorar o potencial fitotóxico das folhas do eucalipto e utilizar a sua biomassa foliar como um biocida eficaz e ambientalmente seguro. Deste modo, é possivel associar um benefício económico a uma melhor gestão das áreas de eucalipto regeneradas após incêndio. Espera-se ainda que a introdução de biomassa no solo melhore a sua qualidade e a sua eficácia no aumento da reserva de carbono e na fertilidade do solo. Neste sentido, o presente trabalho foca-se na avaliação dos efeitos que a introdução da biomassa de eucalipto tem nas propriedades físico-químicas e biológicas do solo. Para isto, realizou-se uma experiência em microcosmos, em condições controladas, na qual se avaliou o efeito da adição de diferentes percentagens de folhas de eucalipto em algumas propriedades físico-químicas do solo e na atividade de enzimática da desidrogenase, ao longo do tempo.

Abstract The Portuguese forest area is mainly dominated by Eucalyptus globulus and, as this is an invasive and very flammable species, it is important to control its proliferation. In this sense, the PEST(bio)CIDE project, based on a circular economy perspective, aims to explore the phytotoxic potential of eucalyptus leaves and use its foliar biomass as an effective and environmentally safe biocide. In this way, it is possible to associate an economic benefit with a better management of the eucalyptus areas regenerated after fire. It is also expected that the introduction of biomass into the soil will improve its quality and its effectiveness in increasing the carbon stock and soil fertility. In this sense, the present work focuses on the evaluation of the effects that the introduction of eucalyptus biomass has on the physicochemical and biological properties of the soil. For this, an experiment was carried out in microcosms, under controlled conditions, in which the effect of the addition of different percentages of eucalyptus leaves on some physicochemical soil properties and on the dehydrogenase enzymatic activity over time was evaluated.

Spatial and temporal discrimination of soil attributes through multivariate statistical analysis: A case study in irrigated annual crops in South Portugal

Resumo Efetuou-se o estudo da variabilidade temporal e espacial de variáveis do solo, durante três anos em três parcelas agrícolas com culturas anuais regadas, em duas camadas (0-20 cm e 20-40 cm), recorrendo a Análise Fatorial (FA) e Análise Discriminante (DA). Com a FA agruparam-se os parâmetros observados num menor número de variáveis latentes relacionadas com atributos do solo. A DA foi usada para classificar e identificar os atributos mais influentes na discriminação no tempo e no espaço. A FA realizada para a camada superficial incluiu fatores relacionados com a textura, capacidade de retenção de água e nutrientes, composição química e fertilidade do solo. Na camada subsuperficial, a estrutura fatorial foi semelhante, com quatro fatores relacionados com a textura, composição química, disponibilidade de nutrientes e fertilidade do solo. Os fatores mais influentes na discriminação temporal (datas de amostragem) em ambas camadas foram os relacionados com a composição química. Quanto à diferenciação espacial (parcelas), o fator dominante na camada superficial foi a textura e na camada subsuperficial, a disponibilidade de nutrientes. Os resultados obtidos apresentam potencialidade para a identificação de indicadores de qualidade do solo ou para a avaliação multidimensional e integrada de padrões de variação temporal e espacial de funções do solo resultantes de práticas de gestão ou de processos de degradação.

Abstract A study of temporal and spatial variability of soil variables was carried out during three years, in three farm plots with irrigated annual crops, in two layers (0-20 cm and 20-40 cm), using Factor Analysis (FA) and Discriminant Analysis (DA). With FA, the observed parameters were grouped into a smaller number of latent variables related to soil attributes. DA was used to classify and identify the most influential attributes in time and space discrimination. The FA performed for the surface layer included factors related to texture, water and nutrient retention capacity, chemical composition, and soil fertility. In the subsurface layer, the factor structure was similar, with four factors related to texture, chemical composition, nutrient availability, and soil fertility. The most influential factors in temporal discrimination (sampling dates) in both layers were those related to chemical composition. As for the spatial differentiation (plots), the dominant factor in the surface layer was texture and in the sub-surface layer, the availability of nutrients. The results obtained show potential for the determination of soil quality indicators or for the multidimensional and integrated assessment of patterns of temporal and spatial variation of soil functions resulting from management practices or degradation processes.

Crop root cuantification in intensive sprinkler irrigation system

Resumen Este trabajo pretende cuantificar la distribución en profundidad del sistema radicular de los principales cultivos en riego por aspersión en el Valle medio del Ebro (España), para poder utilizar esta información en modelos de simulación de cultivos e hidrologicos. Se han muestreado cilindros de suelos en antesis de los cuatro cultivos principales de la zona: cebada, maíz, alfalfa y guisante, de los que se han extraído las raíces por lavado. En ningún cultivo se observaron raíces por debajo de 40cm y hasta esa profundidad la densidad del sistema radicular disminuye en profundidad claramente para maíz y alfalfa. Casi el 80% de las raíces se encuentran en los primeros 20cm del suelo, aunque la cebada ha mostrado una distribución más homogénea en profundidad. Para todo el perfil del suelo, se han encontrado más raíces en este trabajo que en estudios previos, sobre todo para cebada y maíz debido a la intensificación del cultivo en regadío. Sin embargo, los cultivos de leguminosas en suelos de textura fina han mostrado menor cantidad de raíces. Los resultados obtenidos ayudarán a mejorar la modelización hidrológica y de los flujos de nutrientes en sistemas de riego por aspesion intensivos a escala de parcela y de cuenca.

Abstract The main goal of this work is to quantify the depth distribution of crop root system under sprinkler irrigation in the Ebro Valley (Spain), in order to use this information in hydrological and crop simulation models. Soil cylinders have been sampled in the anthesis phase of the four main crops: barley, corn, alfalfa and peas. Crop roots have been extracted by washing. No roots were observed below 40 cm for all considered crops. Up to that depth the density of the root system clearly decreases with depth for maize and alfalfa. Almost 80% of the roots are found in the first 20 cm of the soil, although barley has shown a more homogeneous distribution in depth. Considering all soil profile, more roots density have been found in this work than in previous studies, especially for barley and corn, which is justified by the intensification of irrigated cultivation. However, legume crops on fine-textured soils have shown less roots density. The results obtained will help to improve the hydrological and nutrient load modeling in sprinkler intensive irrigation systems at both field and watershed scales.

Diversity of bioindicator arthropods in two cultural systems in the Ribatejo region: Monoculture/cultural succession

Resumo Os artrópodes representam uma grande percentagem do total de espécies da fauna do solo e, independentemente das funções que desempenham fornecem importantes serviços ao ecossistema que dependem de práticas culturais/fitossanitárias que condicionam espécies presentes e suas interações. Neste trabalho, avaliou-se abundância dos taxa de artrópodes considerados como bioindicadores de qualidade do solo, entre 2018 e 2021, no Ribatejo, em dois campos piloto com diferentes sistemas culturais: (i) rotação de batata e milho (Golegã) e (ii) sistema de monocultura de tomate para indústria (Vila Franca Xira). Nos dois campos instalaram-se 16 armadilhas “pitfall” com etilenoglicol, em cada momento de amostragem/local, tendo sido recolhidas após 7 dias. Os artrópodes capturados foram separados em morfotipos e identificados. O número total de morfotipos separados foi 62, 157, 132 e 117, em 2018, 2019, 2020 e 2021, respetivamente. O campo com monocultura manifestou, durante os 4 anos de amostragem, biodiversidade de artrópodes inferior ao campo com rotação. No que diz respeito aos carabídeos, no campo com rotação observaram-se 9 (2019) e 13 morfotipos (2020), respetivamente, e no campo com monocultura 3 morfotipos (2019) e nenhum carabídeo (2020). Os resultados indicam tendência para maior biodiversidade e populações mais equilibradas com a continuação da prática de rotação.

Abstract Arthropods represent a large percentage of the soil fauna and, regardless of the functions they perform, they all provide important ecosystem services, which depend on cultural/phytosanitary practices that influence the species present and their interactions. In the present study, the abundance of different taxa of arthropod bioindicators of soil quality were evaluated along 2018-2021 in the Ribatejo region in two sperimental fields with different crop systems: (i) potato and maize rotation (Golegã) and (ii) processing tomato monoculture system (Vila Franca Xira). Sixteen pitfall traps with ethylene glycol were installed for 7 days at each sampling time/site. The captured arthropods were separated into morphotypes and identified. The results revealed that the total number of separate morphotypes was 62, 157, 132 and 117, in 2018, 2019, 2020 and 2021, respectively. The field with monoculture revealed, during the 4 years of sampling, an arthropod biodiversity lower than the field with crop rotation. With regard to carabids, in the field with rotation, 9 (2019) and 13 morphotypes (2020) were observed, respectively; and in the field with monoculture only 3 morphotypes (2019) and no carabid (2020) were collected. A trend towards greater biodiversity and more balanced populations was observed with the rotation practice maintenance.

Compost application and sprinkler irrigation lowers the risk of As and Cd accumulation in rice grain

Resumo Foi instalado um ensaio de campo junto ao rio Gévora (“Las Vegas Bajas de Guadiana”, Extremadura, Espanha), durante 3 anos, para avaliar a influência da aplicação de composto de resíduos da produção de azeite (bagaço de azeitona ou 'Alperujo'), e de diferentes sistemas de rega, na acumulação de As e Cd no arroz. A rega deficitária (aspersão) levou a uma diminuição na acumulação de As no grão, quando comparada com a rega por inundação, atingindo concentrações de As no grão nos tratamentos aeróbios mais de 5 vezes inferior à atingida nas condições de rega por inundação. A concentração de As no grão, nos tratamentos aeróbios, atingiu valores inferiores ao limite estabelecido pela Comissão Europeia (0.20 mg kg-1 no grão de arroz, peso fresco), e mesmo inferiores ao limite estabelecido para arroz branco polido para utilização em alimentos para bebés (0.10 mg kg-1). Porém, um efeito contrário foi observado na acumulação de Cd no grão, que aumentou nos tratamentos aeróbios. A aplicação de composto (80 t ha-1 no primeiro ano), foi capaz de contrabalançar esse efeito negativo, levando a uma diminuição na acumulação de Cd no grão, em comparação com a produção obtida sem aplicação de composto (e.g., uma diminuição de 0,080 para <0,010 mg Cd kg-1 no grão, em sementeira direta com rega por aspersão), sem aumentar a concentração de As no grão. Por isso, foi possível concluir que, o cultivo aeróbio de arroz, com a aplicação simultânea de um corretivo orgânico maturado e estável, constitui uma boa solução para, simultaneamente, diminuir o risco de acumulação de As e Cd nos grãos de arroz.

Abstract A field experiment was set-up near the Gévora River (“Las Vegas Bajas de Guadiana”, Extremadura, Spain), for 3 years, to evaluate how the application of compost from olive mill waste, influences the accumulation of As and Cd in rice grain under different irrigation systems. The deficit irrigation (sprinkler irrigation) was able to lower the accumulation of As in the grain, when compared to the flooding irrigation systems, achieving As concentrations in the grain more than 5-times lower in the aerobic treatments than in the flooding irrigation conditions. The As concentrations in the aerobic treatments achieved values below the regulated limits established by the European Commision (0.20 mg kg-1 in the rice grain, fresh material), and even below the limit set for white polished rice intended to produce food for infants (0.10 mg kg-1). However, a contrary effect was observed on Cd accumulation in the grain, which increased in the aerobic treataments. Compost application (80 t ha-1 in the first year), was able to counterbalance that negative effect, lowering Cd accumulation in the rice grain, relatively to the non-treated counterparts (e.g., a reduction from 0.080 to <0.010 mg Cd kg-1 in the grain, in direct seeding with sprinkler irrigation), without increasing grain As concentrations. It was possible to conclude that, the aerobic cultivation of rice, with the simultaneous application of a mature and stable organic amendment, can be considered a good solution to, simultaneously, lower the risk of accumulation of As and Cd in the rice grain.

Soil adequation with organo-mineral substrates designed from wastes for Blueberry

Abstract Perú is the world greatest exporter of blueberry, crop that needs acid soil pH and high content of organic matter. The later is obtained from forest topsoil or peat (from north of Europe), unsustainable fact. This study shows a friendly environmental and sustainable alternative, organo-mineral substrates made by wastes (“Agrotec”). Four treatments [Control (C), Chicken manure (CM), Agrotec A (AA) and Agrote B (AB)] were used for basal dressing, where 6 months age blueberry plants were planted. It was followed a completely randomize block experimental design monitoring either edaphic and plant physiology parameters for ~9 months. Soil results showed how CM supply a high -but punctual- dose of nutrients and organic matter. Contrarily, designed substrates Agrotec A and B released nutrients gradually because were previously stabilized, which triggered a slow mineralization within soil. Thus, soil parameters under CM application showed an unstable behaviour respect to AA and AB. Physiological results showed a fruit yield increase with AA a AB (100 and 44%) compared to CM. Even though they are preliminary results in field conditions, It seems that designed substrates are efficient along the time and a sustainable alternative for blueberry soil adequation.

Resumen Perú es el mayor exportador mundial de arándano, el cual necesita suelos con pH ácido y altos contenidos de materia orgánica. Esta última se obtiene del horizonte superficial de los suelos forestales o de turberas (procedente del norte de Europa), lo cual es una práctica insostenible. Este estudio muestra alternativas sostenibles, los substratos órgano-minerales elaborados a base de residuos (“Agrotec”). Cuatro tratamientos [Control (C), Gallinaza (CM), Agrotec A (AA) y Agrotec B (AB)] fueron usados como abonado de fondo, donde plantas de arándano de 6 meses de edad fueron transplantadas. Se realizó un diseño experimental de bloques al azar monitoreando tanto los parámetros edáficos como fisiológicos durante ~9 meses. Los resultados del suelo mostraron como la gallinaza aportó una gran cantidad -pero puntual- de nutrientes y materia orgánica. Por el contrario, los substratos diseñados Agrotec A y B liberaron gradualmente los nutrientes debido a su precvio proceso de estabilización, lo cual permite una mineralización más lenta en el suelo. Los resultados fisiológicos mostraron un incremento en el rendimiento con AA y AB (100 y 44%) comparado a la gallinaza. Aunque son resultados preliminares en campo, los substratos diseñados son eficientes a lo largo del tiempo y son una alternativas sostenibles para la adecuación del suelo para el arándano.

Organic matter quality and phytotoxicity loss in progressive composting stages of olive pomace

Resumo Foram avaliados quatro tratamentos de compostagem aeróbica com diferentes matérias primas (BA: bagaço de azeitona, ES: estrume, CA: casca de amendôa) durante 176 d: pilha A com 44% BA, 25% ES, 25% CA e revolvimento; pilha B com 44% BA, 11% ES, 44% CA e revolvimento; pilha C com 25% BA, 50% ES, 25% CA e revolvimento; pilha D com 44% BA, 11% ES, 44% CA e sem revolvimento, de modo a testar os três fatores limitantes do BA: alta relação C/N, elevada humidade e teor de polifenóis. As variáveis analisadas nas pilhas, quinzenalmente, foram (n=160): densidade, humidade, fração grosseira, pH, condutividade elétrica (CE), matéria orgânica (MO), cinzas e cor; a análise elementar CHNO foi determinada por análise química elementar e a fitotoxicidade conforme o índice de Munoo-Liisa (MLV). Os resultados do diagrama de Van Krevelen (H/C vs O/C) mostram uma ligeira deshidrogenação nos primeiros 98 d, seguida por uma degradação seletiva de hidratos de carbono e um aumento da aromatização após 120 d. A análise de componentes principais (ACP) mostrou que a maior variabilidade é explicada pela qualidade da MO (83%), onde o teor de C (C/N alta) diminui conforme aumenta a disponibilidade de N e o pH. Por outro lado, verifico-se que a MLV é explicada (52%) pela alifaticidade dos constituintes orgânicos no composto (H/C alta).

Abstract Four treatments of aerobic composting with different raw materials (BA: olive pomace, ES: manure, CA: almond husk) were evaluated during 176 days: pile A with 44%BA, 25%ES, 25%CA and turning; pile B with 44%BA, 11%ES, 44%CA and turning; C pile with 25%BA, 50% ES, 25%CA and turning; D pile with 44%BA, 11%ES, 44%CA and without turning over, in order to test the three limiting factors of BA: high C/N ratio, humidity and content of polyphenols. The routine variables analyzed bi-weekly were (n=160): density, humidity, coarse fraction, pH, electric conductivity (EC), organic matter (OM), ash and color; CHNO was determined by chemical elemental analysis and the phytotoxicity according to the Munoo-Liisa index (MLV). Van Krevelen diagram´s results (H/C vs O/C) show a slight dehydrogenation in the first 98 d, followed by a selective degradation of carbohydrates and an increase in the aromatization of the compounds after 120d. The principal component analises (PCA) showed that the greatest variability is explained by the OM quality axis (83%), where the C content (high C/N) decreases as the N availability and pH increases, on the other hand, the MLV was explained (52 %) by the aliphaticity of the organic constituents in the compost (high H/C).

Characterisation of physical-chemical and fertility dynamics of mangrove soils from Guinea-Bissau in different agroecological conditions underlying paddy rice cultivation

Abstract Mangrove swamp rice production is of vital importance in most West African countries including Guinea Bissau. Even in a small country, different agroecological conditions underlying rice cultivation exist, and are mostly attributed to precipitation and temperature which impact soil acidity, salinity, and nutrient availability. The purpose of this study was to understand the physical, chemical, and nutritional properties of mangrove soils considering their variability and distribution in order to highlight the most adequate management practices. Based on field monitoring and three soil sampling dates, before and during the rice production cycle, in two different coastal regions of Guinea Bissau (Oio and Tombali), the most representative soil agroecological conditions were characterised. In the Tidal Mangrove (TM) swamps, the results showed that salinity and acidity concentrations were reduced to non-toxic levels at the nursery or transplantation moments. However, results from field observation showed that in those TM fields with limited drainage, the saltwater intrusion may create an imminent threat, with higher salt concentration corresponding to an electrical conductivity of approximately 6 mS cm−1 risking total production losses. In the Associated Mangrove (AM) swamps, acid and salinity levels do not pose a problem, but very low macronutrient levels (up to 2 times lower than TM), limite productivity in these soil. Furthermore, results showed high variability in physical chemical properties in the soils from the main agroecological conditions indentified and a positive down-stream gradient in soil fertility.

Resumo A produção de arroz de mangal é de vital importância na maioria dos países da África Ocidental, incluindo a Guiné-Bissau. Mesmo em áreas de reduzida dimensão, existem diferentes condições agroecológicas subjacentes ao cultivo de arroz, e são principalmente atribuídas à precipitação e temperatura que afetam a acidez do solo, salinidade e disponibilidade de nutrientes. O objetivo principal deste estudo foi conhecer as dinâmicas nas propriedades físicas, químicas e nutricionais dos solos de mangal, considerando a sua variabilidade e distribuição, a fim de evidenciar melhores práticas de gestão. Com base na monitorização de campo e em três campanhas de amostragem de solo antes e durante o ciclo de produção do arroz, em duas regiões costeiras distintas da Guiné-Bissau (Oio e Tombali), foi feita a caracterização das principais condições agroecológicas dos solos. Nos mangais influenciados pelas marés, Mangais de Maré (TM) os resultados mostraram que as condições de salinidade e acidez foram reduzidas a níveis não tóxicos nos momentos de início do viveiro ou do transplante. No entanto, as observações dos resultados mostraram que em campos de TM que possuem drenagen limitada, a intrusão de água salgada pode criar um risco iminente com concentração salina levando a condutividade eléctrica a valores de aproximadamente 6 mS cm−1 causando até perdas importantes de produção. Nos Mangais Associados (AM), os níveis de acidez e salinidade não põem um problema, mas níveis muito baixos de principais macronutrientes (até 2 vezes menores que TM), limitam a produção. Além disso, os resultados mostraram alta variabilidade nas propriedades físico-químicas dos solos das principais condições agroecológicas identificadas e um gradiente positivo a jusante na fertilidade do solo.

Comparison between mineral and organic fertilization on forage corn culture: impact on yield, total carbon and nutrients NPK of soil

Resumo Compara-se a fertilização mineral versus substrato orgânico (SO), no rendimento do milho forrageiro e nos teores em carbono total (Ct) e NPK do solo. A morfologia do perfil cultural resultante da mobilização do solo com charrua x fresagem, na distribuição dos resíduos orgânicos (RO) e do substrato orgânico (SO), carateriza-se por o horizonte Ap2 apresentar unidades morfológicas de elevada acumulação de RO à mistura com terra (TERO), no tratamento A (TA), e acumulação de SO mais terra (TESO) no tratamento B (TB). A relação entre unidades constituídas por terra (TE) e TERO é de 70:30 no TA e de 50:50 entre TE e TESO no TB. O conforto nutricional da cultura foi muito elevado e constante no TA, mas superior e crescente no TB. O rendimento em matéria verde foi fraco no 1º ano, devido ao acentuado défice hídrico, e alto no 2º ano. As diferenças entre TB e TA foram de 4,7t/ha e de 9.8t/ha. No período de 462 dias, registou-se no TA um decréscimo em Ct de -1,6g/kg e no TB um acréscimo de +4,7g/kg, demonstrativas da elevada resiliência do SO-MUSAMI, o qual potencia a produção.

Abstract Mineral fertilization versus organic substrate (SO) is compared on forage corn yield, total carbon (Ct) and NPK contents. The morphology of the cultural profile resulting from tillage with moldboard x rotovator, in the distribution of organic residues (RO) and organic substrate (SO), is characterized by soil horizon Ap2 presenting morphological units of high accumulation of RO mixed with soil (TERO) in treatment A (TA), and accumulation of SO plus soil (TESO) in treatment B (TB). The relation between soil units (TE) and TERO units is 70:30 in the TA and 50:50 between TE and TESO in the TB. The nutritional comfort of the forage culture, confirmed by the analyses of the soil samples, was very high and constant in TA, but higher and increasing in TB. Green biomass yield of forage corn was weak in the 1st year, explained by the severe water deficit, and high in the 2nd year. The differences between TB and TA in yield were 4.7t/ha and 9.8t/ha. In the period of 462 days, there was a decrease in Ct of -1.6g/kg in TA and an increase of +4.7g/kg in TB, demonstrating the high resilience of SO-MUSAMI, which enhances production and soil sustainability.

Composting waste from the kiwi crop

Resumo A reutilização dos resíduos provenientes da atividade agrícola através da compostagem apresenta vantagens ambientais e agronómicas. A estilha da poda da cultura de kiwi possui uma elevada razão C/N e poderá ser um bom material estruturante para adicionar com outro material mais facilmente biodegradável de modo a obter uma compostagem efetiva. Com este objetivo, avaliou-se o processo de compostagem de estilha da poda com refugo de frutos de kiwi, misturados nas proporções de 2:1, 1:1 e 1:2 (estilha:kiwi, p:p). A temperatura mais elevada registou-se na pilha com mais frutos de kiwi (57 °C), que possuía uma menor razão C/N. A redução da razão C/N de valores iniciais entre 49 e 59 para valores finais entre 18 e 21, e o aumento do teor de N total de valores entre 9 e 11 g kg-1 para valores entre 22 e 27 g kg-1 durante a compostagem, poderá contribuir para aumentar a disponibilidade de nutrientes para as culturas. O grau de maturação e a ausência de fitotoxicidade avaliada pelo índice de germinação, a diminuição da razão C/N, e as caraterísticas químicas avaliadas, são indicativos da qualidade dos compostados destes resíduos provenientes da cultura de kiwi.

Abstract The reuse of waste from the agricultural activity through composting has environmental and agronomic advantages. Kiwi pruning chips have a high C/N ratio and may be a good structuring feedstock material to add with another more easily biodegradable material in order to achieve effective composting. With this objective, the process of composting pruning chips with kiwi fruit waste, mixed in proportions of 2:1, 1:1 and 1:2 (chips:kiwi, w:w) was evaluated. The highest temperature was recorded in the pile with the highest content of kiwi fruits (57 °C), which had a lower C/N ratio. Reducing the C/N ratio from initial values between 49 and 59 to final values between 18 and 21, and increasing the total N content from values between 9 and 11 g kg-1 to values between 22 and 27 g kg-1 during composting, may contribute to increase the availability of nutrients for crops. The degree of maturation and the absence of phytotoxicity evaluated by the germination index, the decrease in the C/N ratio, and the chemical characteristics, are indicative of the quality of the composts from these kiwi crop residues.

Soil Characteristics Under the Influence of Cashew Trees in East-Timor

Abstract Cashew (Anacardium occidentale L.) is among the most important cash crops in tropical countries. In East-Timor, nowadays, cashew has been implemented as an alternative cash crop to coffee. The aim of this work was to analyse the soils cultivated with cashew and verify whether there has been any change in their characteristics as a result of this plantation. In four selected sites, soil samples were collected under the cashew canopy (UC) and outside the canopy influence (OP) to assess soil dynamics and evaluate physical and nutrient variability. Significant differences were found on the amount of organic C and extractable K at the surface horizon, with much higher amounts of those elements in the area of influence of the trees. The same pattern was found for extractable P, total N, Cation Exchange Capacity (CEC) and exchangeable Ca2+, Mg2+ and K+, however without statistical significances. Those differences are only evident at the surface horizon (0-10 cm) and the understorey vegetation seems not to be influenced by trees.

Resumo O cajueiro (Anacardium occidentale L.) está entre as mais importantes culturas comerciais dos países tropicais. Actualmente, em Timor-Leste, a cultura do caju tem sido muito implementada como alternativa ao café. O objectivo deste trabalho foi analisar os solos cultivados com caju e verificar se houve alguma alteração nas suas características em resultado desta plantação. Em quatro locais seleccionados foram recolhidas amostras de solo sob a copa dos cajueiros (UC) e fora da influência da copa (OP) para avaliar a dinâmica do solo e avaliar a variabilidade das suas características. Foram encontradas diferenças significativas na quantidade de C orgânico e K extraível no horizonte superficial, com quantidades muito mais elevadas desses elementos na área de influência das árvores. O mesmo padrão foi encontrado para o P extraível, o N total, a capacidade de troca catiónica (CTC) e o Ca2+, o Mg2+ e o K+ permutáveis, contudo sem que as diferenças encontradas tivessem significado estatístico. Estas diferenças são apenas evidentes no horizonte superficial (0-10 cm) e a vegetação sob coberto parece não ser influenciada pelas árvores.

The effects of organic-mineral fertilizer application of barley crop in SW Buenos Aires (Argentina)

Resumen La intensificación ganadera en la zona Pampeana genera grandes cantidades de residuos orgánicos que deben gestionarse adecuadamente para evitar impactos negativos en el ambiente. El compostaje se considera una forma de reciclar los estiércoles animales para valorar su capacidad como fertilizantes. La densificación del material pelletizado puede ser una alternativa para la aplicación de compost mejorando el transporte, el almacenamiento y la dosificación. El objetivo de este trabajo, consistió en evaluar el uso de fertilizantes órgano-minerales en base a compost, pelletizados como fuente de N y P en el cultivo de cebada (Hordeum vulgare L.) y comparar su comportamiento respecto a fuentes de N y P inorgánicas. Se realizó un ensayo experimental a campo que incluyó 4 tratamientos y un testigo sin fertilización. Los fertilizantes P se aplicaron incorporados a la siembra y los fertilizantes N al macollaje en superficie. Se realizó el seguimiento de variables biofísicas no destructivas en estado vegetativo (Chl, LAI y fCOVER) y el rendimiento en grano (kg ha-1) a cosecha. No se encontraron diferencias significtiva de los tratamientos aplicados, lo que suguiere que podrían reemplazarse de forma parcial los fertilizantes minereales e incorporarse materia orgánico al suelo reciclando y valorizándose residuos ganaderos.

Abstract Livestock intensification in the Pampas area generates large quantities of organic wastes that must be properly managed to avoid negative impacts on the environment. Composting is considered to recycle animal manures to value their capacity as fertilizers. The densification of pelletized material can be an alternative for compost application, improving transportation, storage and dosage. The objective of this work was to evaluate the use of organo-mineral fertilizers based on pelletized compost as a source of N and P in barley (Hordeum vulgare L.) and compare their performance with inorganic sources of N and P. An experimental field trial was carried to evaluate the use of pelletized compost-based organo-mineral fertilizers as a source of N and P in barley (Hordeum vulgare L.). An experimental field trial was carried out including 4 treatments and a control without fertilization. P fertilizers were applied incorporated at sowing and N fertilizers at surface-applied. Non-destructive biophysical variables were monitored at the vegetative stage (Chl, LAI and fCOVER) and grain yield (kg ha-1) at harvest. No significant differences were found in the treatments applied, suggesting that mineral fertilizers could be partially replaced and organic matter could be incorporated into the soil by recycling and valorizing livestock residues.

Development of a liquid N fertilizer from an agro-industrial effluent

Abstract Anaerobic digestion (AD) has been largely studied and it is widely applied for manure treatment in Europe, although its implementation is scarce in Spain and Portugal. The major benefit of AD is the production of renewable energy in the form of methane and digestate that is used as fertilizer, as it contains N, P and K. The aim of this work was to use gas-permeable membrane technology to capture N from slurry co-digested with orange peel residue, obtaining a liquid solution of ammonium sulfate that has been tested as a fertilizer in micropot trials. The data obtained show a recovery of 62% of the N from the digestate, and a recovery rate of N of 43.0 ± 6.6 g N per m2 of membrane and per day. The results of the micropot test showed that the liquid ammonium sulfate solution had a fertilizing effect similar to that of the mineral N fertilization.

Resumen La codigestión anaerobia del purín y otros residuos agroindustriales es uno de los tratamientos de residuos más utilizados en Europa, aunque su implantación en España y Portugal es muy escasa. El mayor beneficio de este tratamiento es la producción de metano y digestado, que se utiliza como fertilizante debido a su contenido en nitrógeno, fósforo y potasio. El objetivo de este trabajo ha sido utilizar la tecnología de membranas permeables a los gases para capturar el N del digestado de purín codigerido con residuos de piel de naranja, obteniendo una solución líquida de sulfato de amonio que se ha testado como fertilizante en ensayos en micromacetas. Los datos obtenidos muestran una recuperación del 62% del N del digestado, y una tasa de recuperación de N de 43.0 ± 6.6 g N por m2 de membrana y por día. Los resultados del ensayo en micromacetas muestran que solución líquida de sulfato de amonio tuvo un efecto fertilizante similar al de la fertilización con nitrógeno mineral.

Application of a microbial consortium immobilized onto a biochar for the remediation of a polluted soil with hydrocarbons

Abstract The contamination of soils by hydrocarbons is a serious environmental problem both due to the persistence of this pollution and by its effects on even the most pristine areas of the planet. Hydrocarbon decontamination techniques entail a high cost, imply in many cases their off-site treatment, and entail environmental risks. In contrast, the use of microbiological techniques through the addition of microbial consortia with the capacity to degrade these contaminants, are alternatives for soil biorecovery that are gathering growing interest in the construction of biopiles or ecopiles. However, for an effective application of these biotechnological techniques, it is necessary to guarantee an effectiveness in the action of these microbial consortia, whose persistence in soil is generally low. In this work, the stabilization of a microbial consortium specialized in the degradation of hydrocarbons and isolated from the own soil, has been studied through its immobilization on two classes biochars obtained form apricot stones at pyrolysis temperatures of 450° and 650°C, respectively, as well as the increase of its efficiency rate through the addition of rhamnolipids. The introduced microbial consortium achieved a degradation of 17% of the highest molecular weight hydrocarbons, an efficiency that was increased with the application of biochar and rhamnolipids up to 25% of their initial content.

Resumen La contaminación de suelos por hidrocarburos es un grave problema ambiental tanto por su persistencia como por su afección hasta las zonas más prístinas del planeta. Las técnicas de descontaminación de hidrocarburos suponen un elevado coste, implican en muchos de los casos su tratamiento exsitu y conllevan también riesgos ambientales. En contraposición, el empleo de técnicas microbiológicas mediante la adición de consorcios microbianos con capacidad para degradar estos contaminantes, son alternativas de biorrecuperación de suelos, que mediante la construcción de biopilas o ecopilas están reuniendo un creciente interés. Sin embargo, para una eficaz aplicación de estas técnicas biotecnológicas, es necesario garantizar una efectividad en la acción de estos consorcios microbianos, cuya persistencia en el suelo es generalmente baja. En este trabajo se ha buscado la estabilización de un consorcio microbiano especializado en la degradación de hidrocarburos y aislado del propio suelo contaminado, mediante su inmovilización sobre dos tipos de biochars obtenidos a partir de huesos de albaricoque con temperaturas de pirólisis de 450° y 650°C, respectivamente, así como el incremento de su eficacia mediante la adición de ramnolípidos. El consorcio microbiano introducido consiguió una tasa de degradación del 17% de los hidrocarburos de mayor peso molecular, eficiencia que se incrementó con la aplicación de biochar o ramnolípidos hasta el 25% de su contenido inicial.

Importance of cover crops in increasing the degree of mycorrhization of tomato and maize

Resumo Os microrganismos benéficos ocorrem naturalmente em ecossistemas pouco intervencionados, mas muitas práticas associadas à agricultura intensiva resultam em desequilíbrios de biodiversidade que os desfavorecem relativamente a outras espécies não-benéficas. Nestes sistemas intensivos, a ocupação do solo no período de outono-inverno com culturas de cobertura à base de leguminosas, gramíneas, ou misturas biodiversas de ambas, vai favorecer o enriquecimento do solo em microrganismos benéficos, que ficarão disponíveis para interagir com a cultura principal, com todos os benefícios que daí advêm. A adoção de práticas que favoreçam a micorrização podem ter um papel muito importante. É conhecido que determinadas espécies, como é o caso do azevém anual, micorrizam muito facilmente e o seu cultivo enriquece o solo em fungos endomicorrízicos autóctones, que poderão depois associar-se às culturas seguintes. Assim, neste estudo, foram utilizados métodos de microscopia ótica para a visualização de estruturas das endomicorrizas no interior do tecido redicular e determinou-se a percentagem de micorrização. Os resultados mostram um aumento da percentagem de micorrização, quer no milho, quer no tomateiro, induzidas pela introdução de culturas de cobertura do tipo mistura biodiversa e azevém.

Abstract Beneficial microorganisms occur naturally in little-intervened ecosystems, but many practices associated with intensive agriculture result in biodiversity imbalances that disadvantage them relatively to other non-beneficial species. In these intensive systems, the occupation of the soil in the autumn-winter period with cover crops based on legumes, grasses, or biodiverse mixtures of both, will favor the enrichment of the soil in beneficial microorganisms, which will be available to interact with the main crop. The adoption of practices that favor mycorrhization can also play a very important role. It is known that certain species, such as annual ryegrass, mycorrhize very easily and their cultivation enriches the soil with autochthonous endomycorrhizal fungi, which can then be associated with subsequent crops. Thus, it was used microscopic methods in order to visualized endomicorrhizae structures and then, calculate the percentage of micorrization in the inner of radical tissue. with annual tye grass and biodiverse mixtures, we found the increase of mycorrhization percentage both maize and tomatoe cultures.

Effect of different forms of organic matter on tomato seedlings in the greenhouse

Resumen El objetivo de este trabajo fue comparar los efectos de dos fuentes de materia orgánica (compost de desmotadora de algodón y gallinaza) con un sustrato comercial a base de turba sobre la germinación, crecimiento y contenido en N, P y K plántulas de tomate (Lycopersicum esculentum cv. Momotaro) bajo condiciones de invernadero. Los resultados mostraron que con el sustrato a base de gallinaza se obtuvieron los valores más altos de altura de plántula de tomate, diámetro de tallo, número de hojas por plántula así como contenidos de N, P y K, seguido del sustrato a base de compost de algodón y de turba. Estos resultados sugirieron que la composición química de la materia orgánica influyó de forma diferente en la emergencia de la semilla, el crecimiento y contenidos de N, P y K en las plántulas de tomate. Estos parámetros fueron mayores cuando se aplicó una fuente de materia orgánica facilmente degradable con un mayor contenido en ácido fúlvico y mayor contenido de proteínas de bajo peso molecular. Por otro lado, estos resultados respaldan estudios previos que muestran que los compost se pueden usar con muy buenos resultados como medios de crecimiento alternativos a los sustratos a base de turba.

Abstract The objective of this work was to compare the effects of two sources of organic matter (cotton gin compost and poultry manure) with a commercial peat-based substrate on germination, growth and N, P and K content of tomato (Lycopersicum esculentum cv. Momotaro) under greenhouse conditions. The results showed that the poultry manure-based substrate had the highest values of tomato seedling height, stem diameter, number of leaves per seedling as well as N, P and K contents, followed by the cotton gin compost and peat. These results suggested that the chemical composition of organic matter influenced differently seed emergence, growth and N, P and K contents in tomato plants. These parameters were higher when a source of organic matter easily degradable with a higher content of fulvic acid and a higher content of low molecular weight proteins, was applied. On the other hand, these results support previous studies showing that composts can be used with very good results as alternative growth media to peat-based substrates.

Assessment of new pelletized biofertilizers in wheat: a pot experiment

Resumen La expansión de la agricultura y el aumento de la demanda de carne han incrementado las actividades ganaderas intensivas. Los residuos generados son problema ambiental, pero también son una fuente de nutrientes. La pelletización podría ser una alternativa para el uso masivo de estos materiales. El objetivo de este trabajo fue evaluar la aplicación de biofertilizantes pelletizados y en mezcla con fertilizantes químicos, en cultivos extensivos. Se prepararon macetas con suelo de textura franca y bajo nivel de fertilidad, para sembrar trigo (Triticum aestivum L.) en invernadero. El diseño experimental (n=102) incluyó 16 tratamientos y un testigo sin fertilización. Los fertilizantes se aplicaron en dos momentos diferentes: pre-siembra y siembra. Se cosechó la producción vegetativa, se contabilizaron el numero de macollos por planta y se secó el material en estufa para determinar materia seca. No se encontraron diferencias signifcativas entre fechas de aplicación de fertilizantes. Se encontraron diferencias significativas (p<0.0001) entre los tratamientos para ambas variables estudiadas. Los rendimientos fueron similares entre los tratamientos minerales y los orgánicos-minerales, esto sugiere que podrían economizarse fertilizantes químicos y reciclar grandes cantidades de N y P presentes en los residuos orgánicos, además de incoporar materia orgánica al suelo.

Abstract The expansion of agriculture and increased demand for meat have increased intensive livestock farming activities. The waste generated is an environmental problem, but it is also a source of nutrients. Pelletization could be an alternative for the massive use of these materials. The objective of this work was to evaluate the application of pelletized biofertilizers and in mixture with chemical fertilizers in extensive crops. Pots were prepared with loam-textured soil and low fertility level, to plant wheat (Triticum aestivum L.) in greenhouses. The experimental design (n=102) included 16 treatments and a control without fertilization. Fertilizers were applied at two different times: pre-sowing and sowing. Vegetative production was harvested, the number of tillers per plant was counted and the material was dried in an oven to determine dry matter. No significant differences were found between fertilizer application dates. Significant differences (p<0.0001) were found between treatments for both variables studied. Yields were similar between mineral and organic-mineral treatments, suggesting that chemical fertilizers could be economized and large amounts of N and P present in the organic residues could be recycled, in addition to incorporating organic matter to the soil.

Obtaining an agronomic/environmental biostimulant by enzymatic hydrolysis of okara

Resumen En el presente trabajo se ha desarrollado un proceso enzimático destinado a la valorización de la okara, mediante su conversión en un producto bioestimulante agronómico/ambiental altamente biodisponible y con alto contenido en C, N, P, K.. La okara es un subproducto insoluble resultante en el proceso de obtención de la leche de soja y tofu. Aunque tiene un alto valor nutricional (proteínas, fibra y lípidos) destaca su composición en compuestos bioactivos, como isoflavonas, vitaminas y oligoelementos, presenta problemas de utilización, por su alto contenido en agua que lo convierte en un producto muy perecedero y fácilmente fermentable. Todo ello lo convierte en un sustrato idóneo para la obtención de compuestos agronómico/ambientales. El proceso se basa en el uso de diferentes enzimas hidrolíticas, que conducen a la solubilización e hidrólisis de las moléculas orgánicas (proteínas y azúcares) e inorgánicas (P y K) El proceso enzimático diseñado consiste en una hidrólisis multienzimática secuencial donde actuan proteasas, fitasas y carbohidrolasas. El extracto enzimático ha sido caracterizado químicamente, destacando su alto contenido en péptidos y aminoácidos libres (contenido orgánico soluble compuesto en un 64% por moléculas de <1 KDa, solubilización de un 61% del total de proteínas), así como en fosfato de origen orgánico (solubilización de un 79,1% del total de P), K (solubilización de un 86,6% del total de K) y glucosa libre.

Abstract In the present work, an enzymatic process has been developed for the valorization of okara, through its conversion into an agronomic/environmental biostimulant product with high bioavailability and high content in C, N, P and K. Okara is an insoluble by-product resulting from the process of obtaining soy milk and tofu. Although it has a high nutritional value (proteins, fiber and lipids), where its composition of bioactive compounds such as isoflavones, vitamins and trace elements stands out, it presents problems of utilization due to its high water content, which makes it a very perishable and easily fermented product. All this makes it an ideal substrate for obtaining agronomic/environmental compounds. The process is based on the use of different hydrolytic enzymes, which lead to the solubilization and hydrolysis of organic (proteins and sugars) and inorganic (P and K) molecules. The enzymatic process designed consists of a sequential multi-enzymatic hydrolysis involving proteases, phytases and carbohydrolases. The enzymatic extract has been chemically characterized, highlighting its high content in peptides and free amino acids (soluble organic content composed of 64% of molecules <1 KDa, solubilization of 61% of total proteins), as well as in organic phosphate (solubilization of 79.1% of total P), K (solubilization of 86.6% of total K) and free glucose.

BioComp_2.0 - Production of biological organic composts for the control of water hyacinth and valorization of by-products resulting from agricultural, forestry and agro-industrial activities

Resumo O mercado da Agricultura Biológica encontra-se em franco crescimento em todo o Mundo e particularmente na União Europeia que definiu a ambiciosa meta de 25% da área agrícola em modo de produção biológico até 2030. A Agricultura Biológica apresenta-se como sendo um modo de produção sustentável, consistindo num sistema global de gestão das explorações agrícolas e de produção de géneros alimentícios que combina as melhores práticas ambientais, um elevado nível de biodiversidade, a preservação dos recursos naturais, a aplicação de normas exigentes em matéria de bem-estar dos animais e método de produção em sintonia com a preferência de certos consumidores por produtos resultantes de processos naturais, isentos de moléculas sintéticas e amigos do ambiente. Prevendo-se igualmente o aumento da necessidade por matérias fertilizantes compatíveis com o modo de produção biológico, o projeto BioComp_2.0 (projeto de I&DT em copromoção) surge como uma proposta de desenvolvimento de compostos orgânicos biológicos produzidos a partir da planta invasora jacinto de água e de subprodutos agropecuários, florestais e agroindustriais, ainda pouco valorizados. O grande objetivo final é conseguir-se, deste modo, um controlo mais eficaz e economicamente viável do jacinto de água, espécie comum em Portugal e Espanha, ao mesmo tempo que se reforça e diversifica a oferta de fertilizantes (corretivos, substratos e adubos) para responder às crescentes necessidades do setor da Agricultura Biológica, numa ótica de pleno respeito pela Economia Circular. O projeto contempla diversas atividades de I&D complementadas com a validação do ciclo de vida e estudo da viabilidade económica da solução desenvolvida.

Abstract The organic farming market is rapidly growing all over the world and particularly in the European Union, which has defined the ambitious target of 25% of the agricultural area in organic production by 2030.The organic production system presents itself as a sustainable production method, consisting of a global system for the management of agricultural holdings and food production that combines the best environmental practices, a high level of biodiversity, the preservation of natural resources, the application of strict animal welfare standards and production method in line with the preference of certain consumers for products resulting from natural processes, free from synthetic molecules and environmentally friendly. Also foreseeing an increase in the need for fertilizing materials compatible with the organic production method, the BioComp_2.0 project (R&DT project in co-promotion) emerges as a proposal for the development of biological organic composts produced from the invasive water hyacinth plant and agricultural, forestry and agro-industrial by-products, which are still undervalued. The ultimate goal is to achieve, in this way, a more effective and economically viable control of water hyacinth, a common species in Portugal and Spain, while strengthening and diversifying the supply of fertilizers (amendments, substrates and fertilizers) to respond to the growing needs of the organic farming sector, with full respect for the Circular Economy. The project includes several R&D activities complemented with the validation of the life cycle and study of the economic viability of the developed solution.

Soil organic matter evaluation using two different methods in peach orchards from the Beira Inteior - Portuguese centre region

Resumo A quantificação do teor de matéria orgânica (MO) do solo é de elevada importância para a avaliação da sua fertilidade e da sua capacidade em armazenar carbono. De entre os métodos disponíveis, o de Walkley-Black (WB) e as perdas por incineração (PPI) são dois dos mais comuns. O método de WB tem sido utilizado para quantificar a MO mais facilmente oxidável. Este trabalho teve como principal objetivo avaliar a adequabilidade destes dois métodos na quantificação da MO em solos de pomares de pessegueiro da zona interior centro de Portugal. Para isso foram utilizadas um total de 49 amostras colhidas à profundidade de 0-30 cm. No caso do método PPI, as amostras foram incineradas a 450ºC durante 16 h e posteriormente a 800ºC durante 4 h. Observaram-se perdas de massa reduzidas após a incineração a 800ºC durante 4 h das amostras resultantes do método PPI. Apesar do método PPI apresentar valores superiores ao WB verificou-se uma boa correlação entre ambos (R2 = 0,636, P <0,001). A diferença obervada entre os dois métodos permitirá quantificar o teor de MO mais estável nestes pomares.

Abstract Soil organic matter (OM) quantification is of great importance to evaluate soil fertility and its capacity for carbon storage. Walkley-Black (WB) and loss on ignition (LOI) are two of the most common methods for OM quantification. WB method has been used to quantify the readily oxidizable OM. The main objective of this study was to evaluate the adequacy of these two methods for OM quantification in soils from the Portuguese inland centre region. A total of 49 soil samples (0-30 cm) were used. In LOI method, the samples were incinerated at 450ºC for 16 h and then at 800ºC for 4 h. Low weight losses were found when the samples obtained from the LOI method were incinerated at 800ºC for 4 h. Despite the higher values obtained from the LOI method, a good correlation was found between that method and the WB method (R 2 =0,636, P<0,001). The difference between the values obtained from the two methods indicates the more stable fraction of OM in soil which contributes to the long-term C storage.

Carbon loss in plants residues: effect of initial (bio)chemical characteristics

Resumo A gestão da matéria orgânica do solo, através da aplicação dos resíduos das culturas, pressupõe o conhecimento do respetivo processo de decomposição e mineralização, de modo a fornecer informações importantes, quer ao nível da libertação de nutrientes para as culturas, quer no rendimento de húmus, para a manutenção do fertilidade e qualidade do solo. O objetivo do presente trabalho é avaliar os processos de decomposição de diferentes resíduos vegetais, através da respetiva estimativa da dimensão e dinâmica, com base no ajustamento do modelo exponencial negativo de um reservatório. Os resultados revelaram diferenças significativas para os parâmetros C0 e kC, com os valores a variarem entre os 270 a 661 g/kg e 0,008 a 0,027 dia-1, respetivamente, de acordo com a ordem decrescente: Trem; Pt; Rm; e Fvid=Fcast=Fmac. Foram observadas correlações significativas entre a qualidade (bio)química inicial dos materiais e os C0 e kC, com os indicadores de Csol (r2 0,977***) e Len (r2 0,969 ***) dos resíduos vegetais a revelarem-se como os mais robustos nas estimativas da dimensão e dinâmica dos respetivos processos de perda de C. Estes resultados revelam a necessidade de integração de indicadores mais eficientes na avaliação dos processos de decomposição/humificação, de modo a tornar a aplicação de resíduos orgânicos mais ecocompatível.

Abstract The management of soil organic matter, through the application of crop residues, implies the knowledge of the respective decomposition and mineralization process, in order to provide important information, in terms of the release of nutrients to the crops and in the humus yield, for the maintenance soil fertility and quality. The objective of the present work is to evaluate the processes of decomposition of different plant residues, through the respective estimation of the dimension and dynamics, based on the adjustment of the negative exponential model of one pool. The results revealed significant differences for the parameters C0 and kC, with the values varying between 270 to 661 g/kg and 0.008 to 0.027 day-1, respectively, following the decreasing order: Trem, Pt, Rm and Fvid= Fcast=Fmac. Significant correlations were observed between the initial (bio)chemical quality of the materials and the C0 and kC, with the indicators of Csol (r2 0.977***) and Len (r2 0.969 ***) of the vegetal residues revealing the more robust results in estimation of the dimension and dynamics of C loss processes. These results reveal the need to integrate more efficient indicators in the evaluation of decomposition/humification processes, in order to make the application of organic residues more eco-frendly.

Analytical laboratories for soil fertility assessment, in Portugal

Abstract The main objective of this work was to obtain updated data from soil fertility laboratories located in Portugal. A survey was sent to the Heads of 32 laboratories and a reply was received from 25 of them. 14 of these labs belong to the Ministry of Education, 7 are private and 4 to the Ministry of Agriculture. In addition to soil they also analyse plant material and, the majority, organic soil improver and irrigation water. In the minimum package of analyses they offer (Summary Analysis) pH, organic matter, extractable phosphorus and potassium are always included and 72 % of them also include field texture. But this package differs greatly between labs with regard to the inclusion of other parameters. 76 % of the labs issue fertilisation recommendations, but only 20 % do so automatically. There is a relative homogeneity of methods for the parameters of the summary analysis, except for organic matter. Only two laboratories have accredited tests. The existence of a national interlaboratory test is felt to be important for internal quality control and harmonisation of methodologies.

Resumo O objetivo principal deste trabalho foi obter dados atualizados dos laboratórios que, em Portugal, analisam solo para avaliar a fertilidade do solo e apoiar a atividade agrícola no tocante à nutrição e fertilização das culturas. Enviou-se um inquérito aos responsáveis técnicos de 32 laboratórios, tendo recebido resposta de 25 deles. 14 destes lab. pertencem ao Ministério da Educação, 7 são privados e 4 do Ministério da Agricultura. Para além de solo analisam também material vegetal e, a maioria, corretivos orgânicos e águas de rega. No pacote mínimo de análises que oferecem (Análise sumária) todos analisam o pH, matéria orgânica, fósforo e potássio extraíveis e, em 72 % deles, também a textura de campo. Mas este pacote difere muito entre laboratórios no tocante à inclusão de outros parâmetros. 76 % dos laboratórios emitem recomendações de fertilização, mas apenas 20 % o fazem automaticamente. Existe relativa homogeneidade de métodos para os parâmetros da análise sumária, exceto no tocante à matéria orgânica. Apenas dois laboratórios têm ensaios acreditados. A existência de um teste Interlaboratorial nacional é sentida como importante para o controlo interno de qualidade e harmonização de metodologias.

Soil fertility and mineral nutrition of “Aljezur Sweetpotato”

Resumo Para avaliar a fertilidade do solo, o estado nutricional das plantas e determinar a composição mineral das raízes de reserva, selecionaram-se 29 parcelas de “Batata-doce de Aljezur”, tendo-se procedido à colheita e análise de amostras de solo, folhas e raízes de reserva. Os resultados revelaram que os solos são de textura arenosa, com teores baixos de matéria orgânica, pouco ácidos, teores altos de fósforo extraível e teores muito baixos de boro extraível e de Ca++; Mg++ e K+ de troca. As médias dos teores foliares de nutrientes na matéria seca foram as seguintes: 37,8 g kg-1 de N, 2,6 g kg-1 de P, 24,1 g kg-1 de K, 9,4 g kg-1 de Ca, 6,4 g kg-1 de Mg, 125 mg kg-1 de Fe, 255 mg kg-1 de Mn, 21 mg kg-1 de Zn, 11 mg kg-1 de Cu e 47 mg kg-1 de B. Nas raízes de reserva (>50 g), os teores médios de K (3,65 g kg-1) e de Mn (4,49 mg kg-1), expressos em peso fresco, foram o macro e o micronutriente mais exportados.

Abstract To assess soil fertility, plant nutritional status and to determine the mineral composition of storage roots, 29 plots of "Batata-doce de Aljezur" were selected and soil, leaf and storage root samples were taken and analysed. The results showed that the soils are sandy, with low levels of organic matter, moderately acidic, with high levels of extractable phosphorus and very low levels of extractable boron and exchange Ca++; Mg++ and K+. The mean leaf nutrient contents in the dry matter were as follows: 37.8 g kg-1 N, 2.6 g kg-1 P, 24.1 g kg-1 K, 9.4 g kg-1 Ca, 6.4 g kg-1 Mg, 125 mg kg-1 Fe, 255 mg kg-1 Mn, 21 mg kg-1 Zn, 11 mg kg-1 Cu and 47 mg kg-1 B. In the storage roots (>50 g), K and Mg were the most exported macro and micronutrient, with average contents of 3.65 g kg-1 K and 4.49 mg kg-1 Mg (wet weight).

Biochemical and microbiological soil effects of a biostimulant based on Bacillus licheniformis-fermented sludge

Abstract A fermentative process has been applied to carry out the conversion of sludge from slaughterhouse wastewater treatment into a biostimulant complex. The three biostimulant components are: a) The Bacillus licheniformis biomass, which is a plant growth promoter rhizobacteria (PGPR), and the organism in charge of the fermentative process, b) the enzymatic secretion of said microorganism, mainly peptidases and amidases (50%), involved in N metabolism, and glucanases (33.3%), involved in carbohydrate metabolism, and c) the hydrolyzed sludge organic matter, largely composed of peptides and free aminoacids. The biostimulant has been evaluated in soil at the biochemical and microbiological level. It induced a strong microbial stimulation of the soil, and produced the specific stimulation of PGPR soil bacteria, which was studied through a metabarcoding. Moreover, mainly when applying the soluble fraction of the biostimulant complex, it was found that the Bacillus licheniformis inoculum remains active in the environment at the end of the experiment.

Resumen Se ha aplicado un proceso fermentativo para llevar a cabo la conversión de lodos procedentes de la depuración de aguas residuales de matadero en un complejo bioestimulante. Los componentes bioestimulantes son: a) la biomasa de Bacillus licheniformis, que es una rizobacteria promotora del crecimiento vegetal (PGPR), y organismo encargado del proceso fermentativo, b) la secreción enzimática de dicho microorganismo, principalmente peptidasas y amidasas (50% ), implicadas en el metabolismo del N, y las glucanasas (33,3%), implicadas en el metabolismo de los hidratos de carbono, y c) la materia orgánica del lodo hidrolizado, compuesta en gran parte por péptidos y aminoácidos libres. El bioestimulante ha sido evaluado en suelo a nivel bioquímico y microbiológico. Indujo una fuerte estimulación microbiana del suelo y produjo la estimulación específica de las bacterias del suelo PGPR, que fue estudiada a través de un metabarcode. Además, principalmente al aplicar la fracción soluble del complejo bioestimulante, se encontró que el inóculo de Bacillus licheniformis permanece activo en el ambiente al final del experimento.

KOOLBIOCHAR - New formulations of Synthetic Black Soil for agricultural applications

Resumo A sobre-exploração do solo e as alterações climáticas colocam em risco a produção agrícola mundial. Isto é também verdade em Portugal, onde o clima e os solos pobres limitam a produtividade na agricultura. A resposta a este desafio global requer uma gestão sustentável da retenção da água, dos nutrientes e da matéria orgânica, bem como dos contaminantes que estão presentes ou que são transportados para os solos. Neste contexto surgiu o projeto KOOLBIOCHAR que visa desenvolver e avaliar a sustentabilidade de uma nova solução para os solos, que possa ser implementada a uma escala global, para mitigar os impactos dos desafios identificados. A solução do projeto KOOLBIOCHAR consiste na produção de um aditivo que permita a melhoria da performance dos solos agrícolas, de uma forma sustentável, através de produtos customizados de terra preta de síntese (TPS) à base de uma mistura de biocarvão de acácia e de resíduos orgânicos compostados. A ambição última do projeto é de contribuir para os desafios centrais das nossas sociedades, como os Objetivos de Desenvolvimento Sustentável (ODS) das Nações Unidas relacionados com a erradicação da fome (ODS2), com a ação climática (ODS13), com a sustentabilidade das cidades e das comunidades (ODS11), e com a proteção da vida terrestre (ODS15).

Abstract Soil overexploitation and climate change put the world agricultural production at risk. This is also true in Portugal, where the climate and poor soils limit agricultural productivity. Responding to this global challenge requires a sustainable management of water retention, nutrients and organic matter, as well as contaminants that are present in or are transported to soils. In this context, the KOOLBIOCHAR project emerged, aiming to develop and assess the sustainability of a new solution for soils, which can be implemented on a global scale, to mitigate the impacts of the above identified challenges. The solution of the KOOLBIOCHAR project consists in the production of an additive that allows the improvement of the performance of agricultural soils, in a sustainable way, through the development of customized products of synthetic black soils (TPS) based on a mixture of acacia biochar and composted organic wastes. The ultimate ambition of the project is to contribute to the central challenges of our societies, such as the United Nations Sustainable Development Goals (SDGs) related to the eradication of hunger (SDG2), climate action (SDG13), the sustainability of cities and communities (SDG11), and with the protection of terrestrial life (SDG15).

Seasonal dynamics of microbial biomass and enzymatic activities in Mediterranean agricultural soils: conventional vs. ecological management

Resumen Con el fin de reducir el impacto ambiental causado por los fertilizantes de origen mineral, el sector vitivinícola se dirige hacia un modelo sostenible. El uso de fertilizantes orgánicos es una práctica común en el avance hacia este modelo de gestión, aportando materia orgánica al suelo y repercutiendo en la mejora de las características físico-químicas y biológicas de éste. Además, también han de ser capaces de aportar el nitrógeno necesario para el correcto desarrollo del cultivo. Para comparar el efecto de un fertilizante mineral frente a un fertilizante orgánico en suelo, se realizó un seguimiento estacional de la cantidad de nitratos, y diferentes parámetros biológicos relacionados con el C y el N (carbono y nitrógeno de la biomasa microbiana, hidrólisis del diacetato de fluoresceína y las actividades β-glucosidasa y β-galactosidasa) en una parcela convencional y una ecológica en un viñedo comercial en Mallorca. Los resultados tras dos años de aplicación mostraron que el efecto de las aplicaciones (mineral y orgánica) provocaron tendencia a aumentar los valores de las variables biológicas gracias al aporte de nutrientes, siendo más notable el efecto del fertilizante mineral sobre su control.

Abstract To reduce the environmental impact caused by fertilizers of mineral origin, the wine sector is moving towards a sustainable model. The use of organic fertilizers is a common practice in the progress towards this management model, contributing to soil organic matter increase and impacting on the improvement of its physical-chemical and biological characteristics. Moreover, fertilizers must be capable of providing the necessary nitrogen for the correct crop growth. In order to compare the effect of a mineral fertilizer against an organic fertilizer in soil, a seasonal monitoring of the amount of nitrates and different biological parameters related to C and N (carbon and nitrogen of the soil microbial biomass, hydrolysis of diacetate of fluorescein and β-glucosidase and β-galactosidase activities) in a conventional plot and an organic plot in a commercial vineyard in Mallorca. The results after two years of application showed that the effect of the applications (mineral and organic) caused a tendency to increase the values of the biological variables thanks to the contribution of nutrients in soils, the effect of the mineral fertilizer on its control was greater.

Effect of composts from kiwi crop waste on lettuce growth

Resumo A compostagem realizada com estilha da poda e refugo de kiwi permite reciclar estes resíduos de modo a serem usados como corretivos orgânicos. No entanto, é necessário avaliar a resposta das culturas à aplicação destes compostados. Com este objetivo, foi realizado um ensaio de vasos com alface em blocos casualizados com a aplicação de compostados realizados com estilha da poda de kiwi e refugo de frutos de kiwi misturados nas proporções de 2:1, 1:1 e 1:2 (estilha:kiwi, p:p). Os tratamentos incluíram: (i) os compostados com 3 níveis de fertilização (10, 20 e 40 t ha-1); (ii) um adubo azotado (20,5% N) na dose de 50 kg ha-1 N; e (iii) um tratamento controle sem aplicação de fertilizante. O peso fresco da alface aumentou com a aplicação dos compostados em comparação com a aplicação de adubo azotado diminuindo os riscos de perdas de N. A produção de alface e a acumulação de N foram mais elevados com a aplicação de 40 t ha-1 de compostado com a proporção de 1:2 (estilha:kiwi, p:p) devido à maior disponibilidade de N mineral neste compostado com menos estilha e à maior quantidade de N mineralizado durante a experiência.

Abstract The process of composting pruning chips and kiwi fruit waste enable these wastes to be recycled as soil organic amendments. However, it is necessary to assess the crop response to the application of these composts. With this aim, a randomized block design pot experiment was set up with the application of composts from pruning chips and kiwi fruit waste mixed in proportions of 2:1, 1:1 e 1:2 (chips:kiwi, w:w). The treatments included: (i) composts with three rates (10, 20 e 40 t ha-1); (ii) mineral N fertilizer (20.5% N; at the dose of 50 kg ha-1 N); and (iii) a control treatment without soil amendments. Lettuce fresh weight increased with compost in comparison to mineral N fertilizer application, decreasing the risk of N losses. Lettuce production and N accumulation were higher with soil application of 40 t ha-1 of compost with 1:2 (chips:kiwi, w:w) due to the greater availability of mineral N in this compost with less chips and the greater amount of mineralized N during the experiment.

Effects of compost on lettuce (Lactuca sativa) yield and soil biochemical properties

Abstract Amended soils with compost produced from livestock effluents can increase soil fertility and crop productivity. The aim of this work was to assess the effect of the fertilization with a compost on the soil enzymatic activity and yield of a lettuce crop. An experiment was carried out under field conditions with the following treatments: control without fertilization; mineral N fertilization with 85 kg N ha−1 (Ni85); fertilization with compost in pellets (CP170N) at N dose of 170 kg ha−1; fertilization with CP at N dose of 85 kg ha−1 together with mineral N at 42.5 kg ha-1(CP85N+Ni42.5). The fertilization increased the lettuce biomass compared with the control treatment; the pelletized compost showed similar yields (P >0.05) than those obtained with the mineral N fertilization. The acid phosphatase and the total microbial biomass increased significantly in the soils fertilized with CP170N treatment. However, the alkaline phosphatase and (-glucosidase were similar between the treatments. The acidic pH of the soil may have decreased the alkaline phosphatase activity. The application of the pelletized compost at a dose of 170 kg N ha-1 showed the best agronomic behavior regarding the lettuce yield, the soil microbial biomass and the acid phosphatase activity.

Resumen Suelos enmendados con compost producido a partir de efluentes de ganado pueden aumentar la fertilidad del suelo y la productividad de los cultivos. El objetivo de este trabajo fue evaluar el efecto de la fertilización con compost sobre la actividad enzimática del suelo y el rendimiento de un cultivo de lechuga. Se realizó un experimento en condiciones de campo con los siguientes tratamientos: testigo sin fertilización; fertilización mineral N con 85 kg N ha−1 (Ni85); fertilización con compost en pellets (CP170N) a dosis de N de 170 kg ha−1; fertilización con CP a una dosis de N de 85 kg ha−1 junto con N mineral a 42.5 kg ha-1 (CP85N+Ni42.5). La fertilización incrementó la biomasa de lechuga en comparación con el tratamiento testigo; el compost peletizado mostró rendimientos similares (P >0.05) a los obtenidos con la fertilización con N mineral. La fosfatasa ácida y la biomasa microbiana total aumentaron significativamente en los suelos fertilizados con el tratamiento CP170N. Sin embargo, la fosfatasa alcalina y la β-glucosidasa fueron similares entre los tratamientos. El pH ácido del suelo puede haber disminuido la fosfatasa alcalina. La aplicación de compost peletizado a la dosis de 170 kg N ha-1 mostró el mejor comportamiento agronómico en cuanto al rendimiento de la lechuga, la biomasa microbiana del suelo y la actividad de la fosfatasa ácida.

Effects of using raw or treated pig slurry as substitutes of the basal fertilization of maize with mineral phosphate

Resumo A valorização agrícola de efluentes pecuários é considerada prioritária nas estratégias preconizadas na legislação (Portaria nº 79/2022). Porém, é importante evidenciar os méritos dessa estratégia em termos agrícolas, i.e., que a fertilização com materiais orgânicos pode ser feita sem perdas de produtividade e sem riscos para o solo, mas, também, criando soluções para reduzir os impactos ambientais (perdas de nutrientes para as águas e emissão de amoníaco). Este estudo pretende evidenciar que é possível fazer a aplicação de todo o P em fundo por via orgânica (140 kg P2O5/ha), suplementando o N por via mineral, de modo a fornecer a mesma quantidade total de N e P em todos os tratamentos orgânicos, sem excesso de P. Foi utilizado chorume de suíno, bruto ou tratado por separação sólido líquido e por acidificação (pH 5,0), de modo a avaliar qual o benefício destes tratamentos na disponibilização de N e P para a cultura do milho (Zea mays L.), num ensaio em vaso. A aplicação dos fertilizantes orgânicos, mais ricos noutros nutrientes essenciais, permitiu atingir um rendimento em biomassa e um crescimento da planta (altura e número de folhas) significativamente superiores aos obtidos por aplicação de adubação mineral (395 kg N/ha, 62 kg P2O5/ha, 150 kg K2O/ha), tendo os melhores resultados sido alcançados por aplicação do efluente bruto, do efluente acidificado, ou da fração líquida do efluente acidificado, evidenciando o benefício da acidificação na disponibilização de nutrientes para a cultura. É de realçar o facto de, apesar da concentração de P nas folhas e raízes da planta ter sido significativamente superior no controlo com adubação mineral, relativamente aos tratamentos orgânicos, a exportação total de P efetuado pelas plantas fertilizadas com efluentes pecuários foi, em termos absolutos, superior, ou idêntica, ao controlo com adubação mineral.

Abstract The agricultural valorization of animal slurries and manures is considered a priority and recommended in the legislation (Portaria No. 79/2022). However, it is important to highlight the merits of this strategy in agricultural terms, i.e., that fertilization with organic materials can be carried out without a reduction in productivity and endangering soil quality, but also creating solutions to reduce the environmental impacts (loss of nutrients to water and ammonia emissions). This study intends to evidence that it is possible to apply all the P via organic materials, as basal fertilization (140 kg P2O5/ha), with a supplementer N mineral application, to level the total amount of N and P provided by the organic fertilizers, avoiding excess P application. The study used raw pig slurry, and the materials obtained by its solid-liquid separation and acidification (pH 5.0), to evaluate the benefit of these treatments in the availability of N and P to maize (Zea mays L.), in a pot assay. The application of the organic fertilizers, richer in other essential nutrients, allowed achieving a biomass yield and plant growth (height and number of leaves) significantly higher than those obtained by applying the mineral fertilizer (395 kg N/ha, 62 kg P2O5/ ha, 150 kg K2O/ha), with the best results being achieved by applying the raw slurry, the acidified slurry, or the liquid fraction of the acidified slurry, evidencing the benefit of acidification in the availability of nutrients for the crop. It is worth noting the fact that, although the P concentration in the leaves and roots of the plant were significantly higher in the control with mineral fertilization, relatively to the organic treatments, the total P exported by the plants fertilized with the pig slurry derived fertilizers was, as an absolute value, higher, or identical, to the control with mineral fertilization.

Soil microbiome favors the performance of almond rootstock seedlings in co-cultivation with barrel medic

Abstract Soil microbiome influences plant growth and development. Moreover, crop co-cultivation practices have positive impacts on soil microbiome and function. In this study, soil microbiome from an almond field was collected to evaluate its effect on the growth of almond rootstock seedlings planted in pots with or without co-cultivation with Medicago truncatula. Four treatments were established: without legume and without microbiome (A); with legume and without microbiome (B); without legume and with microbiome (C) and with legume and with microbiome (D). After six weeks, no significant differences in culturable bacteria density in bulk soil or rhizospheric soil were found among treatments. Evapotranspiration rate per pot and day and plant growth, measured as increase in plant height per day, showed a similar tendency, with higher values found in non-inoculated plants in the first week of treatment, while, inoculated plants showed the highest values at the end of the experiment. M. truncatula co-cultivation increased pot evapotranspiration only in non-inoculated plants. Taken together these results suggest that the soil microbiome had a specific beneficial effect on the almond rootstock which could have negatively influenced the performance of M. truncatula.

Resumen El microbioma del suelo influye en el crecimiento y desarrollo de las plantas. Además, las prácticas de co-cultivo tienen impactos positivos en el microbioma del suelo y su función. En este trabajo, se recogió el microbioma del suelo de un campo de almendros para evaluar su efecto en el crecimiento del patrón de almendro GF-677 en macetas con o sin co-cultivo con Medicago truncatula. Se establecieron cuatro tratamientos: sin leguminosa y sin microbioma (A); con leguminosa y sin microbioma (B); sin leguminosa y con microbioma (C) y con leguminosa y con microbioma (D). Después de seis semanas, no se encontraron diferencias significativas en la densidad de bacterias cultivables en el suelo rizosférico y no rizosférico entre tratamientos. La tasa de evapotranspiración por maceta y día y el crecimiento de la planta fueron similares, con valores más altos inicialmente en plantas no inoculadas, mientras que, las inoculadas mostraron valores más altos al final del experimento. El co-cultivo con leguminosa aumentó la evapotranspiración en maceta sólo en plantas no inoculadas. En conjunto, los resultados sugieren que el microbioma tuvo un efecto beneficioso específico en el patrón de almendro. mientras que podría haber influido negativamente en el rendimiento de M. truncatula.

GO TECOLIVE - Effects of an organic compost on soil fertility and test plant development

Resumo Neste estudo, realizado no âmbito do Grupo Operacional “ Técnicas e tecnologia para valorização de subprodutos em olivicultura - TECOLIVE” - PDR 2020-101-031764, pretendeu-se testar a eficácia e segurança de um corretivo organico obtido por compostagem na própria exploração e utilizando os recursos existentes, com base em subprodutos do olival e efluentes de atividade pecuária, designadamente folhas e raminhos da limpeza da azeitona e estrume de ovelha. Os ensaios foram realizados em vasos, com dois solos de diferentes caraterísticas, considerando-se a dose recomendada de aplicação, a inexistência de efeitos fitotóxicos e a eficácia do produto diretamente sobre a fertilidade do solo e indiretamente sobre uma cultura teste, alface (Lactuca sativa L.). Para o efeito, além da quantificação dos resultados da aplicação de doses crescentes da matéria fertilizante sobre a produção de biomassa vegetal, foram também contempladas a análise da qualidade da matéria fertilizante em estudo e a avaliação do efeito sobre diversos parâmetros da fertilidade dos solos recetores. A aplicação de quantidades crescentes do composto orgânico conduziu a aumentos significativos da produção de biomassa e do diâmetro das plantas. Observou-se também uma melhoria da fertilidade do solo designadamente um aumento do teor de MO, do pH e do teor de fósforo, zinco e cobre extraíveis.

Abstract This study, conducted under the Operational Group "Techniques and technology for valorization of by-products in olive cultivation - TECOLIVE" - PDR 2020-101-031764, aimed to test the effectiveness and safety of an organic fertilizer obtained by composting at the farm and using existing resources, namely by-products of the olive grove and effluents from livestock activity, including leaves and twigs from olive cleaning and sheep manure. The tests were carried out in pots, with two soils with different characteristics, considering the recommended dose of application, the inexistence of phytotoxic effects and the effectiveness of the product directly on soil fertility and indirectly on a test crop, lettuce (Lactuca sativa L.). For this purpose, besides the quantification of the results of the application of increasing doses of the fertilizer on the production of vegetable biomass, the analysis of the quality of the fertilizer and the evaluation of the effect on several parameters of the fertility of the receiving soils were also contemplated.The application of increasing amounts of organic compost led to significant increases on the biomass and on the plants diameter, as well as an increase on soil parameters, MO, pH, and extratable phosphorus, zinc and copper.

Using a Portuguese regosol to derive soil reference values for arsenic

Abstract Soil reference values (SRV) are preliminary screening benchmark values used to evaluate the potential toxicity of specific contaminants in soils. The Portuguese Environmental Agency has proposed SRV for metals and metalloids based on soil uses but without consideration for the soil type. This project aims to derive SRV for arsenic (As) using a natural Portuguese soil since it is known that soil properties can influence the mobility and bioavailability of contaminants. To achieve this aim, a non-contaminated regosol was collected and spiked with a range of concentrations of As. After, a battery of ecotoxicological tests was performed using the spiked soil, including microbial parameters, reproduction with invertebrates, plant growth assays, and aquatic organisms (to evaluate elutriates from the spiked soil) following standard protocols (ISO and OECD) and aimed at deriving concentrations that cause a x% effect (ECx) to the tested organism and/or the test endpoints assessed. The endpoints will be used to estimate a SRV (e.g., PNEC- predicted no effect concentration to the ecosystem or HC5 - hazard concentration for 5% of the species of the ecosystem) using Species Sensitivity Distribution (SSD) models. The results showed that As was very toxic to all the tested organisms, and based on the data we collected, an HC5 based on 10% effect concentrations HC5 (EC10) of 2.80 mg kg-1 of soildw was proposed as SRV for regosol.

Resumo Os valores de referência do solo (VRS) são usados para avaliações preliminares da potencial toxicidade de contaminantes específicos presentes nos solos. A Agência Ambiental Portuguesa propôs VRS para metais e metalóides com base no uso potencial do solo, mas sem considerar o tipo de solo. Este trabalho tem como objetivo derivar VRS para o arsénio (As) usando um solo natural português, tendo por base o conhecimento de que as propriedades do solo podem influenciar a mobilidade e a biodisponibilidade de contaminantes. Para atingir este objetivo, um regossolo não contaminado foi recolhido e contaminado com uma gama de concentrações de As. Posteriormente, foi realizada uma bateria de testes ecotoxicológicos usando o solo contaminado e incluindo parâmetros microbianos, reprodução com invertebrados, ensaios crescimento e germinação de plantas, assim como ensaios com organismos aquáticos (para avaliação de elutriados do solo contaminado) seguindo protocolos padronizados (ISO e OCDE), de forma a determinar as concentrações que causam um efeito de X% nos organismos ou parâmetros testados (CE ou do Inglês ECx). Estes valores serão usados para estimar um VRS (por exemplo, PNEC - concentração para a qual não se prevê a ocorrência de efeitos no ecossistema ou HC5 - concentração de perigo (do inglês: Hazard Concentration) para 5% das espécies do ecossistema) usando curvas de distribuição da sensibilidade das espécies (do inglês: SSDs). Os resultados mostram que o As é muito tóxico para todos os organismos/parâmetros testados e, com base nos dados recolhidos, um HC5 baseado em concentrações de efeito de 10% HC5 (EC10) de 2,80 mg kg-1 de solops foi proposto como VRS para regossolos.

Agronomic and ecotoxicological assessment of Alentejo soils in irrigated sunflower plots

Resumo O desenvolvimento do regadio no Sul de Portugal tem acarretado benefícios positivos, permitindo a diversificação das culturas, a expansão e intensificação agrícola, e a melhoria económica da região. No entanto, esta mudança do uso do solo terra tem sido acompanhada pela intensificação de utilização de fatores de produção. Assim, o objetivo deste trabalho foi avaliar a qualidade de solos de duas parcelas de girassol regado (Girassol 1 (GR1) e Girassol 2 (GR2)), pertencentes à área do Empreendimento de Fins Múltiplos de Alqueva (EFMA) através de parâmetros agronómicos, ecotoxicológicos e análise de pesticidas. As amostras de solos foram recolhidas em duas fases distintas do ciclo vegetativo da planta, no período de março/abril (T1) e setembro/outubro (T2) de 2018. A análise dos resultados permitiu concluir que os solos apresentam pH ligeiramente alcalinos, com baixo teor de matéria orgânica e concentrações elevadas de macronutrientes. Os quantitativos de pesticidas foram superiores na parcela do GR2, amostras que promoveram uma maior toxicidade aos organismos-teste utilizados, nomeadamente no final do ciclo vegetativo. Os resultados evidenciam a importância de abordagens integradoras na avaliação da qualidade de solos agrícolas, o que permite o incremento da sustentabilidade agroambiental e uma melhoria na análise da saude dos solos.

Abstract The development of irrigation in the south of Portugal has brought positive benefits, allowing crop diversification, agricultural expansion and intensification, and economic improvement in the region. However, this change in land use has been accompanied by an intensification of the use of production factors. Thus, the objective of this work was to evaluate the soil quality of two irrigated sunflower plots ((Girassol 1 (GR1) and Girassol 2 (GR2)), belonging to the area of the Alqueva Multipurpose Development (EFMA) through agronomic, ecotoxicological parameters and pesticide analysis. Soil samples were collected in two distinct phases of the plant's vegetative cycle, in the period of March/April (T1) and September/October (T2) of 2018. The analysis of the results allowed to conclude that the soils present slightly alkaline pH, with low content of organic matter and high concentrations of macronutrients. The amounts of pesticides were higher in the GR2 plot, samples that promoted greater toxicity to the test organisms used, namely at the end of the vegetative cycle. The results show the importance of integrative approaches in assessing the quality of agricultural soils, which allows for an increase in agro-environmental sustainability and an improvement in the analysis of soil health.

Effect of the termination method of cover crops on soil microbiological parameters under two levels of irrigation

Resumen Los cultivos cubierta (CC) mejoran la sostenibilidad de los sistemas agrarios. El método de terminación puede afectar a los beneficios que proporcionan y este efecto puede ser modulado por la disponibilidad de agua. En un experimento en invernadero hemos evaluado la respuesta microbiológica del suelo a cuatro métodos de terminación de CC: Segado e incorporación, Glifosato, Roller Crimper, la combinación Glifosato+Roller Crimper y a un control sin CC, en combinación con dos niveles de riego, alto y bajo. A los 57 días tras la siembra del maíz se midió la respiración basal, respiración inducida por sustrato, carbono de la biomasa microbiana, cociente metabólico, cociente microbiano, hongos, bacterias y arqueas totales, ratio hongo/bacteria, longitud de micelio y colonización micorrícica. El nivel alto de riego acentuó las diferencias entre los métodos de terminación a nivel microbiológico. La incorporación de residuos fue el método más beneficioso en los dos niveles de riego. Los beneficios del roller crimper fueron mayores en alta disponibilidad de agua que en baja. Aunque la respuesta de los dos métodos con glifosato varió con el nivel de agua, su respuesta se mantuvo similar independientemente del nivel. El nivel de agua moduló la respuesta microbiológica del suelo a los métodos de terminación y debe ser considerado en su elección.

Abstract Cover crops (CC) improve the sustainability of agro-ecosystems. The CC termination method impacts the benefits they provide, and this effect could be modulated by water availability. In a greenhouse experiment we evaluated the soil microbiological response to four CC termination methods: Mowing and Incorporation (INC), Glyphosate (GLY), Roller Crimper (ROL), the combination Glyphosate+Roller Crimper (RGL) and a non-CC control (CON), in combination with two irrigation levels, high and low. At 57 days after maize seeding, soil basal respiration, substrate-induced respiration, microbial biomass carbon, metabolic quotient, microbial quotient, together with total fungi, bacteria and archaea, fungus/bacteria ratio, hyphal length, and mycorrhizal colonization were measured. The high level of irrigation enhanced the differences between the termination methods at microbial level. Residue incorporation was the most beneficial method at both irrigation levels. Roller crimper benefits were greater at high water availability than at low water availability. Although the response of the two methods with glyphosate varied with water level, their response remained similar regardless of the level. Water level modulated the soil microbiological response to the termination methods and should be considered in their choice.

Application of olive pomace biochar as soil amendment for intensive olive crops

Resumen La agroindustria del aceite de oliva es un importante sector económico en los países mediterráneos, cuya producción va acompañada de la generación de enormes cantidades de residuos orgánicos. La reciente proliferación de olivares superintensivos, más rentables, genera una mayor demanda de agua para riego y está aumentando la producción de estos residuos. La conversión de los residuos de almazara en biochar mediante pirólisis, para su posterior uso como enmienda orgánica en suelos de olivar superintensivo, podría contribuir a solucionar ambos problemas, ya que el biochar tiene una alta porosidad y contenido en carbono orgánico de alta estabilidad. Sin embargo, los efectos de su aplicación en las propiedades del suelo y en la fisiología del olivo no son bien conocidos. Este estudio aborda los efectos de la aplicación de biochar de alperujo de almazara, de compost vegetal (enmienda orgánica tradicional) y de la mezcla de ambos sobre las propiedades de un suelo (Xerochrept) y en la fisiología de olivos de “arbequina”. Esta plantación de olivar superintensivo y riego deficitario está situada en la estación experimental del IRNAS-CSIC "La Hampa" (Coria del Río, Sevilla, España). Tanto el biochar como el compost redujeron la resistencia a la penetración e incrementaron el contenido en Carbono orgánico y la humedad del suelo. La aplicación de biochar resultó más eficaz para aumentar la capacidad de retención de agua y la humedad del sueloy el estatus hídrico de los olivos en la fase anterior a la cosecha sin incrementar las tasas de respiración (emisión de CO2) del suelo.

Abstract The olive oil agro-industry is an important economic sector in Mediterranean countries, whose production is accompanied by the generation of huge quantities of organic waste. The recent proliferation of super-intensive olive groves, more profitable, generates a greater demand of water for irrigation and is increasing the production of organic waste. The conversion of these olive mill wastes into biochar by pyrolysis, for subsequent use as an organic amendment in super-intensive olive grove soils, could contribute to solving both problems, since biochar has a high porosity and a highly stable organic carbon content. Nevertheless, the effects of its application on soils properties and plant physiology are still not well known. This study addresses the effects of the application of olive mill pomace (alperujo) biochar, 100% vegetable compost (traditionally used organic amendment) and the mix of both organic amendments on the properties of a Xerochrept soil and on the physiology of “arbequina” olive trees”. The super-intensive olive trees plantation, with irrigation deficit, is located in the IRNAS-CSIC field station "La Hampa" (Coria del Río, Seville, Spain). Both biochar and compost reduced soil penetration resistance and increased soil organic Carbon and moisture content. However, the application of biochar was more effective than the addition of green compost or the compost+biochar mixture in increasing soil moisture. Biochar application improved soil physical properties and plant water status at the pre-harvest phase without increasing soil respiration (CO2 emission) rates.

Impact on global warming in the application of compost "alperujo" in aerobic rice cultivation

Resumen El cultivo tradicional de arroz (laboreo e inundación) es una de las fuentes antropogénicas más importantes en la emisión de gases de efecto invernadero (GEI), especialmente CH4 y N2O. Por tanto, es necesario desarrollar nuevas técnicas de manejo que puedan mitigar esta problemática. El objetivo del presente trabajo fue evaluar el efecto de los diferentes manejos en condiciones aeróbicas; laboreo (L) y su homólogo con compost (LC), no laboreo (NL) y su homólogo con compost (NLC), sobre el balance de CO2. Para ello, se realizó un experimento de campo con tres años de duración (2015-2017), donde se midieron, a lo largo del ciclo del cultivo, las emisiones de los GEI y los niveles de COT presente en los suelos. El potencial de calentamiento global (GWP) fue 1.19 veces superior en L con relación a NL. De manera que el balance neto entre emisiones y fijaciones en LC fue de 8.96 Mg de CO2 ha-1, siendo en L, NLC y NL de -7.37, -6.74 y -15.5 Mg de CO2 ha-1, respectivamente. Por tanto, la implantación de NL pueden ser una estrategia eficiente para contribuir a reducir el GWP y mejorar los balances netos de CO2 en el cultivo de arroz.

Abstract Traditional rice cultivation (tillage and flooding) is one of the most important anthropogenic sources of greenhouse gas (GHG) emissions, especially CH4 and N2O. Therefore, it is necessary to develop new management techniques that can mitigate this problem. The objective of the present work was to evaluate the effect of the different handlings in aerobic conditions; tillage (T) and its counterpart with compost (TC), non-tillage (NT) and its counterpart with compost (NTC), exert on the CO2 balance. To do this, a three-year field experiment (2015-2017) was carried out, where GHG emissions and TOC levels present in soils were measured throughout the crop cycle. The global warming potential (GWP) was 1.19 times higher in T compared to NT. So that the net balance between emissions and fixations in TC was 8.96 Mg of CO2 ha-1, being in T, NTC and NT -7.37, -6.74 and -15.5 Mg of CO2 ha-1, respectively. Therefore, the implementation of NT can be an efficient strategy to help reduce the GWP and improve the net balance of CO2 in rice crop.

Characterization of soil phosphorus in different land use over calcareous soils by chemical extraction methods and ³¹P-NMR spectroscopy

Abstract Many natural ecosystems around the world have been altered by human activities such as clearing for agriculture and pasture or timber harvesting. These land-use changes modify soil P status and dynamics. To evaluate the effects of land-use change on P chemical forms we used chemical fractionation and 31P-NMR spectroscopy. Soil samples were collected in calcareous moors in Castilla y León region (Spain) at 4 different depths and in three different land-use systems: natural holm-oak forest, affforested pine forest, and agricultural land. Our results indicated that land-use change from holm-oak forest to cereal crops increased orthophosphate P concentrations and P availability due to phosphate fertilization. However, soil phosphorus distribution in pine forest was similar to that in native oak forest.

Resumen Muchos ecosistemas naturales de todo el mundo han sido alterados por actividades humanas, como la tala para la agricultura y el pastoreo o la extracción de madera. Estos cambios en el uso del suelo modifican el estado y la dinámica del P del suelo. Para evaluar los efectos del cambio de uso del suelo en las formas químicas de P, utilizamos el fraccionamiento químico y la espectroscopia 31P-NMR. Se recogieron muestras de suelo en páramos calcáreos de la región de Castilla y León (España) a 4 profundidades diferentes y en tres sistemas diferentes de uso del suelo: encinar natural, pinar de repoblación y suelo agrícola. Nuestros resultados indicaron que el cambio de uso del suelo del bosque de encina a cultivos de cereal aumentó las concentraciones de ortofosfato y la disponibilidad de P debido a la fertilización con fosfato. Sin embargo, la distribución de fósforo en el suelo en el bosque de pino fue similar a la del bosque nativo de encina.

Removal of lanthanum and neodymium from soils applying the electrokinetic process

Resumo Os elementos de terras raras são matérias-primas essenciais para o desenvolvimento da sociedade. A produção dessas espécies ocorre maioritariamente pelo processo hidrometalúrgico e por adsorção por argilas. Contudo, esses métodos de produção resultam em grandes impactos ambientais, além do elevado consumo energético. Neste sentido, a busca por tecnologias verdes para extração desses elementos torna-se imprescindível. A eletromineração é uma técnica que utiliza o processo eletrocinético, assistido por eletrólitos “verdes”, para remoção de espécies metálicas de solos. O objetivo do presente trabalho foi avaliar o efeito de diferentes eletrólitos na remoção de lantânio e neodímio de solos, utilizando o processo electrocinético. Para isso, foram realizadas duas experiências variando o electrólito, a primeira com ácido cítrico e a segunda com ácido oxálico, ambos na concentração de 0.10 mol L-1. As eletrominerações foram conduzidas com uma intensidade de campo elétrico de 1.0 V cm-1 durante 240 h, usando 300 g de solo. Os resultados indicaram que a maior remoção ocorreu quando o ácido cítrico foi usado como eletrólito, apresentando uma extração de 63,2% para o lantânio e de 34,7% para o neodímio, com consumo elétrico de 12.6 W h. Assim, a técnica de eletromineração mostrou-se viável para a remoção de elementos de terras raras do solo, com baixo consumo energético.

Abstract Rare earth elements are critical raw materials, which are essential for the development of society. The production of these species mainly occurs via the hydrometallurgical process and ion adsorption clays. However, these processes result in high environmental impact and high energy consumption. In this sense, the search for green technologies to extract these elements becomes crucial. The electromining is a technique that applies electrokinetics using green electrolytes to assist in the removal of metallic species from soils. The aim of this work was to evaluate the effect of different electrolytes in the removal of lanthanum and neodymium from soils, applying the electromining technique. To that end, two experiments were conducted using different electrolytes, in one citric acid and in the other oxalic acid, both at a concentration of 0.10 mol L-1. The electromining experiments were conducted applying an electric field strength of 1.0 V cm-1 for 240 h using 300 g of soil. The results showed that the higher removal occurred using citric acid, which extracted 63.2% of lanthanum and 34.7% of neodymium, with an electric consumption of 12.6 W h. In light of this view, electromining showed to be a feasible technique to remove rare earth elements from soils with low energy consumption.

Field mobility of bispyribac-sodium herbicide under different rice crop management systems

Resumen El arroz aeróbico se ha propuesto como una práctica de gestión eficiente para ahorrar agua y mejorar la sostenibilidad del arroz como cultivo. Sin embargo, esta técnica influye significativamente en las propiedades del suelo y, por lo tanto, pueden modificar el comportamiento de los pesticidas. El Bispyribac-sodium (BYS) es un herbicida post-emergente que se usa con frecuencia en los agroecosistemas del arroz, pero que se considera muy tóxico para los organismos acuáticos y peligroso para el medio ambiente. Este trabajo persigue evaluar los efectos de la transición del sistema de riego por inundación al riego por aspersión en persistencia y movilidad en campo del BYS. Además, otra variable que se evaluó fue la aplicación de enmiendas orgánicas. La enmienda usada fue compost de alperujo subproducto agroindustrial (alperujo) del procesado de aceitunas (almazara). Para este propósito se realizaron experimentos de campo, implicando a seis tratamientos: Sin laboreo y riego por aspersión (SD) y el equivalente con aplicación de alperujo (SDC). Laboreo convencional y riego por aspersión (LC) y el equivalente con aplicación del alperujo (LCC) y laboreo convencional con inundación (LCI) y con incorporación de alperujo (LCIC). Las técnicas tradicionales en el cultivo del arroz (Laboreo convencional + inundación) benefician la movilidad en campo del herbicida BYS suponiendo un inconveniente para las aguas subterráneas frente a los suelos irrigados por aspersión. Además, el uso de alperujo podría considerarse como una estrategia para reducir contaminación de las aguas por BYS e incrementar su persistencia en las capas más superficiales del suelo, especialmente en sistemas de arroz aeróbico.

Abstract Aerobic rice has been proposed as an efficient management practice to save water and improve rice crop sustainability. However, this technique significantly influences the soil properties and, therefore, can modify the pesticides behavior. Bispyribac-sodium (BYS) is a post-emergence herbicide frequently used in rice agroecosystems but is considered highly toxic to aquatic organisms and dangerous to the environment. This work aims to evaluate the transition from flood irrigation to sprinkler irrigation effects on the persistence and field mobility of BYS. In addition, another variable evaluated was the application of organic amendments. The amendment used was olive pomace compost, an agro-industrial by-product (alperujo) of olive oil processing (almazara). For this purpose, field experiments were carried out, involving six different treatments: Without tillage and sprinkler irrigation (SD) and the equivalent with compost application (SDC). Conventional tillage and sprinkler irrigation (LC) and the equivalent with compost application (LCC) and conventional tillage with flooding (LCI) and with the compost incorporation (LCIC). Traditional techniques in rice cultivation (conventional tillage + flooding) benefit the mobility of the BYS herbicide in the field, assuming a disadvantage for groundwater quality when compared to soils irrigated by sprinklers. In addition, compost application could be considered a strategy to reduce water contamination by BYS and increase its persistence in the most superficial soil layers, especially in aerobic rice systems.

Digital Soil Mapping methods for monitoring edaphic parameters (Sentinel-2 and UAV) to support soil conservation and water management in vineyard plots

Resumo O solo constitui um recurso natural complexo e central para a produção agrícola e a qualidade ambiental dos agroecossistemas. O mapeamento e modelação detalhada das propriedades do solo por deteção remota permitem desenvolver ferramentas e conhecimento úteis para uma agricultura sustentável e responsável. Neste contexto, recolheram-se dados multiespectrais a partir do Sentinel-2 e de um veículo aéreo não tripulado (VANT), com sensor multiespectral RedEdge-MX acoplado. Desenvolveu-se um modelo digital de elevação (3D) para uma parcela de vinha na Região Demarcada dos Vinhos Verdes (Ponte de Lima, NW Portugal). A análise da superfície 3D e das bandas permitiu a produção de índices microtopográficos, litológicos, micro(bio)climáticos e edáficos espacialmente explícitos. Estes índices permitem, entre outros, representar e analisar a altitude, declive, exposição ao vento, carga térmica, evaporação de água do solo, albedo, carbonatos, óxidos de ferro e tipo de rocha. A integração dos dados obtidos neste trabalho com as análises ao solo realizadas pelo Institut Français de la Vigne et du Vin (2022), permitem a validação dos resultados e auxiliam nas decisões e ações operacionais de conservação do solo e de gestão hídrica em parcelas de vinha.

Abstract Soil is a complex and central natural resource for agricultural production and the environmental quality of agroecosystems. The mapping and detailed modeling of soil properties by remote sensing allow the development of useful tools and knowledge for sustainable and responsible agriculture. In this context, multispectral data were collected from Sentinel-2 and from an unmanned aerial vehicle (UAV), with a RedEdge-MX multispectral sensor coupled. A digital elevation model (3D) was developed for a vineyard plot in the Demarcated Region of Vinhos Verdes (Ponte de Lima, NW Portugal). The analysis of the 3D surface and the bands allowed the production of spatially explicit microtopographic, lithological, micro(bio)climatic and edaphic indices. These indices allow, among others, to represent and analyze altitude, slope, exposure to wind, thermal load, soil water evaporation, albedo, carbonates, iron oxides and rock type. The integration of the data obtained in this work with the soil analyzes carried out by the Institut Français de la Vigne et du Vin (2022), allows the validation of the results and helps in the decisions and operational actions of soil conservation and water management in vineyard plots.

Effect of olive-pomace based conditioners on soil aggregation stability: preliminary results from a micro-scale experiment

Resumo A aplicação de condicionadores ao solo visa o reforço da estabilidade da agregação (EA) e da sua resistência à erosão. O bagaço de azeitona (BA) húmido, proveniente da produção de azeite em duas fases, pode ser utilizado na compostagem e obtenção de condicionadores orgânicos (CBA). O trabalho tem como objetivo apresentar resultados de ensaio experimental realizado para avaliar a influência de CBA na EA. O ensaio comportou dois solos de potencialmente distinto grau de agregação (1, franco-limoso; 2, franco-argiloso), nos quais se aplicaram três CBA, em três doses. Amostras de agregados (1-2 mm) foram misturadas com condicionador moído (<0,75 mm), submetidas a ciclos diários de humedecimento e secagem, e coletadas em 5 momentos ao longo do período experimental de 30 dias. A EA foi determinada por agitação e crivagem em húmido. Confirmou-se a hipótese de o solo 2 possuir EA significativamente superior à do solo 1. Neste, a adição dos condicionadores aumentou significativamente a proporção de agregados estáveis relativamente ao solo original, em todas as dosagens, o que não se verificou no solo 2. A incorporação de CBA em solos cultivados com olival, contribuindo para a economia circular, melhora a proteção do solo pelo incremento de agregados estáveis.

Abstract The application of soil conditioners aims to reinforce aggregate stability (AS) and soil resistance to erosion. The wet olive pomace (OP), from olive oil production in two phases, can be used in composting and obtaining organic conditioners (OPC). The objective of this work is to present the results of an experiment carried out to evaluate the influence of OPC on AS. The experiment involved two soils of potentially different degrees of aggregation (1, silt loam; 2, clay loam), in which three OPC were applied, in three doses. Aggregate samples (1-2 mm) were mixed with conditioner (<0.75 mm), subjected to daily cycles of wetting and drying, and collected at 5 moments along the 30-day experimental period. AS was determined by shaking and wet sieving. The hypothesis that soil 2 has a significantly higher AS than soil 1 was confirmed. In this, the addition of conditioners significantly increased the proportion of stable aggregates as compared to the original soil, at all dosages, which was not observed in soil 2. The incorporation of OPC in soils cultivated with olive groves, contributing to the circular economy, improves soil protection by increasing stable aggregates.

Impact of prescribed fire on soil aggregate stability in shrub areas in Montesinho Natural Park, NE Portugal

Resumo O solo é um recurso indispensável para a manutenção da vida. No entanto, com o tempo, vem sofrendo impactos negativos capazes de reduzir a sua qualidade, comprometendo a manutenção dos ciclos naturais dependentes deste meio. Neste sentido, o fogo é considerado uma atividade que pode interferir com o estado de conservação do solo. Devido à utilização do fogo controlado em Portugal como ferramenta de gestão da vegetação, torna-se importante a realização de estudos que contribuam para o conhecimento dos seus efeitos no solo. Assim, o presente estudo teve como objetivo avaliar o impacto de um fogo controlado aplicado no Parque Natural de Montesinho, NE Portugal, na estabilidade da agregação do solo dois e sete meses pós-fogo, comparando com o solo original. As amostras foram coletadas em 11 pontos nas profundidades 0-3, 3-6, 6-10 e 10-20 cm ao longo de dois transetos, com aproximadamente 15 m de distância entre pontos e transetos. Após a avaliação da estabilidade da agregação, foram comparadas as condições do solo antes e depois do fogo. O fogo contribuiu para a redução da estabilidade da agregação ao longo do tempo e da profundidade do solo, mostrando os agregados de maiores dimensões menor estabilidade. Estes efeitos podem traduzir-se num aumento da erodibilidade do solo.

Abstract Soil is an indispensable resource for the maintenance of life. However, over time, it has undergone changes that may reduce its quality, compromising the maintenance of natural cycles dependent on this system. In this sense, fire is considered an activity that can interfere with the state of soil conservation. Due to the high use of controlled fire in Portugal as a vegetation management tool, it is important to carry out studies that contribute to the knowledge of its effects on the soil. Thus, the present study aimed to evaluate the impact of a controlled fire applied in the Montesinho Natural Park, NE Portugal, on the soil aggregate stability two and seven months after fire, compared to the original soil. Samples were collected in 11 points at depths 0-3, 3-6, 6-10, and 10-20 cm along two transects, with approximately 15 m of the distance between points and transects. After evaluating the aggregate stability, the soil conditions before and after the fire were compared. Fire contributed to the reduction of aggregation stability over time and soil depth, with larger aggregates showing less stability. These effects can translate into an increase in soil erodibility.

SOC stock in woody crops in Madrid Region depends on the soil conservation management

Abstract Cover crops or groundcovers in woody crops are a highly recommended conservation practice to protect soil against erosion and to increase soil organic carbon (SOC) stock. A study in southeastern Madrid Region was performed comparing plots under a soil conservation management (mechanically mowed, chemically mowed and no soil management) regarding tilling (total of 34 plots). This work was carried out from 2018 to 2021. Only plots under mechanically mowing significatively increased SOC stock comparing with nearby tilling plots (+4.9 Mg·ha-1). Plots managed chemically mowing or with no management due to weed scarcity did not increase SOC stock regarding their homologues tilled plots. Under the edaphoclimatic conditions of the study area, mechanically mowed plots reached 33.5 Mg SOC·ha-1 on average at 0-30 cm depth. This value is quite below regarding similar studies in other areas, showing the highly restricted edaphoclimatic conditions of the study zone.

Resumen Las cubiertas vegetales son una práctica muy recomendada para el manejo del suelo en cultivos leñosos, con el objeto de proteger el suelo frente a la erosión y aumentar el contenido de carbono orgánico que almacena. Un estudio en la zona sureste de la Comunidad de Madrid comparando parcelas con manejos alternativos al laboreo (cubierta vegetal segada mecánicamente, cubierta vegetal eliminada con herbicida y sin manejo debido a la escasa vegetación) frente a parcelas labradas fue llevado a cabo entre 2018 y 2021 (34 parcelas en total). Tan solo las parcelas con cubiertas vegetales segadas, incrementaron significativamente el contenido de carbono orgánico del suelo (SOC) frente a parcelas próximas labradas (+4.9 Mg·ha-1), mientras que las parcelas con cubiertas segadas con herbicida o las parcelas que no tenían manejo del suelo porque tenían escasa vegetación no tuvieron un contenido diferente de SOC frente a sus homólogas labradas. Bajo las condiciones edafoclimáticas de la zona de estudio, las parcelas con cubiertas segadas mecánicamente llegaron a almacenar de media 33.5 Mg SOC·ha-1 en el espesor de 0-30 cm, que es un valor menor que el de otros estudios similares en zonas diferentes, mostrando las importantes limitaciones edafoclimáticas de esta zona.

Ecotoxicological characterization of end-of-life organic substrate

Abstract In recent years the use of substrates in horticultural protected crops has been increasing. Their use presents several advantages including a more efficient use of water and nutrients and a reduction in the use of phytopharmaceutical products. However, at the end-of-life of these materials, their disposal is still a matter of continuous research and controversial discussion. Due to the high organic matter content of organic substrates (OS), the incorporation of these residues in agricultural fields could be advantageous. However, this practice requires a prior assessment of its environmental safety because of the risk of contamination and accumulation of bioactive molecules during cultivation cycles. The aim of this work was to make an ecotoxicological evaluation of one OS from soilless tomato production using standard protocols. A natural agricultural soil was amended with three increasing percentages of end-of-life OS (2.5, 5 and 10%). Effects of amended soils on seedling emergence and plant growth, earthworm reproduction rate and selected soil enzymatic activity were assessed. The preliminary results did not reveal major detrimental effects derived from the amendment of soil using end-of-life coconut substrate, at least for the percentages tested. In the future, more studies are necessary to evaluate possible impacts in freshwater resources.

Resumo Nos últimos anos a utilização de substratos para a produção de frutos e hortícolas em estufa tem vindo a aumentar. Estes materiais apresentam várias vantagens, nomeadamente um uso mais eficiente da água e dos nutrientes e a redução da aplicação de produtos fitofarmacêuticos. No entanto, o destino destes substratos no fim da sua vida útil é um assunto controverso que necessita de aprofundamento científico. Devido ao alto teor de matéria orgânica, a incorporação de substratos orgânicos (OS) em solos agrícolas poderá representar uma mais-valia. Porém, a segurança ambiental desta prática necessita de ser avaliada devido ao risco de acumulação de contaminantes e moléculas bioativas durante os ciclos de produção. Assim, este trabalho teve como objetivo efetuar uma avaliação ecotoxicológica de um OS em fim de vida, proveniente da cultura de tomate, através da realização de ensaios padronizados. Três percentagens deste resíduo foram incorporadas num solo agrícola natural (2.5, 5 e 10%), tendo sido testados os efeitos na germinação de sementes, crescimento de plantas, reprodução de oligoquetas e atividade enzimática dos solos. Os resultados preliminares não revelaram impactos negativos preocupantes para as concentrações testadas. De futuro, são necessários estudos mais abrangentes, nomeadamente para avaliar os possíveis efeitos ecotoxicológicos em matrizes aquáticas.

Plant-Nematode co-cultures in the screening of sustainable nematicides against soil-dweling parasitic nematodes of plants

Abstract The diseases caused by plant parasitic nematodes are still a serious constraint to modern global crop production. An increasing number of active compounds in commercial nematicidal formulations is being banned from use by common policies of pest management. Farmer communities report a low efficiency for the replacement pesticides, which reflects on crop yield and productivity. Novel sustainable biopesticides are urgently needed to cope with global food demands while respecting the most recent environmental policies. Plant-nematode co-cultures offer a stable biotechnological screening tool able to assess the active compound’s nematicidal activity and its effect on host tissues, simultaneously, in an easily accessible system that simulates natural infection. These systems are being developed and optimized at the Nematology laboratory of INIAV. Preliminary results were obtained for co-cultures of Solanum lycopersicum with the nematode Meloidogyne ethiopica and S. tuberosum with Globodera pallida. Future studies will target other plant parasitic nematodes, e.g., the root lesion nematodes (Pratylenchus penetrans) in transgenic roots of potato and the pinewood nematode (Bursaphelenchus xylophilus) on in vitro pine shoots (Pinus sp.).

Resumo As doenças causadas pelos nemátodes fitoparasitas permanecem uma considerável limitação á produção agrícola global. Um crescente número substâncias activas, utilizadas em formulações nematicidas comerciais, têm sido proibidas por políticas comuns de gestão de pragas, devido a preocupações ambientais e de saúde humana. Muitas vezes, os pesticidas de substituição demonstram uma menor eficiência no campo, o que se reflete num decréscimo do rendimento e da produtividade agrícola. O desenvolvimento de novos biopesticidas de alta eficiência para o combate de pragas e doenças das culturas é urgente e permitirá dar resposta adequada à crescente necessidade de produtos agrícolas, respeitando as novas políticas ambientais. As co-culturas planta-nemátode permitem uma despistagem simultânea da eficiência nematodicida de um composto e da sua influência nos tecidos vegetais do hospedeiro, num sistema facilmente acessível que simula a infecção natural. O laboratório de Nematologia do INIAV encontra-se a desenvolver estes sistemas e foram já obtidos resultados preliminares para as co-culturas de Solanum lycopersicum com o nemátode Meloidogyne ethiopica e S. tuberosum com Globodera pallida. Em ensaios futuros outros nemátodes fitoparasitas serão avaliados, como os nemátodes das lesões da raíz (Pratylenchus penetrans) em raízes transgénicas de batata e do nemátode da madeira do pinheiro (Bursaphelenchus xylophilus) em rebentos in vitro de pinheiro (Pinus sp.).

Effect of direct application of treated sludge on soil habitability: avoidance assays with Eisenia fetida

Resumo A crescente urbanização e industrialização promoveram um considerável aumento da produção de lamas de depuração que, no âmbito de uma economia circular, importa reciclar e valorizar sendo a aplicação ao solo uma alternativa viável, de baixo custo, devido ao respetivo valor fertilizante. A aplicação direta destes resíduos poderá potenciar riscos para a qualidade do solo uma vez que, em termos legais, para além dos elementos potencialmente tóxicos e microrganismos patogénicos, não considera os efeitos de outros potenciais contaminantes existentes. O objetivo deste trabalho é avaliar o efeito da aplicação direta de lamas de depuração, em diferentes doses (0, 2, 5 10, 15, 30 e 60 t/ha), na habitabilidade do solo, através da avaliação do comportamento da Eisenia fetida, com base em testes definidos pelas ISO. Os resultados obtidos evidenciam ausência de efeitos no comportamento da E. fetida em todas as doses estudadas (p>0,05), com uma percentagem de fuga negativa a variar entre os 40 e 60%, comparativamente ao controlo. Estes resultados estarão relacionados com os baixos teores de metais pesados e com a melhoria das condições fisíco-químicas do solo, resultando numa maior atratividade por parte do modelo biológico usado. Outros estudos, com outros solos, bioindicadores e métodos com maior tempo de exposição, serão necessários para validar a tendência observada.

Abstract The increasing urbanization and industrialization have promoted a considerable expansion in the production of sewage sludge, which it is important to recycle and valorise in the circular economy context, with soil application being a viable, low-cost alternative, due to its high fertilizing value. Tough the legal policies considered limit fixed quantities of heavy metals and pathogenic microorganisms, the direct application of these residues may potentiate risks to soil quality, since it does not consider the effects of different contaminants presence. The objective of this work is to evaluate the effect of direct application of sewage sludge, at different application rates (0, 2, 5 10, 15, 30 and 60 t/ha) on soil habitability, based on rapid tests defined by ISO guidelines, through the evaluation of the behaviour of Eisenia fetida. The results reveal no effects on the behaviour of E. fetida in all treatments studied with sewage sludge (p>0.05), with a percentage of negative avoidance varying between 40 and 60%, compared to the control group. These results are related to the low levels of heavy metals and to the improvement of the physical-chemical conditions of the soil, resulting in an increase attractiveness of the biological model used. Other studies, with other soils, bioindicators type and methodologies, with longer exposure time, will be necessary to validate the observed aptness.

Preliminary analysis of the bacterial community in different phases of the olive pomace composting process

Resumo O bagaço de azeitona (BA) é um subproduto húmido gerado na produção de azeite, com alta carga orgânica, e elevada toxicidade devido à sua composição em polifenóis. A sua produção pode, assim, constituir um problema ambiental para os países produtores de azeite, como Portugal. A compostagem poderá ser uma forma de valorizar este subproduto, sendo os microrganismos os principais agentes deste processo de degradação aeróbica. O objetivo do presente estudo foi estudar a evolução da comunidade bacteriana ao longo do processo de compostagem de BA e isolar e identificar bactérias com a finalidade de explorá-las no futuro como inóculos de compostagem. A compostagem foi realizada em quatro pilhas de escala industrial com diferentes proporções de BA, fonte de azoto, agente estruturante e reviramentos. Amostras compósitas foram coletadas nas pilhas em três momentos: fase inicial, fase mesófila e fase termófila. Os isolados bacterianos, obtidos através de diluições seriadas, foram identificados por sequenciação da região 16S do rRNA. Os resultados de composição e diversidade, mostraram diferenças significativas entre as fases de compostagem e entre pilhas, sugerindo uma mudança contínua de espécies bacterianas ao longo das diferentes fases do processo de compostagem do BA.

Abstract Olive pomace (OP) is a wet by-product generated in olive oil production, with a high organic load, and high toxicity due to its polyphenol composition. Its production can therefore be an environmental problem for olive oil-producing countries, such as Portugal. Composting may be a way to valorise this by-product, and the microorganisms are the main agents of this aerobic degradation process. The aim of the present study was to study the evolution of the bacterial community along the OP composting process and to isolate and identify bacteria with the purpose of exploring them in the future as composting inoculums. Composting was carried out in four industrial-scale piles with different proportions of OP, nitrogen source, structuring agent, and turnings. Compost samples were collected from the piles at three-time points: initial phase, mesophilic phase, and thermophilic phase. The bacterial isolates, obtained through serial dilutions, were identified by sequencing the 16S rRNA region. The results of composition and diversity, showed significant differences among the composting phases and among piles, suggesting a continuous change of bacterial species throughout the different phases of the OP composting process.

Soils of vineyards managed with spontaneous grass cover improve their ability to store organic carbon

Resumen La situación de pobreza endémica de carbono orgánico de los cultivos leñosos españoles es bien conocida. El laboreo excesivo mineraliza la materia orgánica y degrada los suelos agrícolas. El manejo mediante cubiertas vegetales puede sustituir al laboreo para aumentar el carbono orgánico del suelo, mejorar sus características y ser un sumidero más eficaz. Se presentan resultados de carbono orgánico oxidable y disuelto (COD) en un viñedo del centro España tras 10 años de manejo con laboreo y con cubiertas vegetales espontáneas segadas en calles alternas. Se estudian 3 capas del suelo, hasta 50cm de profundidad. Los cambios son evidentes en superficie, hasta unos 20cm, donde la materia orgánica aumenta desde 1.8 con laboreo hasta 2.5 % con cubiertas, también aumenta el COD, de 8.9 a 10.5 mg/L. No se han detectado diferencias significativas en las capas más profundas (35 y 50cm), pero se ha observado una tendencia clara a que el COD aumente en relación al contenido de carbono orgánico a 50cm. El desplazamiento del COD hacia horizontes más profundos se interpreta como una nueva ventaja de las cubiertas para mejorar la capacidad de secuestro de carbono a más largo plazo de estos suelos agrícolas.

Abstract The endemic scarcity of organic carbon in soils of Spanish woody crops is well known. Excessive tillage mineralizes organic matter and degrades agricultural soils. Soil management through grass covers can replace tillage and increase the soil organic carbon, leading to improvements of soil condition and acting as a more efficient carbon sink. Organic and dissolved carbon (DOC) results are presented in this work, in a vineyard located in the center of Spain; soils have been managed with alternate strips of tilled, and mowed spontaneous grass covers for the last 10 years. The study includes data from 3 soil layers, up to 50cm deep. Changes are evident in the upper layer, by 20cm, where organic matter increases from 1.8 in tilled soils to 2.5% in grassed soils; DOC also increases, from 8.9 to 10.5 mg/L. No significant differences have been detected in the deepest layers (by 35 and 50cm), however, a clear tendency has been observed for DOC to increase in relation to the organic carbon content at 50cm. The movement of DOC to deeper horizons is seen as a new advantage of the grass covers to improve the capacity of carbon sequestration in the long term of these agricultural soils.

Effects on soil of the application of compost in a super-intensive olive grove: organic residues and permanganate oxidizable carbon

Resumo A aplicação ao solo de subprodutos orgânicos compostados é uma medida paradigmática da Economia Circular. Apresentam-se resultados de 2 anos de um ensaio de aplicação de um compostado num olival superintensivo (var. “Cobrançosa”), em Monforte, Portalegre, com o objectivo de avaliar os efeitos a curto prazo nos resíduos orgânicos e na matéria orgânica do solo. O compostado foi produzido com estrume de ovinos e folhas e raminhos da limpeza das azeitonas. Foram aplicadas as dosagens T0 (0 kg m-2), T1 (2,5 kg m-2) e T2 (5,0 kg m-2) em blocos completos casualizados (3 tratamentos, 3 repetições, total de 9 talhões). Determinou-se a massa seca dos resíduos orgânicos (>1 mm) à superfície do solo e o carbono oxidável pelo permanganato de potássio (POX-C) em amostras de solo compostas das camadas 0-5, 5-15 e 15-30 cm. Dois anos após a aplicação (i) a massa de resíduos orgânicos à superfície do solo diminuiu para 1/3 a 1/2 do valor 5 meses após a aplicação, (ii) o POX-C na camada 0-15 cm é superior ao controlo, em especial no T2, o que indicia um aumento da matéria orgânica estável, (iii) os métodos usados permitiram detetar efeitos no solo, a curto prazo, resultantes da aplicação de compostado.

Abstract The application of composted organic by-products to the soil is a paradigmatic practice of the Circular Economy. Results of a 2-year trial of application of compost in a super-intensive olive grove (var. “Cobrançosa”), in Monforte, Portalegre, are presented, aiming to evaluate short-term effects on organic residues and soil organic matter. The compost was produced with sheep manure and leaves and sprigs from cleaning the olives. Application rates T0 (0 kg m-2), T1 (2.5 kg m-2) and T2 (5,0 kg m-2) were tested in complete randomized blocks (3 treatments, 3 replications, total of 9 plots). The dry mass at 65ºC of organic residues (>1 mm) on the soil surface and permanganate oxidizable carbon (POX-C) were determined in composite soil samples from layers 0-5, 5-15 and 15-30 cm. Two years after application (i) the mass of organic residues at the soil surface decreased to 1/2 to 1/3 of the value 5 months after application, (ii) POX-C in layer 0-15 cm is still higher than control, especially in T2, which suggests an increase in stable organic matter, (iii) the methods used allowed the detection of short-term effects on soil, resulting from compost application.

Pasture and livestock management effects on soil quality indicators in a dehesa of Extremadura

Resumen La dehesa (montado en Portugal) es un ejemplo de aprovechamiento sostenible de los recursos que puede estar amenazado por las malas prácticas de pastoreo. Este trabajo analiza el impacto que tiene la mejora de pastos y su aprovechamiento ganadero sobre indicadores de calidad del suelo. Se han estudiado dos parcelas S+ y S donde se ha llevado a cabo la siembra de leguminosas pratenses (en 2006 (S+) y en 2016 (S)) con pastoreo regenerativo. La parcela S- (control) no sembrada con pastoreo rotacional convencional, y por último simulando el abandono, (A) una parcela donde no hubo mejora de pastos y además no tiene aprovechamiento ganadero desde hace 8 años. El estudio bioquímico del suelo indicó una mayor actividad en las parcelas mejoradas con pastoreo regenerativo respecto a la abandonada. Las relaciones establecidas entre los indicadores estudiados con los parámetros fisico químicos más importantes, desde el punto de vista de la fertilidad del suelo, demostraron la dependencia del contenido en nutrientes con la actividad microbiana y viceversa. Este estudio ha puesto de manifiesto que el abandono de las dehesas sin aprovechamiento ganadero, puede resultar en una pérdida de fertilidad del suelo y la consecuente disminución de actividad microbiana asociada.

Abstract Dehesa (montado in Portugal) is an example of sustainable use of resources that may be jeopardized by improper grazing practices. This work analyzes the impact of pasture improvement and livestock management on soil quality indicators. Two plots S+ and S were studied where sowing of leguminous grasses was carried out (in 2006 (S+) and in 2016 (S)) and had regenerative grazing. Other plot S- (control) not improved by sowing legumes and with conventional rotational grazing, and finally simulating abandonment, (A) a plot where there was no pasture improvement and also has not had livestock exploitation for 8 years. The soil biochemical study indicated a higher activity in the improved plots with regenerative grazing compared to the abandoned plot. The relationships established between the indicators studied with the most important physical-chemical parameters, from the point of view of soil fertility, demonstrated the dependence of nutrient content on microbial activity and vice versa. This study has shown that the abandonment of pastures without livestock use can result in a loss of soil fertility and a consequent decrease in the associated microbial activity.

Effect of tillage on spontaneous ground cover composition in olive groves: preliminary results

Resumo O olival é uma cultura de elevada importancia na região de Trás-os-Montes, constituindo o olival tradicional o principal sistema de produção. A mobilização do solo para controlo de infestantes, é tradicionalmente, praticada nos olivais desta região, no entanto esta prática aumenta a susceptibilidade dos solos à erosão e pode perturbar a biota do solo e as suas interações. O conhecimento acerca do efeito desta prática cultural no coberto vegetal espontâneo do olival é escasso. Este estudo pretende elucidar os efeitos que a mobilização poderá provocar na diversidade e composição da vegetação espontânea de cobertura do solo em olival tradicional. Os resultados preliminares mostram que a mobilização do solo parece promover o aumento da abundância de espécies pertencentes às famílias Caryophyllaceae e Poaceae, e de limitar o desenvolvimento das famílias Asteraceae, Geraniaceae e Polygonaceae. Algumas destas famílias, em particular Poaceae e Asteraceae, contém espécies com reconhecido papel na atração de organismos auxiliares e, por conseguinte, são importantes fatores a ter em conta na gestão sustentável desta cultura.

Abstract The olive grove is a highly important crop in the region of Trás-os-Montes, being the traditional olive grove the main production system. Tillage for weed control is traditionally practiced in the olive groves of this region, however this practice increases soil susceptibility to erosion and can disturb soil biota and their interactions. Knowledge about the effect of this cultural practice on spontaneous vegetation cover in olive groves is scarce. This study aims to elucidate the effects that tillage may have on the diversity and composition of spontaneous ground cover vegetation in traditional olive groves. Preliminary results show that tillage seems to promote increased abundance of species belonging to the families Caryophyllaceae and Poaceae, and to limit the development of the families Asteraceae, Geraniaceae and Polygonaceae. Some of these families, in particular Poaceae and Asteraceae, contain species with recognized roles in attracting auxiliary organisms and are therefore important factors to consider in the sustainable management of this crop.

Organoclay granules as a sorbent to increase the persistence of the allelochemical scopoletin in soil

Resumen Los compuestos alelopáticos están recibiendo un gran interés como herbicidas respetuosos con el medio ambiente, pero su eficacia en el campo suele ser limitada debido a que generalmente presentan una escasa persistencia en los suelos. En este estudio se ha evaluado la incorporación en gránulos de organoarcilla como estrategia de protección del compuesto alelopático escopoletina frente a su rápida biodegradación en el suelo, con la finalidad de aumentar su persistencia y bioactividad. La cinética de adsorción de escopoletina en los gránulos de organoacilla fue más lenta comparada con la adsorción en el polvo de la misma y sugirió un proceso controlado por difusión intraparticular. Tras la incorporación de escopoletina en los gránulos de organoarcilla, la vida media del compuesto alelopático en un suelo agrícola mediterráneo aumentó de 0,34 a 14,4 días en condiciones de laboratorio y de 0,54 a 20,1 días en condiciones de campo, respecto al compuesto libre en disolución. Además, la incorporación en los gránulos de organoarcilla mejoró la la expresión de la fitotoxicidad de escopoletina en el experimento de campo, reduciendo la germinación y la longitud radicular de Lactuca sativa L. en mayor medida que el compuesto alelopático libre sin granular. Los resultados indican que la incorporación en gránulos de organoarcilla podría constituir una estrategia tecnológica eficaz para proteger a los compuestos alelopáticos de una rápida disipación en los suelos, aumentando su persistencia y mejorando su rendimiento en la protección de los cultivos.

Abstract Allelochemicals have been proposed as eco-friendly herbicides, but they often display a limited performance under field conditions because of a short persistence in soils. In this study, incorporation into organoclay granules was investigated as a strategy to protect the allelochemical scopoletin from rapid biodegradation processes and prolong its persistence and bioactivity in soil. A kinetic study revealed that the adsorption of scopoletin on the granules was slower than on the organoclay powder and indicated an intraparticle pore diffusion mechanism. After being incorporated into the organoclay granules, the half-life of scopoletin in a Mediterranean soil increased from 0.34 to 14.4 days under laboratory conditions, and from 0.54 to 20.1 days under field conditions, compared to the free compound. The granules also favored the expression of the phytotoxicity of scopoletin in the field experiment, reducing the germination and root growth of Lactuca sativa L. to a greater extent than the free, non-granulated allelochemical. The results of this work indicate that incorporation into organoclay granules could represent a suitable technological approach to protect allelochemicals from rapid dissipation losses in soil, which may help increase their persistence for a better performance as crop protection products.

Impact of maintenance techniques for woody crops (olive trees and vines) on the bacterial and fungal biomass of the soil, in the region of “Las Vegas of Madrid”

Summary The aim of this study was to evaluate the effect of different maintenance practices (tillage and mulching) applied in woody crops on soil parameters related to water availability and how these changes modulate the abundance of bacteria and fungi. The study was carried out in 24 farms (22 olive tree grovess and 2 vineyards) established in the Las Vegas de Madrid area. We carried out soil sampling at a 0-10 cm depth. We assessed chemical parameters (pH, total organic carbon -TOC-), physical parameters related to water availability (permanent wilting point -PMP-, macropores, mesopores, micropores, water stable aggregates WSA- and bulk density -BD-) and we quantified bacterial and fungal biomass. Then, we performed a multivariate analysis (Partial Least Squares Regression PLS-) to quantify the relationship between soil variables and bacterial and fungal biomass, The results indicate that the water availability in the soil (PMP) modulated the abundance of bacteria, while fungi, in contrast to bacteria, responded positively to soil carbon and negatively to BD. Our analyses indicate that, under these study conditions, bacteria were more sensitive to water availability while fungi were more sensitive to changes in soil compaction.

Resumen El objetivo de este estudio fue evaluar el efecto de las labores de mantenimiento (laboreo y mulching) utilizadas en cultivos leñosos sobre parámetros de suelo vinculados a la disponibilidad de agua y como estos cambios modularon la abundancia de bacterias y hongos. El estudio se realizó en 24 fincas (22 con olivos y 2 con viñas) establecidas en la comarca de Las Vegas de Madrid. Los muestreos de suelo se realizaron a una profundidad de 0-10 cm. Se cuantificó la biomasa bacteriana y fúngica, y se estimaron parámetros químicos (pH, carbono orgánico total total -TOC-) y físicos, relacionados con la disponibilidad de agua en el suelo (punto de marchitez permanente -PMP-, macroporos, mesoporos, microporos, agregados estables al agua -WSA- y densidad aparente -BD-). Para cuantificar la relación de las variables edáficas con la biomasa bacteriana y fúngica se realizó un análisis multivariado (Regresión por Mínimos Cuadrados Parciales -PLS-). Los resultados señalan que la disponibilidad de agua en el suelo (PMP) moduló la abundancia de bacterias, mientras que los hongos, a diferencia de las bacterias, respondieron positivamente al carbono del suelo y negativamente a BD. En general podemos decir que, bajo estas condiciones de estudio, las bacterias fueron más sensibles a la disponibilidad de agua mientras que los hongos lo fueron a cambios en la compactación suelo.

Glomalin-related soil protein evolution after prescribed burning of scrub in mountain soils (Central Pyrenees, NE-Spain)

Resumen Se evalúan los efectos de la quema prescrita de matorral sobre el suelo a corto plazo, a los 5 y a los 9 años usando como indicadores las fracciones de glomalina. Dicha evaluación se efectúa para tres espesores (0-1, 1-2 y 2-3 cm) de suelo y por cuatriplicado en cada momento de muestreo. Los valores de glomalina (total, residual y lábil) aunque son más elevadas, en valor absoluto, en el cm del suelo más superficial, raramente muestra diferencias significativas en profundidad. Inmediatamente tras la quema, los suelos duplican su contenido en glomalina total y residual con respecto a los suelos control o no quemados; dichos valores disminuyen con el tiempo. La glomalina lábil, que no se ve significativamente afectada justo tras la quema, se reduce a la mitad pasados los años. En definitiva, se identifican una serie de cambios en las diferentes fracciones de glomalina, a pesar de la baja severidad de este tipo de quemas.

Abstract The effects of prescribed burning of bushes on the soil are evaluated in the short term, at 5 and 9 years, using glomalin fractions as indicators. This evaluation is carried out for three soil thicknesses (0-1, 1-2 and 2-3 cm) and in quadruplicate at each sampling time. The glomalin values (total, residual and labile), although higher, in absolute value, in the shallowest cm of soil, rarely show significant differences in depth. Immediately after burning, soils double their total and residual glomalin content with respect to control or unburned soils; these values decrease with time. Labile glomalin, which is not significantly affected immediately after burning, is reduced by half after a few years. In short, a series of changes in the different glomalin fractions are identified, despite the low severity of this type of burning.

Cover crops for the improvement of soil microbiological properties in intensive horticultural production systems

Abstract The production of horto-industrial crops in the Portuguese region of Ribatejo is based on monoculture systems with high technical intervention, which results in soil biodiversity imbalances, loss of fertility and progressive degradation. In these systems, the introduction of cover crops preceding the main crop of the agricultural year can contribute to improving the soil status and the sustainability of the production systems. The present work describes the evaluation of soil microbiological indicators in two field trials in Ribatejo, where different cover crops were installed: biodiverse mixture of legumes and grasses, including clovers inoculated with rhizobia; annual ryegrass (Lolium multiflorum); and forage turnip (Raphanus sativus) for biofumigation. Control plots without cover crops were maintained in both fields. The evaluations focused on soil enzymatic activities (dehydrogenase, alkaline phosphatase and β-glucosidase) and several groups of microorganisms, including total bacteria, symbiotic nitrogen-fixing bacteria (rhizobia), free-living nitrogen-fixing bacteria, phosphate-solubilizing bacteria and phytostimulating microorganisms. The results indicated a tendency for the increase of soil microbiological activity and beneficial microorganisms with cover crops, especially with the biodiverse mixture of legumes and grasses and annual ryegrass.

Resumo A produção de culturas hortoindustriais na região do Ribatejo assenta em sistemas de monocultura com elevada intervenção fitotécnica, o que resulta em desequilíbrios de biodiversidade, perda de fertilidade e degradação progressiva dos solos. Nestes sistemas, a introdução de culturas de cobertura no período que antecede a cultura principal do ano agrícola pode contribuir para melhorar o estado do solo e a sustentabilidade da produção. O presente trabalho descreve a avaliação de indicadores microbiológicos do solo em dois campos piloto no Ribatejo, onde foram instaladas diferentes culturas de cobertura: mistura biodiversa de leguminosas e gramíneas, incluindo trevos inoculados com rizóbios; azevém anual (Lolium multiflorum); e nabo forrageiro (Raphanus sativus) para biofumigação. Em ambos os campos foram mantidos talhões-controlo, sem culturas de cobertura. As avaliações incidiram sobre atividades enzimáticas do solo (desidrogenase, fosfatase alcalina e β-glucosidase) e vários grupos de microrganismos, incluindo bactérias totais, bactérias fixadoras de azoto simbióticas (rizóbios), bactérias fixadoras de azoto de vida livre, bactérias solubilizadoras de fosfato e microrganismos fitoestimulantes. Os resultados indicaram uma tendência para o aumento da atividade microbiológica do solo e de microrganismos benéficos com as culturas de cobertura, em especial com a mistura biodiversa de leguminosas e gramíneas e com azevém anual.

Modeling the 3-PG fertility rating as a function of soil physical and chemical characteristics

Resumo Os modelos de base fisiológica são ferramentas científicas úteis, mas não têm sido usados frequentemente na gestão florestal, pois exigem dados detalhados de entrada e não fornecem os resultados necessários para a gestão. O 3-PG (Physiological Principles in Predicting Growth) é um modelo de base fisiológica desenvolvido com a intenção de fazer a ponte entre os modelos empíricos e os modelos de base fisiológica mais complexos. A fertilidade do solo é considerada por meio de um índice de fertilidade, o chamado FR (fertility rating), valor que varia entre 0 e 1, atribuído empiricamente de acordo com as características do local. Embora haja um conhecimento limitado da relação que existe entre o FR e propriedades do solo, alguns esforços têm sido feitos para desenvolver funções relacionando o FR e as características do solo. O presente estudo procura desenvolver um modelo geral para prever o FR a partir das características do solo e testar a possibilidade de fazer o modelo 3-PG sensível a fertilizações. Os resultados preliminares originaram modelos com um bom desempenho ao nível da parcela, mas a primeira tentativa de modelo generalizado não alcançou uma boa capacidade preditiva. Os testes continuam a decorrer de maneira a melhorar a capacidade preditiva dos diferentes modelos.

Abstract Process based models are useful scientific tools, but they have not been used frequently in forest management, as they require detailed input data with scarce results for management. The 3-PG (Physiological Principles in Predicting Growth) is a process-based model developed with the intention of bridging the gap between the empirical models and the more complex physiologically based models. Soil fertility is considered through a fertility index, the so-called FR (fertility rating), a value that varies between 0 and 1, empirically attributed according to the characteristics of the place. Although there is limited knowledge of the relationship that exists between FR and soil properties, some efforts have been made to develop functions relating FR and soil characteristics. The present study seeks to develop a general model to predict FR from soil characteristics and to test the possibility of making the 3-PG model sensitive to fertilization. Preliminary results resulted in models with good performance at the plot level, but the first attempt at a generalized model did not achieve good predictive capacity. Tests continue to take place to improve the predictive capacity of the different models.

Vermicomposting of substrates with sewage sludge: effects on Eisenia fetida

Resumo A valorização das lamas de ETAR na agricultura como fonte de matéria orgânica e nutrientes tem vindo a ganhar relevo. Estes resíduos, produto do tratamento de águas residuais, podem ser melhorados através de bioprocessos como a vermicompostagem, ultrapassando limitações tais como a estabilidade da matéria orgânica e/ou presença de contaminantes. Com o objetivo de melhor compreender a viabilidade da vermicompostagem de lamas de ETAR efetuou-se um ensaio com substratos contendo proporções variáveis deste resíduo, de estrume de equino maturado e de casca de arroz. Aos diferentes substratos, sujeitos a um período de pré-compostagem, adicionaram-se minhocas adultas da espécie Eisenia fetida por um período de 31 dias. O efeito nas minhocas da exposição às diferentes misturas foi avaliado ao nível da mortalidade, crescimento e reprodução. Os resultados revelaram que substratos com propoções elevadas de lamas de ETAR são letais para as minhocas e que a exposição às lamas inibe a reprodução desta espécie. O pH, condutividade eléctrica e razão C/N foram as características dos substratos que sugerem um maior impacto nos resultados obtidos e a ter em principal consideração em estudos futuros.

Abstract The valorization of sewage sludge as a source of organic matter and nutrients in agriculture has been gaining importance. These residues, a product of wastewater treatment, can be improved through bioprocesses such as vermicomposting, overcoming limitations such as the stability of organic matter and/or the presence of contaminants. In order to better understand the viability of vermicomposting of sewage sludge, a trial was carried out with substrates containing varying proportions of this residue, of matured horse manure and of rice husk. Adult earthworms of the Eisenia fetida species were added to the different substrates, previously pre-composted for a period of 31 days. The effect of exposing the earthworms to the different mixtures was evaluated in terms of mortality, growth and reproduction. The results revealed that high amounts of sewage sludge are lethal to earthworms and exposure to the sludge inhibited this species reproduction. The pH, electrical conductivity and C/N ratio were the characteristics of the mixtures that suggest a greater impact on the results obtained and to be considered in future studies.

Distribution of microbial biomass in a vineyard soil in the Vinhos Verdes region

Resumo A compreensão da distribuição do carbono da biomassa microbiana (CBM) metabolicamente ativa nos solos vitícolas é fundamental para determinar o balanço de carbono em viticultura sustentável e para integrar estas determinações em análises de rotina que permitam avaliar o impacto de práticas de gestão sustentável do solo. O carbono da biomassa microbiana foi determinado em três datas correspondentes aos estados fenológicos de floração, bago de ervilha e maturação, na linha e na entre linha de uma vinha da casta Loureiro sujeita a diferentes estratégias de rega, e num solo natural considerado controlo. Neste trabalho foi possível observar diferenças entre o CBM de um solo vitícola e um solo natural. No solo vitícola, os maiores valores de biomassa microbiana foram registados na fase fenológica de bago de ervilha, coincidente com o início da rega. Em parte, registaram-se maiores valores de biomassa microbiana na linha que na entre-linha.

Abstract Understanding the carbon distribution of metabolically active microbial biomass (MCB) in viticultural soils is essential to determine the carbon balance in sustainable viticulture and to integrate these determinations into routine analyzes that allow assessing the impact of sustainable soil management practices. The microbial biomass carbon was determined on three dates corresponding to the phenological stages of flowering, pea berry and maturation, in and between rows of a Loureiro grapevine subject to different irrigation strategies, and in a natural soil considered as a control. In this work it was possible to observe differences between the MCB of a viticultural soil and a natural soil. In viticultural soil, the highest values of microbial biomass were recorded in the pea berry phenological phase, coinciding with the beginning of irrigation. In part, higher values of microbial biomass were recorded in the row than in the inter-row.

Conservation Agriculture: Impact on the Dissipation of Herbicides

Resumen La acumulación de restos vegetales en la superficie de suelo (mantillo) y el no laboreo del suelo representan una práctica agrícola de conservación del suelo frecuente que puede modificar la disipación de los herbicidas que se aplican en estos sistemas agrícolas. El objetivo de este trabajo fue estudiar a escala de campo: i) la disipación de los herbicidas S-metolacloro (SMOC), foramsulfuron (FORAM) y tiencarbazona-metil (TIEN), ii) la formación de metabolitos, y iii) la actividad deshidrogenasa (DHA) del suelo bajo prácticas de laboreo tradicional (LT) y de conservación (NL) en un suelo agrícola con dos contenidos diferentes en carbono orgánico (CO) superficial (S1 y S2). La disipación de los herbicidas fue más rápida en los suelos con NL que en los suelos LT teniendo lugar mayoritariamente en la superficie del mantillo. Los tiempos de vida media (DT50) bajo los diferentes tratamientos variaron entre 1,7-30,2 (SMOC), 3,7-8,8 (FORAM) y 5,2-25,2 (TIEN) días. La menor cantidad de metabolitos observada en los suelos bajo NL coincidió con la menor cantidad de herbicidas que llegó a la superficie de estos suelos resultado de su interceptación parcial por el mantillo. La DHA fue mayor en los suelos no tratados con herbicida y bajo NL.

Abstract The accumulation of crop residues on the soil surface (mulch) and no-tillage of the soil represent a current agricultural practice for soil conservation that can modify the dissipation of herbicides applied in these agricultural systems. The objective of this work was to study at field scale: i) the dissipation of the herbicides S-metolachlor (SMOC), foramsulfuron (FORAM) and thiencarbazone-methyl (TIEN), ii) the formation of metabolites, and iii) the soil dehydrogenase activity (DHA) under traditional (LT) and conservation (NL) tillage practices in an agricultural soil with two different surface organic carbon (CO) contents (S1 and S2). Herbicide dissipation was faster in NL than in LT soils, taking place mainly on the mulch surface. The half-lives (DT50) under the different treatments varied between 1.7-30.2 (SMOC), 3.7-8.8 (FORAM) and 5.2-25.2 (TIEN) days. The lower amount of metabolites observed in the soils under NL agreed with the lower amount of herbicides that reached the soil surface as a result of their partial interception by the mulch. Soil DHA was higher in soils untreated with herbicide and under NL.

Rehabilitation of sulfide tailings through designed Technosol and microbial-inoculant

Abstract The implementation of pastures or herbaceous intercropped with non-food autochthonous plants to extract high-added value compounds is a promising option for improving both the environmental and the economic sustainability of the active mining areas. The continuous generation of acid mine drainage and the physico-chemical characteristics of sulfide tailings make impossible the germination and development of plant covers, and therefore, an essential step in the environmental rehabilitation is the physico-chemical improvement of these materials. This study assessed, in a batch assay, the acid neutralization capacity of a designed Technosol applied to sulfide tailings at differentes applications rates. The best proportion was used subsequently in microcosm assay under greenhouse conditions, where herbaceous species were sown. Three treatments were established: sulfide tailings with a microbial inoculant (MI); Technosol+sulfide tailing with and without MI. The MI included a micorrhizal fungi +Trichoderma. In sulfide tailings with the MI no germination occurred. Significant improvement of physico-chemical properties of the sulfide tailing and their leachates were obtained with Technosol application (e.g. increase of fertility and pH, decrease of the contaminants available fraction). The Technosol also allowed the develpoment of a vigourous herbaceous cover without visual phytotoxic symptoms that can valorize the mining areas through a new land use. The production of herbaceous biomass was similar designed Technosol with or without MI.

Resumo A implementação de pastagens ou intercropping de herbáceas com plantas autóctones não alimentícias para depois extrair compostos de valor acrescentado uma opção promissora para melhorar a sustentabilidade ambiental e económica de áreas mineiras em actividade. A contínua geração de drenagem ácida e as características físico-químicas das escombreiras de sulfuretos impossibilitam a germinação e o desenvolvimento das coberturas vegetais logo, uma etapa essencial na reabilitação ambiental é a melhoria físico-química destes materiais. O presente estudo avaliou, num ensaio de batch, a capacidade de neutralização de ácidos de um Tecnossolo aplicado, a diferentes proporções, a materiais de uma escombreira de sulfuretos. A melhor proporção usou-se posteriormente num ensaio em microcosmo em estufa, onde se semearam espécies herbáceas. Realizaram-se três tratamentos: Escombreira com inóculo microbiano; Tecnossolo+escombreira com e sem inóculo microbiano. O inóculo microbiano incluiu um fungo micorrízico+Trichoderma. Na escombreira com inóculo microbiano não ocorreu germinação. Significativas melhorias nas características físico-químicas da escombreira e seus lixiviados obtiveram-se com a aplicação do Tecnossolo. O Tecnossolo também permitiu o desenvolvimento de uma vigorosa cobertura herbácea sem sinais visiveis de fitotoxicidade, que pode valorizar a área mineira através de um novo uso do solo. A produção de biomassa foi semelhante com e sem inóculo microbiano na Escombreira com Tecnossolo.

Nature based solutions for soil restoration in Vitoria-Gasteiz (Spain). The Phy2Sudoe case

Resumen Al oeste de Vitoria-Gasteiz existen zonas industriales cuyo rápido crecimiento provocó la fragmentación ecológica del territorio circundante. La zona de trabajo (Mendebaldea, 30 ha) se encontraba en estado de abandono y con suelos contaminados antes de la intervención, lo que impedía su uso público y cualquier actividad. Desde el Ayuntamiento de Vitoria-Gasteiz, la Universidad del País Vasco y el Centro de Investigación Neiker-Tecnalia se propuso la restauración del ámbito mediante el empleo de soluciones basadas en la naturaleza para crear una gran infraestructura verde que aportase diversos beneficios ambientales: mitigación del cambio climático, la recuperación de los suelos y la mejora del paisaje. El proyecto se desarrolló en 6 años (10 hectáreas restauradas cada 2 años) incluyendo: sumideros de carbono en suelo y bosques mediante enmiendas orgánicas y plantaciones, balsas artificiales para la biodiversidad, filtros verdes de aguas y red de caminos. Para la descontaminación de suelos se recurrió a la fitorremediación combinando enmiendas y sistemas agroforestales en el marco de los proyectos europeos PhytoSudoe y Phy2Sudoe. Las parcelas de ensayo ejecutadas en dichos proyectos van siendo monitorizadas a largo plazo con participación del público, ofreciendo así un espacio demostrativo para el aprendizaje de estas técnicas de recuperación de suelos.

Abstract Industrial areas located in the west of Vitoria-Gasteiz caused ecological fragmentation in the territory due to their rapid urban growth. The area of work (Mendebaldea 30 ha) had derelict and polluted soils before the intervention, lacking of any public use or activity. The Vitoria-Gasteiz City Council, the University of the Basque Country and the Neiker-Tecnalia Research Center proposed the restoration of the area by using nature-based solutions to create a large green infrastructure that would provide several environmental benefits such as climate change mitigation, soil recovery and landscape restoration. The project was developed over 6 years (10 hectares restored every 2 years) including: soil and forest carbon sinks through organic amendments and plantings, artificial ponds for biodiversity, green water filters and pathways network. For soil decontamination, phytoremediation was used combining organic amendments and agroforestry systems due to the participation in the European phytoremediation projects PhytoSudoe and Phy2Sudoe. The project test plots are being monitored in the long term with the help of public participation, offering a demonstration space for learning new soil remediation techniques.

Water level modulates the soil microbial response to elevated tropospheric ozone in wheat

Resumen El nivel de agua modula el impacto del ozono troposférico sobre la planta, aunque se desconoce hasta qué punto este efecto se traslada a la microbiota del suelo. Se ha investigado si la disponibilidad de agua puede alterar la respuesta microbiana a elevadas concentraciones de ozono en una variedad de trigo sensible al ozono. Se estableció un ensayo con cámaras de techo descubierto con cuatro niveles de ozono (Preindustrial; Actual; Actual+20 ppb; Actual+40 ppb) y dos niveles del riego (estrés y óptimo). La fracción rizosférica del suelo (0-5 cm) mostró mayor sensibilidad al nivel de ozono y de riego que la fracción de resto (“bulk”). El aire Actual fue el tratamiento menos sensible, y el Actual+20 el más sensible al riego. Independientemente del nivel de riego, el aire Actual y Actual+40 mostraron características microbiológicas bien contrastadas. El estrés hídrico altera el comportamiento intermedio de Actual+20 aumentando su cociente metabólico. El aire Preindustrial tendió a comportase como Actual+20 en ambos niveles de riego (menor qMic y mayor qCO2), por lo que cambios de ozono con respecto al Actual provocan una menor eficiencia en el uso del C. El riego modula el efecto del ozono sobre la microbiota del suelo.

Abstract Water level modulates the tropospheric ozone impact on the plant, although the extent to which this effect is transferred to the soil microbiota is unknown. We investigate whether water availability can alter the microbial response to elevated ozone concentrations in an ozone-sensitive wheat variety. An open-top chamber trial was set up with four ozone levels (Pre-industrial; Ambient; Ambient+20 ppb; Ambient+40 ppb) and two irrigation levels (stress and optimum). The rhizosphere fraction of the soil (0-5 cm) showed higher sensitivity to ozone and irrigation level than the bulk fraction. Ambient air was the least sensitive treatment, and Ambient+20 was the most sensitive to irrigation. Regardless of the irrigation level, Ambient and Ambient+40 air showed contrasting microbiological characteristics. Water stress alters the intermediate behaviour of Ambient+20 by increasing its metabolic quotient. Pre-industrial air tended to behave like Ambient+20 at both irrigation levels (lower qMic and higher qCO2), so changes in ozone with respect to Ambient lead to lower efficiency of C use. Irrigation modulates the effect of ozone on soil microbiota.

InfiAsper: a rainfall simulator with varying precipitation intensity to assess soil erosion

Abstract Research involving the use of rain simulators dates to 1930. Since then, the evolution of this equipment has made it increasingly accessible, practical, and accurate. Its applications include the assessment of the impacts of water erosion on soil degradation as a function of land use and occupation and the rate of water infiltration into the soil. The reproduction of the rainfall pattern by varying the intensity of precipitation is one of the main limitations of the use of simulators. However, the recent modification in InfiAsper (Macedo et al., 2021) allows instantaneous varying the intensity of rainfall application and provides high uniformity in rainfall of different patterns.

Resumo As pesquisas envolvendo o uso de simuladores de chuva datam de 1930. Desde então, a evolução desse equipamento o tornou cada vez mais acessível, prático e preciso. Suas aplicações incluem a avaliação dos impactos da erosão hídrica na degradação do solo em função do uso e ocupação do solo e da taxa de infiltração da água no solo. A reprodução do padrão pluviométrico variando a intensidade da precipitação é uma das principais limitações do uso de simuladores. No entanto, a modificação recente no InfiAsper (Macedo et al., 2021) permite variar instantaneamente a intensidade de aplicação das chuvas e proporciona alta uniformidade nas chuvas de diferentes padrões.

Mediterranean salt steppes in Alentejo and Extremadura: Environment, threats and conservation

Resumen La protección de los ecosistemas es garantía de la sostenibilidad de las actividades humanas. La presencia de hábitats excepcionales en el suroeste de la península Ibérica es frecuente, resultando imprescindible su estudio y conservación. Este es el caso de las estepas salinas mediterráneas de interior, siendo descritas en pequeñas extensiones de Alentejo y Extremadura. Su estudio, correcta interpretación y conservación deben ser prioritarios, como así es considerado este hábitat en la Lista Roja de Hábitat de la Unión Europea. Caracterizaremos dos áreas, en Alentejo y Extremadura, en las que se presenta vegetación resistente a condiciones salinas, estudiando la parte superficial del suelo, las aguas del nivel freático y el clima. Los resultados iniciales sugieren la presencia de: suelos sódicos (ECe < 2 dS/m y PSI >15); vegetación halófila; agua alcalina y elevada concentración de sales y disminución de precipitación con aumento de la Evapotranspiración potencial /ETo). El deterioro ambiental como consecuencia del cambio de uso de los terrenos circundantes, así como la tendencia a la aridización ponen en peligro la singular presencia de este hábitat.

Abstract The protection of ecosystems is a guarantee of the sustainability of human activities. The presence of exceptional habitats in the southwest of the Iberian Peninsula is frequent, making their study and conservation essential. This is the case of the inland Mediterranean salt steppes, being described in small extensions of Alentejo and Extremadura. Their study, correct interpretation and conservation should be a priority, as this habitat is considered in the Red List of Habitats of the European Union. We will characterize two areas, in Alentejo and Extremadura, where vegetation resistant to saline conditions is present, studying the topsoil, water table and climate. Initial results suggest the presence of: sodic soils (ECe < 2 dS/m and PSI >15); halophilic vegetation; alkaline water with high salt concentration, and decreased precipitation with increased potential Evapotranspiration (ETo). Environmental deterioration due to land use change, as well as the trend towards aridity, threaten the unique presence of this habitat

FTIR-ATR spectra as fingerprints of forest floor composition

Abstract It’s known that soil has a great potential for C sequestration, but it is also important to point out the contribution of forest ecosystems to the mitigation of global warming. Mixed forest stands has arouse great relevance in forestry research. However, it is necessary to increase the knowledge about quantity and quality of its soil organic matter (SOM), and species mixture effect on its decomposition dinamics. Fourier transform infrared spectroscopy-attenuated total reflectance (FTIR-ATR) is a powerful analytical tool for molecular characterization of plant materials. Its use with litter samples may simplify its processing and characterization. This study analizes forest floor of mixed and pure stands of Scots pine (Pinus sylvestris) and Sessile oak (Quercus sp.) with FTIR-ATR, to see if this analysis allows us to: separate litter samples by species, decomposition state, and determine if decomposition dynamics are affected by the stand type. A principal component analysis and Linear mixed models were applied. Results showed that FTIR-ATR analysis is a useful tool in the study of litter composition. This fast and economic analysis allows to differentiate (p<0.01) between species, as well as litter humification state. Finally, results showed that litter decomposition dynamics are affected by the type of mass (p<0.01).

Resumen Los ecosistemas forestales tienen un gran potencial para la captura de C, contribuyendo de a mitigar el calentamiento global. En las últimas décadas, los bosques mixtos han despertado gran interés en la investigación forestal. Sin embargo, es necesario incrementar el conocimiento sobre la cantidad y calidad de su MOS, y el efecto de la mezcla de especies sobre la dinámica de descomposición de la hojarasca. La reflectancia total atenuada por espectroscopia infrarroja transformada de Fourier (FTIR-ATR) es una poderosa herramienta analítica para la caracterización molecular de materiales vegetales. Su uso con muestras de hojarasca puede simplificar su procesamiento. Este estudio analiza la hojarasca de rodales puros y mixtos de pino silvestre (Pinus sylvestris) y roble albar (Quercus sp.) con FTIR-ATR, para comprobar si permite: separar las muestras por especie, por estado de descomposición, y determinar si la dinámica de descomposición se ve afectada por el tipo de rodal. Los resultados mostraron que el análisis FTIR-ATR es una herramienta útil en el estudio de la composición de la hojarasca. Este rápido y económico análisis permite diferenciar (p<0,01) entre especies, así como el estado de humificación de la hojarasca. Finalmente, los resultados mostraron que la dinámica de descomposición de la hojarasca si se ve afectada por el tipo de masa (p<0.01).

How does climate change affect soil salinity? The case study of a Mediterranean pasture with saline groundwater

Abstract The case study is located in an agricultural area of alluvial origin, approximately 10 km northeast of Lisbon (Portugal). The area is a peninsula surrounded by River Tejo, its estuary, and by River Sorraia. The peninsula lies 1 to 2 m above sea level, with saline groundwater arising from the estuarine tides. The soil is typically clayey and homogeneous. The future climate projections for the Mediterranean region show a decrease in precipitation, increase in mean temperature, and increase in sea water level. These conditions aggravate the processes leading to salt-affected soils (increased evapotranspiration, decrease in salt leaching during the rainy season, and increase of the groundwater salinity). This work evaluates the influence of climate change on soil salinity and water content in a rainfed spontaneous pasture, using Hydrus-1D. Three climate scenarios, comprising series of 30 years obtained with a regional climate model, were used: reference scenario (referent to 1971-2000), RCP4.5, and RCP 8.5 (both for 2011-2040). The results show an increase in the soil salinity in the RCP scenarios compared to the reference and a decrease in the mean yearly water content of the topsoil. Both effects limit the productivity of the pasture and even compromise the plants’ growth.

Resumo O caso de estudo situa-se na Lezíria de Vila Franca de Xira, uma zona agrícola de origem aluvial, a cerca de 10 km a nordeste de Lisboa. A Lezíria é uma península rodeada pelo rio Tejo, pelo seu estuário e pelo rio Sorraia, entre 1 a 2 m acima do nível do mar, com água subterrânea salina resultante da influência marinha no estuário. As projeções climáticas para a região indicam uma diminuição da precipitação, aumento da temperatura média e aumento do nível da água do mar. Estas condições agravam os processos de salinização do solo (aumento da evapotranspiração, diminuição da lixiviação dos sais pela chuva e aumento da salinidade das águas subterrâneas). Este trabalho pretende analisar a influência das alterações climáticas na salinidade do solo e teor de água numa pastagem espontânea de sequeiro, utilizando Hydrus-1D. Foram simulados três cenários climáticos, compreendendo séries de 30 anos obtidas a partir de um modelo climático regional: cenário de referência (referente a 1971-2000), RCP4.5 e RCP 8.5 (ambos para 2011-2040). Os resultados mostram um aumento da salinidade do solo nos cenários RCP em relação à referência e uma diminuição no teor de água médio anual na camada superficial do solo. Ambos os efeitos limitam a produtividade da pastagem, podendo comprometer totalmente o crescimento das plantas.

Closure strategy with Technosols for the environmental recovery of São Domingos mining area

Resumen La existencia de minas abandonadas sin gestión ni responsabilidad ambiental, principalmente explotadas antes de los años 80, son un gran problema para las administraciones públicas, cuya prioridad estratégica es minimizar los impactos generados. Bajo este contexto, en la mina de São Domingos (Portugal), la EDM - Empresa de Desemvolvimento Mineiro (EDM) desarrolló un proyecto de recuperación ambiental con aplicación de Tecnosoles, integrando las intervenciones de rehabilitación ambiental definidas en el Plan Director para esta área. Este proyecto permitió evaluar, en un ensayo piloto de 1,5 ha en condiciones de campo, la efectividad a largo plazo (tras 12 meses) de esta tecnología en la mejora de materiales sujetos al lavado contínuo por drenaje ácido. Se implementó una cobertura de 35 cm de Tecnosol, el cual fue diseñado con las propiedades alcalinas y eutróficas en respuesta de la necesidad determinada de los materiales en estudios previos. Tras la aplicación del Tecnosol y siembra de una cobertura de herbáceas, se evaluó la mejora de la calidad físico-química de los Tecnosoles, material de una area control (sin aplicación de Tecnosol) y material subyacente al Tecnosol. También la cobertura vegetal fue evaluada a lo largo del tiempo. Los resultados mostraron que los Tecnosoles son una alternativa eficaz que permite aumentar el pH y la fertilidad, soportar una cobertura vegetal estable y densa, así como reducir en más del 80% la disponibilidad de contaminantes de los materiales contaminados permitiendo obtener zonas para futuros aprovechamientos sin riesgos para el ambiente.

Abstract The existence of abandoned mines without management or environmental responsibility, mainly exploited before the 1980s, is an important problem for public administrations, whose strategic priority is to minimize the impacts generated. In this context, in the São Domingos minining area (Portugal), the EDM - Empresa de Desemvolvimento Mineiro developed a project of environmental rehabilitation with Technosols integrating the environmental rehabilitation interventions defined in the Master Plan for this large area. This project allowed the evaluation, in pilot assay with 1.5 ha and under field conditions, the long-term effectiveness (after 12 months) of this technology. A layer with 35 cm of Technosol, which was designed with alkaline and eutrophic properties due to the needs of the materials, was applied. After the Technosol application and herbaceous sowing, the physical-chemical quality of the Technosols, material from a control area (without Technosol application) and contaminated material located below the Technosol was evaluated. The results showed that Technosols are an effective alternative that allows the increasing of the pH and fertility, support a dense and stable plant cover as well as the diminution (more than 80 %) of the availability of contaminants from the contaminated materials, allowing future land uses (agricultural, forestry, etc.) without environmental risk.

Soil erosion in mountain shrub areas: effect of prescribed fire

Resumo Atualmente, um dos maiores problemas ambientais ao nível do globo é a perda de solo por erosão hídrica. O agente erosivo pode provocar perdas significativas de nutrientes e matéria orgânica, principalmente quando a superfície do solo suporta um reduzido coberto vegetal. Em Portugal, o fogo controlado é uma prática comumente utilizada no controlo da disponibilidade de combustível e consequente redução do risco de incêndio. Contudo, esta prática remove em grande parte a cobertura vegetal, deixando o solo mais exposto aos processos erosivos. Neste sentido, o presente trabalho tem como objetivo avaliar o efeito do fogo controlado na erosão hídrica em áreas de matos do Parque Natural de Montesinho, NE Portugal. Após o fogo, foram instaladas 6 parcelas de erosão de 4 m2 cada (4 × 1 m), para avaliação da perda de solo e do escoamento superficial na área queimada. Os resultados englobam 8 meses de ensaio (março a dezembro de 2021), e as colheitas foram realizadas por cada evento de precipitação, perfazendo um total de 6 avaliações. O volume de água de escoamento e a perda de solo (massa de sedimentos) foram obtidos através de cálculos que englobaram o escoamento, os sedimentos transportados para o interior dos reservatórios de colheita do escoamento e os sedimentos depositados na parte frontal das parcelas de erosão (colocação de um dispositivo que permite a recolha dos sedimentos transportados). A quantidade média de perda de solo foi de 15,4 g m-2, o escoamento superficial médio foi de 1,4 mm, traduzindo-se num coeficiente de escoamento de 4,2%. Para avaliação das perdas de C e N, os sedimentos foram separados em 4 classes de tamanho (<0,2mm, 0,2-0,5mm, 0,5-2mm, >2mm) e analisadas em laboratórios as concentrações de C e N. A baixa precipitação total, durante o período de ensaio, ocasionou baixos valores de escoamento e, portanto, baixos valores de perda de solo, de C e de N.

Abstract Currently, one of the biggest environmental problems at the global level is the soil loss by water erosion. The erosive agent can cause significant losses of nutrients and organic matter, especially when the soil surface supports a reduced vegetation cover. In Portugal, prescribed fire is a commonly used practice to control the fuel availability and consequently reduce the wildfires risk. However, this practice removes the vegetation cover, leaving the soil more exposed to erosive processes. In this sense, the present work aims to evaluate the effect of prescribed fire on water erosion in shrub areas of the Montesinho Natural Park, NE Portugal. After the fire, 6 erosion plots of 4 m2 each (4 × 1 m) were installed to assess soil loss and runoff in the burned area. The results encompass 8 months (March to December 2021), and samples were collected for each rainfall event, making a total of 6 evaluations. The runoff and soil loss (sediment mass) were obtained through calculations that encompassed the runoff, the sediments transported into the runoff collection reservoirs and the sediments deposited on the front of the erosion plots (placement of a device that allows the collection of transported sediments). The average of soil loss was 15.4 g m-2, the average of runoff was 1.4 mm, corresponding to a runoff coefficient of 4.2%. To evaluate C and N losses, the sediments were separated into 4 size classes (<0.2mm, 0.2-0.5mm, 0.5-2mm, >2mm) and analyzed in laboratory the C and N concentrations. The low total precipitation, during the test period, caused low runoff values and, therefore, low losses of soil, C and N.

Molecular markers surrogated to water repellency in fire-affected soils

Resumen La repelencia al agua del suelo (RAS) se atribuye a la acumulación de compuestos hidrofóbicos (lípidos), pero su extracción no siempre elimina la RAS, lo que sugiere que componentes macromoleculares no extraíbles también pueden estar relacionados con una RAS. Se han estudiado suelos quemados (B) y control (UB) del Parque Nacional de Doñana (Huelva, España) bajo dos tipos de vegetación (alcornoque y brezo) y fracciones de suelo: gruesa (1-2 mm) y fina (<0.05 mm). La composición molecular de la materia orgánica del suelo (MOS) se analizó mediante espectrometría de masas de ultra-alta resolución. Además, se empleó la regresión por mínimos cuadrados parciales (PLS) para explorar la relación entre la RAS y la MOS definida por la abundancia de los 1221 compuestos orgánicos comunes. También se utilizaron índices para obtener gráficas que faciliten la identificación de biomarcadores de la RAS. En los suelos quemados, la RAS estaba significativamente relacionada (P<0.05) con compuestos aromáticos y condensados, mientras que, en los suelos control, la MOS incluía compuestos aromáticos y ligninas. En las fracciones finas, la RAS estuvo relacionada principalmente con lípidos, pero, no se encontró correlación en las fracciones gruesas. Los resultados permiten concluir que la hidrofobicidad depende de varias famílias de compuestos orgánicos. La combinación de la FT-ICR/MS con herramientas estadísticas ha facilitado la obtención de nuevos biomarcadores de RAS.

Abstract Soil water repellency (SWR) is often attributed to the accumulation of hydrophobic organic compounds, mainly lipids. Nonetheless, lipid extraction not always suppress SWR and unextractable soil constituents may be related with residual SWR. Burnt (B) and unburnt (UB) soils (Doñana National Park, Huelva) under two vegetations (cork oak and heather) and two soil fractions, coarse (1-2 mm) and fine (<0.05 mm) were studied. Soil organic matter (SOM) molecular composition was studied by ultra-high resolution mass spectrometry. Partial least squares regression (PLS) was employed to explore SWR in function the abundance of the 1221 common compounds found. An omic approach using various indices (e.g., factor loadings of PLS models, etc,) was applied to identify compounds which could be used as proxies for SWR. In the case of B soils, SWR was related (P< 0.05) to aromatic and condensed compounds, while in UB soils it relied mainly on aromatics and lignins. In the fine fractions, lipids were associated with SWR, and no correlation was found in the coarse fractions. In conclusion, hydrophobicity was related to lipids as expected, but also to lignin and aromatic components. The combination of FT-ICR/MS with graphical statistical approach was effective in finding molecular predictors of SWR.

Water and salt budgets in three permanent tree crops in Roxo’s irrigation district

Resumo O regadio é fundamental para a produção agrícola em Portugal. As previsões de alterações climáticas mostram uma tendência para verões mais quentes e secos, e precipitação com uma maior irregularidade na sua distribuição. O aumento de evapotranspiração associado à rega poderá levar a uma maior concentração de sais no solo e por consequência, a um aumento do risco de salinização e da perda de produção das culturas. Por estas razões, a monitorização e controlo da salinização do solo são fundamentais para a sustentabilidade do regadio. Este trabalho teve como objetivo avaliar o balanço de água e sais no solo de três culturas permanentes (olival, amendoal, clementinas) situadas no perímetro de rega do Roxo, em Aljustrel, nos anos de 2019 e 2020. Foram monitorizados os teores de água e a condutividade elétrica do extrato de saturação do solo a diferentes profundidades. Foi depois utilizado o modelo HYDRUS-1D para simular a dinâmica da água e sais no solo e avaliar a sustentabilidade das práticas agrícolas existentes. Os resultados demonstraram que não há um aumento da salinidade no solo nos três locais monitorizados, embora seja importante melhorar as práticas de rega para maximizar a eficiência do uso da água aplicada.

Abstract Irrigation is fundamental for agricultural production in Portugal. Climate change forecasts show a tendency towards warmer, drier summers, and a reduction in precipitation depths and frequency. The increase in evapotranspiration associated with irrigation mal practices may lead to a higher concentration of salts in the soil, and consequently to an increased salinization risk and loss of crop production. For these reasons, the monitoring and control of soil salinization are essential for the sustainability of irrigated agriculture. This study aimed to evaluate the water and salts budgets in three permanent crops (olive grove, almond, clementines) located in Roxo’s irrigation district, in Aljustrel, during the 2019 and 2020 growing seasons. The soil water content and the electrical conductivity of the soil saturation extract were monitored at different depths. The HYDRUS-1D model was then used to simulate the dynamics of water and salts in the soil profile and to evaluate the sustainability of existing agricultural practices. The results of this research showed that there is no increased risk of soil salinization in the three monitored sites, although it is important to improve irrigation practices to maximize the use efficiency of irrigation water.

Fire effects on soil quality in Quercus suber forests: a long-term assessment

Abstract Wildfires, despite being a major disturbance factor, have also an essential role in shaping the Mediterranean landscape and its ecological processes. Post-fire soil properties can change significantly, depending on fire charactheristics. However, long term fire effects on soil are still not well understood, particulary in the Mediterranean region and in cork oak forest systems. This study aimed to provide a long-term assessment of soil chemical characteristics in cork oak forests 16 years after a wildfire, at different depths, and of soil resillience to wildfire. The study was conducted in 2020 at Serra do Caldeirão (southern Portugal, Algarve), mainly in Leptosols. Soil sampling was carried out at two depths (0-5 cm and 5 cm-to maximum depth) in plots burned in 2004 (n=25) and unburned plots (n=12), which were used as control. Soil samples were chemically anallysed in the laboratory. Similar results were obtained for burned and unburned plots, for most of the parameters. The exceptions were extractable P (0-5 cm depth) and organic C (both depths), which were significantly higher in burned plots. The results show a natural recovery of soil characteristics after wildfire and, consequently, indicate a considerable soil resilience and the important role of vegetation on the dynamics of post-fire soil recovery.

Resumo Os incêndios, embora devastadores, são parte essencial na formação da paisagem mediterrânica e de alguns processos ecológicos que aí ocorrem. Dependendo das características do fogo, as propriedades do solo podem alterar-se significativamente. Os efeitos do fogo a longo prazo ainda não são bem compreendidos, principalmente na região mediterrânica e em particular em sistemas florestais de sobreiro. Este estudo teve como objetivo avaliar, a longo prazo e a diferentes profundidades, as características químicas dos solos de sobreirais 16 anos após um incêndio, bem como a sua resiliência a esta perturbação. Este estudo realizou-se na Serra do Caldeirão (Sul de Portugal, Algarve). A amostragem de solos decorreu em 2020 e realizou-se principalmente em Leptossolos e em duas profundidades (0-5cm e 5cm - máxima profundidade) em parcelas ardidas em 2004 (n=25) e não queimadas (n=12). As amostras de solos foram caracterizadas quimicamente. Para a maioria dos parâmetros (excepto P extraível e C orgânico) não se verificaram diferenças significativas entre os dois cenários. As concentrações de P extraível (apenas para a camada superficial) e C orgânico (ambas profundidades) foram significativamente maiores nas parcelas queimadas. Os resultados evidenciam a recuperação natural das características químicas dos solos após o fogo e, consequentemente, uma considerável resiliência desses solos, bem como o papel da vegetação na dinâmica de recuperação do solo.

RUSLE validation in soils with use in outdoor livestock production

Resumo Os sistemas de produção de suínos ao ar livre são considerados sistemas de produção mais amigos do ambiente e de maior bem-estar animal, relativamente aos sistemas de produção intensiva em ciclo completo confinado. No entanto, o comportamento dos suínos que continuamente fuçam o solo, bem como as características do clima Mediterrâneo, precipitação concentrada no Inverno e a topografia do terreno são factores que influenciam o impacto destes sistemas na erosão hídrica do solo. Este trabalho visou avaliar a adequação da Equação Universal Revista de Perda de Solo (RUSLE) na previsão das perdas de solo, aplicada a uma área com produção de suínos ao ar livre, por comparação com a perda de solo observada após 17 anos de ensaio. A aplicação da RUSLE evidenciou que o risco de erosão do solo variava de muito a extremamente severo em 96,2% da área, originando uma perda solo média de 502,4 t/ha.ano. A aplicação do modelo RUSLE conduziu ao cálculo de uma perda efectiva de solo de 609,7 t/ha.ano, o que se pode considerar uma boa adesão aos valores observados. Os resultados observados evidenciam ainda que em 3,4% da área houve sedimentação, não estando o modelo RUSLE habilitado a simular esta componente do processo.

Abstract Outdoor pig production is considered systems more environmentally friendly and with greater animal welfare, compared to intensive indoor production systems. The Mediterranean region offers good weather conditions for this type of production. However, the behavior of swine that continuously forages the soil, as well as the characteristics of the Mediterranean climate, with the precipitation concentrated in winter as well as the topography of the area are factors that influence the soil erosion in these systems. This work aimed to evaluate the adequacy of the Revised Universal Soil Loss Equation (RUSLE) applied to an area with outdoor pig production, compared to the observed soil loss after 17 years of testing. The application of RUSLE showed that the risk of soil erosion varied from very to extremely severe in 96% of the area, resulting in a soil loss of 502.4 t/ha.year. The RUSLE model agreed with field data which indicated an effective soil loss of 609.7 t/ha.year. Field data also showed that in 3.4% of the area there was sedimentation, a feature that is not provided by RUSLE.

The role of mosses in soil physico-chemical properties under two contrasting post-fire managements in Central Portugal

Abstract Mosses play an important role after wildfires, acting as early colonizers before the establishment of vascular vegetation, thus stabilizing, and protecting soil against erosion. However, little is known about the effect of moss development on soil recovery after wildfires. In this work, we studied effects of mosses on soil physicho-chemical properties in a burned eucalyptus plantation under two contrasting post-fire managements in Central Portugal, six years after wildfire. Post-fire managements were applied in two separate areas from the same wildfire and consisted of salvage logging vs. mulching with standard and low application rates (8 and 2.6 Mg ha-1, respectively). Six years after fire, for each area and management type (untreated, logged, mulched standard/low), we collected five soil samples at 0-2.5 depth with and without moss biocrusts (n=50). Soils were analysed for pH, electrical conductivity, oxidizable organic C, total N, available P, aggregate stability, macro-aggregate content, and wettability. The studied post-fire managements showed contrasting effects on soil properties in the medium-term. Whereas salvage logging did not negatively affect soils, the mulching at a standard rate increased soil fertility six years after the fire. The moss biocrust emerged after the wildfire preserved soil structure, thus decreasing the risk of soil erosion.

Resumen Los musgos juegan un papel importante tras los incendios forestales actuando como colonizadores tempranos, estabilizando y protegiendo así el suelo frente a la erosión. Sin embargo, se desconoce el efecto de los musgos sobre la recuperación del suelo post-incendio. En este trabajo estudiamos los efectos a medio plazo del musgo sobre las propiedades físicoquímicas del suelo en una plantación de eucalipto de la región Centro de Portugal, afectada por un incendio forestal y con diferente gestión post-fuego. Dicha gestión consistió en saca de madera vs. aplicación de mulch estándar y reducida (8 y 2.6 Mg ha-1, respectivamente). Seis años después del incendio, para cada zona y tipo de gestión (sin tratar, saca de madera, mulch estándar/reducido), se muestrearon 5 réplicas de suelo a 0-2,5 cm de profundidad con y sin musgo (n=50). Se analizó pH, conductividad eléctrica, C orgánico oxidable, N total, P disponible, estabilidad de agregados, contenido en macroagregados y repelencia al agua. Los tratamientos post-incendio estudiados mostraron efectos contrastados sobre las propiedades del suelo a medio plazo. La saca de madera no afectó negativamente al suelo, mientras que la aplicación estándar de mulch aumentó la fertilidad edáfica. Los musgos desarrollados tras el incendio preservaron la estructura del suelo, reduciendo así el riesgo de erosión.

A network for measuring soil physical parameters

Resumen El Institut Cartogràfic i Geològic de Catalunya (ICGC) actualmente tiene una red formada por 14 estaciones automáticas que miden los parámetros físicos de contenido de agua y temperatura del suelo. Estas estaciones están situadas en campos de cultivo de viña que han emigrado hacia cotas más altas para buscar condiciones climáticas más húmedas y frías (adaptación al cambio climático). Las estaciones están formadas por varios sensores ambientales (pluviometría, radiación solar, temperatura i humedad del aire) y por sensores enterrados en el suelo que miden el contenido de agua y la temperatura, situados a 5, 20, 50 y 100 cm de profundidad, y así poder contrastar los parámetros ambientales con los físicos del suelo. Son estaciones autónomas alimentadas por energía solar que, a través de un módem, transfieren los datos periódicamente a una base de datos remota situada en la sede central del ICGC. Estos datos son acesibles a través de un visor público en el cual se pueden consultar también la información edafólogica donde están situados los sensores. Los datos obtenidos de los sensores se pueden descargar en formato csv o visualizar graficamente. Estos datos se pueden visualizar gráficamente y descargar a través de un visor web de acceso público, el cual también permite consultar la información edafólogica del lugar donde está situada la estación. Los datos, además de permitir determinar los régimenes climáticos de los suelos, a medio plazo también serán útiles realizar estudios hidrológicos y de cambio climático; aunque para esto último se necesitan registro de los datos de intervalos de tiempo mayores, por lo que todavía quedará esperar ya que las primeras estaciones automáticas se instalaron en el 2017.

Abstract The Institut Cartogràfic i Geològic de Catalunya (ICGC) currently has a network of 14 automatic stations that measure the soil water content and temperature. These stations are installed in vineyards that have migrated to higher levels to search for more humid and colder climatic conditions (adaptation to climate change). Stations consist of various environmental sensors (rainfall, solar radiation, air temperature and humidity) and a set of sensors, buried into the ground at 5, 20, 50 and 100 cm depths, to measure water content and temperature, enabling to compare the environmental parameters with the physical ones of the soil. They are autonomous stations powered by solar energy that, through a modem, periodically transfer data to a remote database located at the ICGC headquarters. These data are displayed graphically and downloaded through an open web app, which also provides information about the soil where the station is located. Obtained data, in addition to compute the climatic regimes of soils, in the medium term will be useful to carry out hydrological and climate change studies; although for the latter, at least longer years of registration are needed, so it will still have to wait since because the first automatic stations were installed in 2017.

The use of Pollution-Induced Community Tolerance (PICT) to Ni to assess the effects of remediation techniques

Resumen Los tratamientos de remediación en suelos contaminados por metales pesados están muy extendidos. No obstante, generalmente, cuando se evalúa su eficacia después de la aplicación, únicamente se tienen en cuenta fracciones del metal (soluble, biodisponible, etc.). Sin embargo, también es relevante conocer el estado de los microorganismos del suelo por las funciones esenciales que desempeñan. En este trabajo se evaluó el efecto de trés tratamientos de remediación en un suelo contaminado por Ni sobre las comunidades bacterianas, en términos de desarrollo de tolerancia al Ni. Los tratamientos de remediación fueron: concha de mejillón (CMT), corteza de pino (CP) y EDTA. También se estableció un control sin tratamientos. La CMT fue el tratamiento más efectivo y menos nocivo, ya que las comunidades bacterianas no desarrollaron tolerancia en respuesta a las adiciones de Ni al suelo. La remediación con CP sólo fue efectiva para niveles de Ni de 500 y 1000 mg·kg-1, pero las comunidades bacterianas desarrollaron tolerancia al Ni para 2000 mg·kg-1. El lavado del suelo con EDTA fue efectivo en términos de desarrollo de tolerancia al Ni por las comunidades bacterianas; no obstante, este procedimiento con EDTA fue demasiado nocivo para las bacterias, perjudicando la salud de la comunidad.

Abstract The use of remediation techniques in polluted soils with heavy metals is widespread. However, in general, after remediation application, only metal fractions (soluble, bioavailable, et.) are taken into account in the assessment of their efficacy. In this sense, it is also relevant to know the status of soil microorganisms because of the essential functions they perform. In the present study, the effect of three remediation techniques on the development of bacterial community tolerance to Ni was assessed. The selected remediation techniques were: crushed mussel shell (CMS), pine bark (PB), and EDTA. A no-treatment control was also established. CMS was the most effective and least harmful treatment, as the bacterial communities did not develop tolerance in response to Ni additions to the soil. Ni-remediation with CP was only effective for Ni levels of 500 and 1000 mg·kg-1, but bacterial communities developed tolerance to Ni at 2000 mg·kg-1. Washing Ni out of the soil with EDTA was effective in terms of the development of bacterial community tolerance to Ni; however, EDTA-procedure was too harmful to the bacteria, damaging the health of the community.

Use of physical-chemical and ecotoxicological parameters in the evaluation of remediation of soils degraded by mining activities

Resumo Na remediação de solos potencialmente contaminados por atividades mineiras, é importante considerar tecnologias ambientalmente sustentáveis, aplicáveis a áreas extensas. A estratégia de remediação in situ, que recorre à adição de corretivos orgânicos, ou inorgânicos, permite a reabilitação destes solos, melhorando as suas características e imobilizando os contaminantes, colocando-os em formas menos biodisponíveis. Os corretivos adicionados ao solo podem ser, preferencialmente, resíduos, cuja valorização vai ao encontro das metas Europeias estabelecidas relativamente à deposição de resíduos em aterros. De facto, é fundamental a diminuição dessas quantidades, valorizando os resíduos, e promovendo a sua integração no sistema produtivo. Este estudo teve como objetivo avaliar o uso sustentável de materiais provenientes da indústria da pasta de papel e do papel (cinzas de biomassa e lamas biológicas) na melhoria da qualidade de solos contaminados por atividades mineiras na Faixa Piritosa Ibérica (FPI): Minas de Aljustrel, Lousal e São Domingos), em dois tempos distintos: 1 e 25 meses após a aplicação dos materiais. Foram utilizados parâmetros físico-químicos e ecotoxicológicos. Os resultados sugerem que os aditivos testados permitiram uma clara melhoria nas propriedades físico-químicas dos solos, essenciais para a recuperação das suas características e funções, e diminuição nas respostas tóxicas para vários organismos-teste, Pseudokirchneriella subcapitata, Thamnocephalus platyurus e Daphnia magna, quando expostos a extratos dos solos corrigidos.

Abstract In the remediation of soils potentially contaminated by mining activities, it is important to consider environmentally sustainable technologies, applicable to large areas. The in situ remediation strategy that consists in the addition of organic, or inorganic, amendments, allows the rehabilitation of these soils, improving soil characteristics and immobilizing contaminants, turning them into less bioavailable forms. The recovery of this type of materials meets the European goals established for the disposal of waste in landfills, considering that it is essential to reduce the quantities deposited in landfills and increase their recovery, promoting their integration into the production system. This study aimed to evaluate the sustainable use of materials from the pulp and paper industry (biomass ashes and biological sludge) in improving the quality of soils contaminated by mining activities in the Iberian Pyrite Belt (IPB: Aljustrel, Lousal and São Domingos Mines), at two different times: 1 and 25 months after application of the materials. Physicochemical and ecotoxicological parameters were used in that evaluation. The results suggested that the tested amendments allowed a clear improvement in the physicochemical properties of the soils, essential for the recovery of their characteristics and functions, and a reduction of the toxic response of several test organisms, Pseudokirchneriella subcapitata, Thamnocephalus platyurus and Daphnia magna, when exposed to the soil-water extracts of amended soils.

Impact of Temperature and Sustainable Agricultural Practices on the Degradation of Herbicides

Resumen El objetivo de este trabajo fue evaluar mediante un experimento de laboratorio el impacto del uso de paja de trigo como acolchado o como enmienda orgánica del suelo en la cinética de degradación de los herbicidas S-metolacloro (SMOC) y foramsulfuron (FORAM), y en la formación de sus metabolitos mayoritarios a dos temperaturas de incubación. Los tratamientos ensayados correspondieron a paja de trigo molida (P), dos suelos agrícolas sin enmendar (S1 y S2) y enmendados con 10% (p/p) de P (S1+P y S2+P). Las muestras tratadas con ambos herbicidas se incubaron en la oscuridad a 14ºC ó 24ºC y al 40% de su correspondiente capacidad de campo. La degradación de FORAM fue siempre más rápida que la de SMOC en los suelos sin enmendar, y viceversa en los tratamientos P, S1+P y S2+P. La aplicación de la paja al suelo aumentó la vida media (DT50) de ambos herbicidas a las dos temperaturas de incubación debido a su mayor adsorción y menor biodisponibilidd para ser degradados. La degradación de SMOC sobre la paja fue mucho más rápida que la de FORAM. Los herbicidas mostraron una degradación 1,1-3,1 veces más rápida a 24°C que a 14°C. Se observó la formación de los tres metabolitos en todos los tratamientos.

Abstract The objective of this work was to evaluate, through a laboratory experiment, the impact of the use of wheat straw as mulch or as an organic soil amendment on the degradation kinetics of the herbicides S-metolachlor (SMOC) and foramsulfuron (FORAM), and in the formation of their major metabolites at two incubation temperatures. The treatments assayed corresponded to milled wheat straw (P), two agricultural soils non-amended (S1 and S2) and amended with 10% (w/w) of P (S1+P and S2+P). The samples treated with both herbicides were incubated at 14ºC or 24ºC and 40% of their corresponding maximum field capacity in the dark. FORAM always showed a faster degradation than SMOC in the unamended soils, and viceversa in P, S1+P and S2+P treatments. The application of straw to soil increased the half-lives (DT50) for both herbicides at the two incubation temperatures due to their higher adsorption and lower bioavailability of the herbicides to be degraded. The degradation of SMOC on straw was much faster than that observed for FORAM. The herbicides showed a faster degradation at 24°C (1.1-3.1 times) than that observed at 14°C. The formation of the three metabolites was observed in all the treatments.

Effect of ketamine on edaphic fauna: behaviour and reproduction assay with Eisenia fetida

Resumo A utilização crescente de cetamina para fins terapêuticos e recreativos tem motivado preocupações ao nível ambiental. Esta substância tem sido detetada em efluentes, devido à ineficiência das técnicas aplicadas nas estações de tratamento de águas residuais. Sendo que parte destes efluentes podem ser usados como águas para reutilização em práticas agrícolas, importa perceber os efeitos que a cetamina apresenta em organismos edáficos como as minhocas, facto que constitui o objetivo deste trabalho. Várias concentrações de cetamina (0, 25, 250 e 2500 µg/kg) foram testadas e avaliados os efeitos, através de testes de fuga e reprodução, usando como modelo biológico as minhocas Eisenia fetida, tendo como endpoints o comportamento de fuga e a reprodução, de acordo com as normas da ISO e OECD. Os resultados indicaram ausência de diferenças significativas (p>0,05) entre as concentrações estudadas. Em média, a cetamina promoveu a fuga e a diminuição do número de juvenis na ordem dos 11% e 26%, respetivamente, comparativamente ao tratamento controlo. Estes resultados parecem indicar que as concentrações estudadas não promovem efeitos negativos quer no comportamento como na reprodução, pelo que importa ponderar a realização de mais estudos, nos quais sejam consideradas concentrações superiores às aplicadas no presente trabalho, de modo a definir níveis de risco em ambiente edáfico.

Abstract The increasing use of ketamine for therapeutic and recreational purposes has increased the environmental concerns. This substance has been detected in treated effluents, due to the inefficiency of treatments applied in wastewater treatment plants. Since part of these effluents can be used as water for reuse in agricultural practices, it is important to understand the effects of ketamine on edaphic organisms such as earthworms, which is the objective of the present work. Various concentrations of ketamine (0, 25, 250 and 2500 µg/kg) were tested and the effects evaluate by avoidance and reproduction tests, using Eisenia fetida as a biological model, considered the avoidance behaviour and reproduction as endpoints, according to ISO and OECD guidelines. The results indicated no significant differences (p>0.05) between the concentrations studied. On average, ketamine promoted an escape and a decrease in the number of juveniles in the order of 11% and 26%, respectively, compared to the control treatment. These results seem to indicate no negative effects of the studied concentrations on behaviour and reproduction of earthworms. More studies are needed, with higher concentrations than those applied in the present work in order to define risk levels in edaphic environment.

Recovery of gold mine tailings functional biodiversity by assisted phytoremediation

Resumen Los microorganismos juegan un papel importante en las funciones del suelo. Sin embargo, muchas veces su actividad se ve afectada por la contaminación derivada de las actividades humanas. Una de las actividades con mayor impacto sobre el medio ambiente es la minería, y más concretamente la minería a pequeña escala debido a su falta de regulación, que la convierte en un foco de contaminación como consecuencia del manejo inadecuado de los residuos. Con el fin de evaluar el efecto de la fitorremediación asistida por microorganismos y una enmienda orgánica en la diversidad funcional de dichas arenas de relave, se llevó a cabo un ensayo de fitorremediación en microcosmos en el municipio de Buriticá en Colombia, región muy afectada por minería informal. En el ensayo se utilizó una leguminosa, Enterolobium cyclocarpum en macetas con arena de relave y arena de relave enmendada, junto con distintos microorganismos (micorrizas y fijadores de nitrógeno). El ensayo se mantuvo 240 días. Los resultados del estudio demostraron que los suelos enmendados presentaron una mayor diversidad funcional que aquellos sin enmendar siendo las diferencias significativas. Dicho efecto no se vió aumentado tras la aplicación de inóculos, e incluso se observaron valores de diversidad menores. Se discuten las posibles causas e implicaciones de dichas variaciones.

Abstract Microorganisms play an important role in soil functions. However, their activity is often affected by pollution from human activities. One of the activities with the greatest impact on the environment is mining, and more specifically small-scale mining due to its lack of regulation, which makes it a source of contamination, as a consequence of inadequate waste management. In order to evaluate the effect of phytoremediation assisted by microorganisms and an organic amendment on the functional diversity of these tailings sands, a microcosm phytoremediation trial was carried out in the municipality of Buriticá in Colombia, a region highly affected by informal mining. The trial used a legume, Enterolobium cyclocarpum, in pots with mine tailings and tailings amended with compost, together with different microorganisms (mycorrhizae and nitrogen fixers). The test was maintained for 240 days. The results of the study showed that the amended soils presented a greater functional diversity than the unamended soils, and the differences were significant. This effect was not increased after inoculum application, and even lower diversity values were observed. The possible causes and implications of these variations are discussed.

Phytoremediation with Enterolobium cyclocarpum in tailing sands from informal gold mining contaminated with arsenic and cadmium

Resumen La minería informal supone un riesgo para la salud de los ecosistemas. Con el objetivo de restaurar las zonas afectadas por este tipo de actividad de una forma sostenible, se realizó un ensayo en microcosmos durante ocho meses con Enterolobium cyclocarpum, (Jacq.) Griseb. 1960, inoculadas con microorganismos promotores del crecimiento en arenas de relave procedentes de minería informal. Este estudio se hizo dentro de un invernadero ubicado en el municipio de Buriticá del departamento de Antioquia (dentro de los predios de Zijin - Continental Gold). La especie vegetal fue plantada en macetas de 10 L, conteniendo aproximadamente 14 kg de arenas de relave (A) o arenas de relave mezclada con materia orgánica [5% p/p de gallinaza compostada (A+MO)]. Se ensayó el efecto de microorganismos comerciales. En cada maceta se añadieron Micorrizas (0 g ó 50 g Mycorfos®), ó Rizobium (0 cm3 ó 0,5 cm3 de Rhizobiol® ó la mezcla de los 2 en las mismas dosis. En total hubo 24 macetas. A pesar de los altos niveles de elementos traza (ET) totales en las arenas de relave (As 269 mg/kg; Cd 461 mg/kg), el Enterolobium cyclocarpum se adaptó a las condiciones de los sustratos, presentando en el tratamiento de arena con micorrizas, la mayor concentración de As y Cd acumulado en las partes aéreas de las plantas. Por su parte, en los tratamientos sin enmienda orgánica que llevaban incorporados hongos micorrícicos, A+M y A+FN+M, la mayor concentración de As y Cd se presentó en la raíz.

Abstract Informal mining poses a risk to ecosystem health. With the aim of restoring the areas affected by this type of activity in a sustainable way, a microcosm trial was carried out for eight months with Enterolobium cyclocarpum, (Jacq.) Griseb. 1960, inoculated with growth-promoting microorganisms in tailings sands from informal mining. This study was carried out in a greenhouse located in the municipality of Buriticá in the department of Antioquia (on the premises of Zijin - Continental Gold). The plant species were planted in 10 L pots, containing approximately 14 kg of tailings sand (A) or tailings sand mixed with organic matter [5% w/w composted poultry manure (A+MO)]. The effect of commercial micro-organisms was tested. Mycorrhizae (0 g or 50 g Mycorfos®), or Rhizobium (0 cm3 or 0.5 cm3 of Rhizobiol® or a mixture of the two at the same doses were added to each pot. In total there were 24 pots. Despite the high levels of total trace elements in the tailings sand (As 269 mg/kg; Cd 461 mg/kg), Enterolobium cyclocarpum adapted to the substrate conditions, with the highest concentration of As and Cd accumulated in the aerial parts of the plants in the mycorrhizal sand treatment. On the other hand, in the treatments without organic amendment that incorporated mycorrhizal fungi, A+M and A+FN+M, the highest concentrations of As and Cd were found in the roots.

Elemental chemical characterization of soils from two ice-free sectors in southern Livingston Island (northern Antarctic Peninsula region)

Resumen Algunos ecosistemas terrestres antárticos se ven considerablemente afectados por el cambio climático, sobre todo en la región norte de la Península Antártica, que ha tenido el mayor aumento de temperatura en los últimos 60 años. Este calentamiento ha sido más pronunciado desde 2017 y ha provocado el retroceso de numerosos glaciares. Ello ha provocado la incipiente formación de suelos, que se encuentran sometidos a la acción de factores de formación (clima, biota, topografía), acción de animales (aves, mamíferos) y actividades humanas, y que evolucionan hacia una mayor producción y diversidad biológica. En este trabajo se determinó (en febrero de 2022) la composición química de los suelos en diferentes áreas de la Península Hurd y de Punta Hannah (parte meridional de la isla Livingston). En estos suelos los elementos mayoritarios (%) fueron Si, Fe, Ca, K, y Al y los minoritarios (ppm) Ti, Zr, Mn, Sr, P, y S. Estos componentes han permitido agrupar suelos según diferentes condiciones e impactos naturales, además de observar el tipo y la distribución de la vegetación como indicador del desarrollo edáfico.

Abstract Some Antarctic terrestrial ecosystems are greatly affected by climate change, especially in the northern Antarctic Peninsula region which has had the greatest temperature increase in the last 60 years. This increase has been more pronounced since 2017 and has caused a retreat of many glaciers. The retreat has caused the generation of soils, which are subjected to environmental effects (radiation, wind, temperatures), animal actions (birds, mammals) and human activities, and which evolve to greater biological production and diversity. Preliminary data on the chemical composition of soils were collected on February 2022 from different areas of Hurd Peninsula and Hannah Point (southern Livingston Island). The percentage of major elements (%) such as Si, Fe, Ca, K, and Al or minoritary (ppm) Ti, Zr, Mn, Sr, P, and S can be used to group soils according to different natural conditions and impacts. Furthermore, type and distribution of vegetation can be an indicator of soil development.

Acid Mine Drainage remediation through artificial soils with biochar

Abstract Acid mine drainage (AMD) is a serious environmental problem associated with the mine sector when minerals that contains sulfur are exposed. The effluents discharge, in water bodies, with low pH and high metals levels, can pose a threat to the ecosystems, even after the mine exploration ceases. Hence, treatments for the AMD are necessary and can be accomplish by mine restoration actions. The project Mindingsoils aims to mitigate ADM by applying artificial soils with biochar under a circular economy concept, that will promote the reduction of runoff generated, increase of the mine pH runoff and provide metals sorption capacity. To that aim, the mine residues and different biochars (Acacia, Pine and Eucalyptus) were chemically characterized. The results showed that the mine residues, with high level of metals and low pH, will promote environmental negative effects in the adjacent water bodies. From the different tested biochars, Acacia spp. was the feedstock that had more potential for ADM remediation strategies due to its high cation exchange capacity as well as H and O ratios. These results allowed the design of the artificial soil, which will be tested in a pilot field experimental.

Resumo A drenagem ácida de minas (DAM) é um problema ambiental sério associado à exploração mineira quando minerais contendo enxofre são expostos às condições atmosféricas. Os efluentes gerados com pH baixo e alto teor de metais podem representar uma ameaça para os ecossistemas, mesmo após a mina estar encerrada, e por isso, o seu tratamento é necessário podendo ser atingindo através de ações de restauro. O projeto Mindingsoils tem por objetivo o tratamento de DAM através do uso de solos artificiais com biochar, baseado no conceito de economia circular, que vai promover a redução do escoamento gerado, aumento do pH do escoamento e ao providenciar a capacidade de sorção de metais. Para tal, os resíduos de mina, assim como diferentes biochares (acacia, pinheiro e eucalipto) foram caraterizados quimicamente. Os resultados mostraram que os resíduos da mina, tendo valores elevados de metais e baixo pH, irão promover efeitos ambientais negativos nos corpos de água adjacentes. O biochar de acacia foi selecionado para o presente estudo devido à sua maior capacidade de troca catiónica e a sua proporção de H e O. Os resultados permitiram o desenho do solo artificial, que irá ser testado num ensaio piloto de campo.

Depth distribution of trace elements in urban soil profiles

Resumen Los suelos son un componente importante de los ecosistemas urbanos, pero sus funciones pueden verse afectadas negativamente por el aumento de la población urbana previsto para las próximas décadas. Entre los problemas que sufren los suelos urbanos, se destaca la acumulación de contaminantes inorgánicos. Este trabajo analiza las concentraciones de Pb, Cu, Zn, Ni y Cr en seis suelos de la ciudad de Santiago de Compostela (noroeste de España), tres de ellos desarrollados en condiciones naturales y tres formados sobre materiales transportados/alterados por actividades humanas. En dos de los suelos naturales las concentraciones de los metales traza muestran una tendencia clara a descender en profundidad, lo que sugiere que el aporte procede de la contaminación del entorno. En el otro suelo natural, formado sobre anfibolitas, esta tendencia solo se cumple para el Pb, mientras que el Cu, Ni y Cr aumentan en profundidad, lo que puede explicarse por la naturaleza del material de partida. Por el contrario, en ninguno de los tres suelos artificiales se observa una tendencia clara en la distribución de los metales en profundidad.

Abstract Soils are an important component of urban ecosystems, but their ecosystemic functions may be negatively affected by the growth in urban population projected for the next decades. Among the problems that affect urban soils, the accumulation of inorganic contaminants such as heavy metals is one of the most challenging. In this study we analized the concentrations of Pb, Cu, Zn, Ni and Cr in six soil profiles of the city of Santiago de Compostela (northwestern Spain). Three of them are developed under natural conditions, and the other three are developed over human altered and transported materials. In two of the natural soils, trace metal concentrations show a clear trend to decrease with depth, suggesting that metals come from the environmental pollution. In the other natural soil, developed from amphibiles, this trend is only true for Pb , while Cu, Zn, Ni and Cr increase in depth, which can be explained by the particular lithology of this soil. On the contrary, in none of the three artificial soils a clear trend in the distribution of trace element concentrations with depth is observed.

Adsorption of Ionizable Herbicides by Agricultural Soils without Amendment and Green Compost-Amended Soils

Resumen El objetivo de este trabajo fue estudiar la adsorción de aminopiralid e iodosulfuron-metil sodio, aplicados en post-emergencia en cultivo de trigo, y dos productos de degradación, metsulfuron-metil y 2-amino-4-metoxi-6-metil-1,3,5-triazina (AMMT), por compost vegetal (GC) y por dos suelos agrícolas (suelo A y suelo B) con diferentes caracteristicas, sin enmendar y enmendados con GC a una dosis de 2.5% p/p. El estudio de adsorción de los herbicidas y metabolitos por los suelos y GC se llevó a cabo mediante la técnica de “batch” en el equilibrio. Las concentraciones de equilibrio de los compuestos se determinaron por HPLC-MS, excepto las de 14C-iodosulfuron-metil sodio que fueron determinados en un contador de centelleo líquido. Las isotermas de adsorción se ajustaron a la ecuación de Freundlich, presentando una forma lineal para la adsorción de los herbicidas por el suelo B + GC. Los valores de Kf de aminopiralid fueron mayores que los de iodosulfuron-metil sodio, indicando una mayor adsorción de este herbicida por los suelos. La capacidad de adsorción de los herbicidas y sus metabolitos por los suelos enmendados dependió del contenido en carbono orgánico (CO) y del pH del suelo. Para todos los compuestos el porcentaje adsorbido por GC fue mayor que por los suelos.

Abstract The objective of this work was to study the adsorption of aminopyralid and iodosulfuron-methyl sodium, applied in post-emergence to wheat crops, and two degradation products, metsulfuron-methyl and 2-amino-4-methoxy- 6-methyl-1,3,5-triazine (AMMT), by green compost (GC) and by two agricultural soils (soil A and soil B) with different characteristics, without amendment and amended with GC at 2.5% w/w. The study of herbicide and metabolite adsorption by soils and GC was carried out using the batch equilibrium method. The equilibrium concentrations of the compounds were determined by HPLC-MS, except for 14C-iodosulfuron-methyl sodium, which was determined in a liquid scintillation counter. The adsorption isotherms were fitted to the Freundlich equation, presenting a linear form for the adsorption of the herbicides by the soil B + GC. The Kf values of aminopyralid were higher than those of iodosulfuron-methyl sodium, indicating a greater adsorption of this herbicide by soils. The adsorption capacity of herbicides and their metabolites by amended soils depended on the soil organic carbon (OC) content and the pH. For all the compounds, the percentage adsorbed by GC was higher than by the soils.

Antibiotic resistance genes in soils: Is their transfer to plants possible?

Resumen El suelo constituye un gran reservorio de genes de resistencia a los antibióticos (ARGs) como la tetraciclina, la estreptomicina y la ciprofloxacina. La propagación de los ARGs en los suelos se atribuye principalmente a la ganadería intensiva y a las prácticas agrícolas. En particular, la aplicación de estiércoles en el suelo es una de las vías más importantes para la entrada de ARGs en los suelos agrícolas. Mientras que la diversidad y abundancia de los ARGs del suelo se han estudiado ampliamente, poco se sabe de su posterior transmisión al microbioma de las plantas. Existe la posibilidad de que los ARGs se tranfieran de los suelos enmendados a las plantas a través de la colonización de los tejidos por bacterias endófitas (foliares y radiculares) o por la adhesión de bacterias portadoras de ARGs a las superficies de las plantas. Este trabajo tiene como objetivo principal recopilar información sobre la posible transferencia de ARGs a plantas para así poder entender la magnitud del problema, puesto que puede poner en jaque la seguridad alimentaria y, por consiguiente, la salud humana.

Abstract Soil is a major reservoir of resistance genes for antibiotics (ARGs) such as tetracycline, streptomycin and ciprofloxacin. The spread of ARGs in soils is mainly attributed to intensive livestock farming and agricultural practices. In particular, the application of manures to soil is one of the most important pathways for the entry of ARGs into agricultural soils. While the diversity and abundance of ARGs in soils have been extensively studied, little is known about their subsequent transmission to the plant microbiome. The ARGs coud be transferred from amended soils to plants through colonisation of plnat tissues by foliar or root endophytic bacteria or by attachment of ARG-bearing bacteria to plant surfaces. The main objective of this work is to gather information on the possible transfer of ARGs to plants in order to understand the magnitude of the problem, as it may jeopardise food safety and, consequently, human health.

Evaluation of glomalin content and its relationship with aggregation in urban soil

Resumen La materia orgánica tiene un papel esencial en la agregación de las partículas de suelo y por ello en el desarrollo de una estructura estable. Entre los componentes orgánicos, se ha destacado el papel en la formación de agregados de la glomalina, una glicoproteína producida por hongos micorrícicos, cuyo contenido puede verse afectado por diversos factores, entre ellos el uso del suelo. En este trabajo se analiza el contenido de glomalina en 56 suelos urbanos de Santiago de Compostela, sobre distinto sustrato litológico y vegetación (forestal, prado y horticultura), y se evalúa su relación con la estabilidad de agregados. Las concentraciones de glomalina fácilmente extraíble varían entre 0,8 y 9,6 mg g-1(valor medio 4,8 mg g-1, 8 % de la materia orgánica del suelo), sin que se observen diferencias atribuibles a la litología o uso del suelo. No se observa relación significativa de estabilidad de agregados en agua con la glomalina, pero tampoco con otras formas de C soluble ni con C total, lo que se atribuye al elevado contenido de materia orgánica de los suelos estudiados, que superan los valores umbrales por encima de los cuales la materia orgánica ya no tiene efectos apreciables en la agregación.

Abstract Organic matter plays an essential role in the aggregation of soil particles and thus in the development of a stable structure. Among the organic components, the role of glomalin, a glycoprotein produced by mycorrhizal fungi, whose content can be affected by various factors, including land use, has been highlighted in the formation of aggregates. In this work, the content of glomalin in 56 urban soils of Santiago de Compostela is analyzed, on different lithological substrates and vegetation (forestry, grassland and horticulture), and its relationship with the stability of aggregates is evaluated. Easily extractable glomalin concentrations vary between 0.8 and 9.6 mg g-1 (mean value 4.8 mg g-1, 8 % of soil organic matter), with no differences attributable to lithology or land use. No significant relationship of stability of aggregates in water is observed with glomalin, but neither with other forms of soluble C nor with total C, which is attributed to the high organic matter content of the soils studied, which exceed the threshold values above of which organic matter no longer has appreciable effects on aggregation.

Short-term evolution of physico-chemical properties of Technosols made from contaminated soils by pyritic sludge

Abstract The aim of this study was to evaluate, at short term, the physico-chemical and biological quality of residually contaminated soils after the Aznalcóllar mine spill and treated with “tailor-made Technosols”. Two Technosols with different properties (T4 and T6) were used as treatments. Both are composed of ex-situ contaminated soil and two wastes from mining (sludge rich in iron oxyhydroxides and marble sludge); and T4 by a waste from agro-industry (solid olive-mill by-product) and T6 by one from urban activity (vermicompost from gardening). After 6 months of application, samples of Technosols and treated contaminated soils were characterised (soil properties, total, soluble and available concentrations of potentially harmful elements (PHEs), and toxicity bioassay with Lactuca sativa L.) and compared with baseline conditions. Some soils in the Guadiamar Green Corridor presented a significant environmental and human health risk due to their extreme characteristics (pH<4, low fertility and multielemental contamination). After only six months, the application of Technosols on these soils has led to a significant improvement in their physico-chemical and biological properties (pH neutralisation, reduction of mobility PHEs and enrichment in organic carbon). So, in the long term, soil remediation through the Technosols is expected to be effective and proven in future studies.

Resumen Nuestro objetivo fue evaluar, a corto plazo, la calidad fisicoquímica y biológica de suelos contaminados tras el accidente de Aznalcóllar y ser tratados con "Tecnosoles a la carta". Se aplicaron dos Tecnosoles (T4 y T6); ambos compuestos por suelos contaminados ex-situ y dos residuos procedentes de la minería (lodos ricos en oxihidróxidos de hierro y lodos de mármol); y T4 también por uno agrícola (subproductos sólidos de almazara) y T6 por uno urbano (vermicompost de jardinería). Tras 6 meses, se caracterizaron los Tecnosoles y los suelos contaminados tratados (propiedades del suelo, concentraciones totales, solubles y disponibles de elementos potencialmente contaminantes (EPCs), y bioensayo de toxicidad con Lactuca sativa L.) y compararon con las condiciones de partida. Algunos suelos del Corredor Verde del Guadiamar presentaban un importante riesgo ambiental y para la salud humana debido a sus características extremas (pH<4, baja fertilidad y contaminación multielemental). La aplicación de los Tecnosoles ha mejorado significativamente sus propiedades fisicoquímicas y biológicas (neutralización del pH, reducción de la movilidad de los PHE y enriquecimiento en carbono orgánico) en tan solo 6 meses. Así pues, a largo plazo, se espera que la remediación de los suelos mediante los Tecnosoles sea eficaz y demostrada en futuros estudios.

Restoration of mine tailings with organic amendments and plant species: Impact on the physical properties of the soil

Resumen El uso de enmiendas orgánicas formuladas a partir de residuos en la restauración de suelos contaminados es una práctica habitual que permite, además de valorizar residuos, mejorar las condiciones de desarrollo vegetal y reincorporar nutrientes a los ciclos biogeoquímicos naturales. No obstante, hay pocos ensayos de campo que permitan evaluar el efecto a largo plazo de esta práctica sobre las propiedades del suelo. El objetivo de este trabajo es hacer un seguimiento de la evolución de las propiedades físicas del suelo en estériles de mina restaurados mediante la aplicación de enmiendas orgánicas en combinación con la plantación de distintas especies vegetales (fitogestión), Salix viminalis o Agrostis capillaris. Las condiciones físicas del suelo eran muy desfavorables para el creicimiento vegetal en los suelos de mina sin tratar, que presentaban texturas gruesas, elevada densidad, baja porosidad y baja capacidad de almacenamiento de agua. Las técnicas de fitogestión mejoraron la agregación, redujeron la compactación y la densidad del suelo, y aumentaron su porosidad y la capacidad de retención de agua, recuperando características similares los suelos naturales del entorno.

Abstract The use of organic residue - based amendments for the restoration of polluted soils is a common practice that allows to improving soil properties and reincorporating plant nutrients to the natural biogeochemical cycles, in addition to waste valorizating. However, there are few field trials evaluating the long-term effect of this practice on soil properties. The objective of this work is to monitor the evolution of soil physical properties in mine soils restored with organic amendments in combination with two plant species (phytomanagement), Salix viminalis or Agrostis capillaris. In the non-treated soil the physical properties were very desfavourable for plant growth, with coarse textures, high density, low porosity and low capacity of water retention. Phytomanagement techniques improved aggregation, reduced both soil compaction and density, and increased both porosity and water retention capacity, recovering characteristics similar to f the surrounding natural soils.

Remediation of a chlorpyrifos contaminated soil using novel bacterial strains and cyclodextrin: evaluation of its effectiveness by ecotoxicity studies

Abstract Chlorpyrifos (CLP) is one of the most widely used insecticides in the world. However, it is highly toxic for living organisms and persistent in the environment. Biological treatment is considered as a good option to remediate polluted environmental areas. Two bacterial strains, Bacillus megaterium CCLP1 and Bacillus safensis CCLP2 were isolated from two selected agricultural soils (R and LL), using enrichment technique in presence of CLP as only carbon and energy source. These strains were able to remove in solution up to 99.1 and 98.9% of CLP after 60 d (initial concentration: 10 mg L-1). Several treatments were performed in a soil artificially contaminated with CLP to enhance its remediation: 1. biostimulation, adding micro- and macronutrients; 2. bioaugmentation, inoculating B. megaterium CCLP1 or B. safensis CCLP2; 3. Addition of randomly methylated β-cyclodextrin (RAMEB), as bioavailability enhancement; 4. bioaugmentation + RAMEB. The best CLP biodegradation results were achieved when bioaugmentation and RAMEB were jointly applied. After biodegradation treatment, an ecotoxicological test was carried out to verify the effectiveness of the bioremediation strategy in soil. Results pointed out that bacteria individually inoculated into the soil were able to decrease the toxicity to undetectable levels.

Resumen Clorpirifos (CLP) es uno de los insecticidas más usados en el mundo. Sin embargo, es altamente tóxico para los organismos vivos y persistente en el medio ambiente. El tratamiento biológico es considerado como una buena opción para recuperar áreas contaminadas. Dos cepas bacterianas, Bacillus megaterium CCLP1 y Bacillus safensis CCLP2 fueron aisladas a partir de dos suelos agrícolas a través de cultivos de enriquecimientos en presencia de CLP como única fuente de carbono y energía. Estas cepas fueron capaces de eliminar un 99.1 y 98.9% de CLP en solución tras 60 d de ensayo (concentración inicial: 10 mg L-1). Varios tratamientos fueron aplicados en un suelo artificialmente contaminado con CLPpara su biorrecuperación: 1. bioestímulo, adicionando macro- y micronutrientes; 2. bioaumento, inoculando B. megaterium CCLP1 o B. safensis CCLP2; 3. Adición de β-ciclodextrina aleatoriamente metilada (RAMEB), como potenciador de la biodisponibilidad; 4. bioaumento + RAMEB. Los mejores resultados de biodegradación de CLP fueron obtenidos cuando bioaumento y RAMEB fueron aplicados conjuntamente. Tras el tratamiento de biodegradación, un ensayo ecotoxicológico fue realizado para verificar la efectividad de la estrategia de biorrecuperación en el suelo. Los resultados mostraron que las bacterias inoculadas individualmente en el suelo fueron capaces de reducir la toxicidad a niveles indetectables.

Effects of climate change in soil organic matter molecular structure in a Mediterranean savanna

Resumen Las sabanas mediterráneas (dehesas) son sistemas agrosilvopastoriles típicos, caracterizados por la presencia dispersa de robles (Quercus spp.) y especies arbustivas. Estos ecosistemas están sometidos a una marcada estacionalidad, propia del clima mediterráneo, lo que se refleja en la dinámica microbiana del suelo. La interacción de los factores que más afectan la dinámica microbiana (clima, vegetación y suelo), es clave para comprender los ciclos biogeoquímicos que, a su vez se espera que se reflejen en la estructura de la materia orgánica (MOS). Para evaluar el efecto del cambio climático, utilizamos pirólisis analítica (Py-GC/MS) para la caracterización molecular de la MOS en un experimento de imitación en campo (2017-2021). Entre los 117 compuestos biogénicos encontrados, las distribuciones y contenidos de ác. grasos y n-alcanos fueron más sensibles a los tratamientos climáticos. Además, se observa una degradación preferencial de compuestos derivados de holocelulosa y acumulación de compuestos derivados de la lignina, que se encuentra poco evolucionada, lo que apunta a condiciones desfavorables para la su degradación. Los resultados sugieren que la composición molecular de la MOS y la aplicación de Py-GC/MS aporta información sobre los cambios ambientales del suelo y que tienen valor como biomarcadores para el seguimiento del cambio climático en suelos mediterráneos.

Abstract Mediterranean savannahs (dehesas) are typical agro-sylvo-pastoral systems, characterized by the scattered presence of oak trees (Quercus spp) and shruby species, along with the integration of other practices. These ecosystems are subjected to a marked seasonality characteristic of the Mediterranean climate, and expected to be reflected in soil microbial dynamics. The interplay of driving factors on the microbial dynamics (climate, vegetation and soil) is key to understanding biogeochemical cycles in Mediterranean forests that, in turn are expected to be reflected in soil organic matter (SOM) structure. In this communication analytical pyrolysis (Py-GC/MS) was used for the molecular characterization of SOM in a field manipulative experiment aimed to evaluate the impact of forecasted warming and drying in a five-year experiment (2017-2021). Among all the biogenic compounds that were found (a total of 117), fatty acids and aliphatic compounds (n-alkanes) were found most responsive to climatic treatments. Also, a preferential degradation of holocellulose derived compounds and accumulation and preservation of lignin derived compounds, pointing to non-favourable lignin decomposition conditions. The results suggest that SOM molecular composition, hence the application of Py-GC/MS encompasses information on soil environmental shifts having biomarker value for monitoring climate change in Mediterranean soils.

Soil microorganisms in montado: a strategy for adaptation to climate change

Resumo O Montado é um ecossistema mediterrânico florestal com particular resiliência, rico em biodiversidade e de grande relevância para a conservação da natureza. No entanto, está exposto a ameaças por pressões ambientais agravadas pelas mudanças climáticas e pela pressão do Homem, o que está a levar ao seu declínio. Os microrganismos do solo são cruciais na manutenção de várias das funções do solo onde se inclui a regulação de azoto no solo disponível para as plantas. As bactérias dos nódulos radiculares das leguminosas (conhecidas por rizóbios) podem melhorar o rendimento destes ecossistemas agroflorestais devido ao processo de fixação biológica de azoto que é levado a cabo pela simbiose que se estabelece entre estas bactérias e as leguminosas. Em Portugal, a mortalidade generalizada registada em sobreiros e azinheiras nas últimas décadas deve-se, entre outros fatores, a infeções por Phytophthora spp. nas raízes destas árvores. É, por isso, importante desenvolverem-se meios de biocontrolo para esta doença. O presente trabalho tem por base a avaliação da dimensão e eficácia da população rizobiana existente em solos de Montado. Foram também avaliadas outras importantes atividades in vitro, das bactérias isoladas dos nódulos radiculares dos trevos, como o antagonismo à Phytophthora, a solubilização de fosfato e a capacidade de degradarem a celulose.

Abstract The Montado is a particularly resilient Mediterranean forest ecosystems, rich in biodiversity and of great importance for nature conservation, However, it is exposed to threats from environmental pressures aggravated by global climate change and human pressure, which is leading to its decline. Soil microorganisms are crucial in the maintenance of several soil functions including the regulation of soil nitrogen available to plants. The bacteria in the root nodules of legumes (known as rhizobia) can improve the performance of these agroforestry ecosystems due to the process of biological nitrogen fixation that is carried out by the symbiosis established between these bacteria and legumes. In Portugal, the widespread mortality recorded in cork and holm oaks in recent decades is due, among other factors, to infections by Phytophthora spp. in the roots of these trees. It is therefore important to develop means of biocontrol for this disease. The present work is based on the evaluation of the size and effectiveness of the rhizobial population existing in Montado soils. It was also evaluated, the in vitro antagonist activity to Phytophthora, of the bacteria isolated from root nodules, phosphate solubilization and the ability to degrade cellulose, an essential component of Phytophthora cell wall.

Control of the root lesion Pratylenchus penetrans - the effect of nematicidal activity of plant-derived compounds

Abstract The root lesion nematode, Pratylenchus penetrans, is one of the most harmful plant parasites, responsible for worldwide productivity losses in a significant number of plant hosts. Generally, chemical control relies on synthetic compounds used through fumigation or direct contact, which offers a systemic protection. These control methods are costly and hazardous to the environment and to humans. Phytochemicals may play an important role in nematode control. The nematicidal activity of eight compounds that occur naturaly in plants, from two classes of compounds, was assessed at 2 mg/mL, for 24 h. Bioassays were performed following the standard direct contact methodology. P. penetrans was remarkably tolerant to the tested compounds, with mortality range between 1.0 and 5.8 %. To the best of our knowledge, the nematicidal activity of 4 phenolic compounds (catechin, caffeic acid, gallic acid and gentisic acid) was evaluated for the first time for P. penetrans.

Resumo O nemátode das lesões radiculares, Pratylenchus penetrans, é um dos fitoparasitas mais destrutivo, responsável por perdas a nível mundial num significativo número de plantas hospedeiras. O controlo químico destes organismos baseia-se em fumigantes e não fumigantes, que providenciam uma protecção sistémica. Tais métodos de controlo são dispendiosos e prejudiciais quer para o ambiente quer para os humanos. Os compostos produzidos naturalmente pelas plantas poderão desempenhar um papel importante no controlo de nemátodes. A actividade nematicida de 8 compostos que ocorrem naturalmente em plantas, de duas classes de compostos, foi avaliada a 2 mg/mL durante 24 h. Os ensaios foram efectuados segundo a metodologia de contacto directo usualmente empregue. P. penetrans revelou-se extremamente insensível aos compostos testados com valores de mortalidade compreendidos entre 1.0 e 5.8%. No nosso conhecimento, a actividade nematicida de 4 compostos fenólicos (catequina, ácido cafeico, ácido gálico e ácido gentísico) foi testada pela primeira vez em P. penetrans.

Phytoremediation of soils affected by shooting practises: lessons learned, challenges and future opportunities

Resumen La contaminación por metal(oid)es de los suelos dentro de o cercanos a las instalaciones de tiro recreativas es un problema ambiental que se ha agravado en las últimas décadas. La caída constante de munición (compuesta esta principalmente por plomo -Pb-) a los suelos y su dispersión ha dado lugar a zonas con altas concentraciones totales de Pb, oscilando entre miles a decenas de miles de mg kg-1 de peso seco suelo según nos acercamos a la línea de tiro o bermas. Una vez depositados en el suelo, los fragmentos de la munición son muy susceptibles a los procesos de meteorización, que hacen que se libere el Pb en sus formas químicas más móviles y potencialmente tóxicas. En los últimos años la fitorremediación ha cogido fuerza como alternativa a los tratamientos fisico-químicos para el control y la gestión de la contaminación por Pb en los campos de tiro debido a su fácil aplicación, beneficios ambientales y bajo coste. En este contexto, el objetivo principal de este trabajo es revisar el estado del arte de la fitorremediación de los suelos afectados por las prácticas de tiro y, además, reflexionar sobre los retos actuales y futuros a abordar para su óptima remediación.

Abstract Metal(oid)-contamination of soils within or near recreational shooting ranges is an environmental problem that has worsened in recent decades. The constant fall of ammunition (composed mainly of lead -Pb-) into soils and its dispersal has resulted in areas with high total Pb concentrations, ranging from thousands to tens of thousands of mg kg-1 dry weight of soil as one approaches the firing line or berms. Once deposited in the soil, ammunition fragments are highly susceptible to weathering processes, which release Pb in its more mobile and potentially toxic chemical forms. Phytoremediation has gained momentum in recent years as an alternative to physico-chemical treatments for the control and management of Pb contamination in shooting ranges, due to it is environmentally friendly, easy to applicate and low cost. In this context, the main objective of this work is to review the state of the art of phytoremediation of soils affected by shooting practices and, in addition, to reflect on the current and future challenges to be addressed for their optimal remediation.

Bioremdiation of motor oil contaminated soils using biostimulants obtained from sewage sludge

Resumen El objetivo de este trabajo fue comprobar la capacidad biorremediadora de tres bioestimulantes (BS) producidos a partir de lodos de depuradora en un suelo contaminado por aceite de motor de gasolina. Dos de los bioestimulantes (BS1 y BS2) se obtuvieron por fermentación con Bacillus. licheniformis y el tercero (BS3) por hidrólisis enzimática. El aceite de motor tiene un elevado contenido en hidrocarburos aromáticos poilcíclicos (PAH) y produjo una fuerte inhibición de la actividad microbiana del suelo. La degradación de estos hidrocarburos dependió del número de anillos aromáticos y en los suelos sin enmendar fue nula para los de 5 y 6 anillos. La aplicación de los tres BS conllevó al incremento de la actividad deshidrogenasa respecto al suelo contaminado sin enmendar, así como a un aumento de la degradación de los PAHs. El efecto de estas enmiendas sobre la degradación de los PAHs no solo dependió de su naturaleza, sino también del tipo de BS aplicado, siendo el hidrolizado enzimáticos el que arrojó los mejores resultados.

Abstract The aim of this work was to evaluate the bioremediation capacity of three biostimulants (BS) produced from sewage sludge in a motor oil contaminated soil. Two of the BS (BS1 and BS2) were obtained by a fermentation process with Bacillus licheniformis and the third (BS3) by enzymatic hydrolysis. Motor oil has a high content of polycyclic aromatic hydrocarbons (PAHs) and caused a strong inhibition of the soil microbial activity. The degradation of these PAHs depended on the number of aromatic rings, being observed that hydrocarbons with 5 and 6 aromatic rings were not degraded in non-organically amended soils. The soil dehydrogenase activity as well as the degradation of PAHs increased respect to the non-amended soil when the three BS were used. The effect of these amendments not only depended on the structure of PAHs but also on the chemical composition of BS, being the better results those of the soils amended with the enzymatic hydrolysate.

Behaviour of oxifluorfen in soils amended with different sources of organic matter and subjected to severe drought

Resumen El objetivo de este trabajo fue estudiar el efecto de dos enmiendas orgáncia, estiércol de vaca (MC) y de oveja (MS), en un suelo contamiando con oxifluorfen y sometido a sequía severa. Para evaluar este efecto se dispusieron dos grupos de tratameintos, uno de los cuales se regó durante todo el periodo experimental y el otro se mantuvo seco. Los resultados mostraron que la actividad deshidrogenas era menor en los suelos secos que en los húmedos para todos los tratmientos. La presencia de oxifluorfen hizo bajar drásticamente la actividad microbiana del suelo en ambos escenarios. La adición de materia orgánica supuso el aumento de la actividad microbiana, siendo más alta para la enmienda MS que para MC. Esto podría deberse a que MS tiene más cantidad de ácidos fúlvicos que MC, más disponibles para los microorgnimos. Por otro lado, MS también tiene más ácido húmicos que juegan un papel importante en la retención de oxifluorfen, retirándolo de la solución del suelo, reduciendo su disponibilidad para la microbiota del suelo. Asimismo, se observó una mayor degradación de oxifluorfen en los suelos con MS que con MC, tanto en suelos regados como no regados.

Abstract The objective of this work was to study the effect of two organic amendments in soils contaminated with oxyfluorfen and submitted to severe drought. Two groups of treatments were arranged. One of them was watered during the experimental period and the other was maintained dry. The results obtained shown that dehydrogenase activity was lower in dry soils compared with those watered for all the treatments. Oxyfluorfen made dehydrogenase activity decrease in both scenarios. The addition of organic matter supposed an increase of this parameter, being higher in soils with MS compared with MC. This behaviour could be due to the content of fulvic acid, which were higher in MS than in MC. Fulvic acids are the more labile fraction of organic matter and, therefore, more available for microorganisms. On the other hand, MS has a bigger content of humic acid, which played a key role in the adsorption of oxyfluorfen, making the xenobiotic less available for soil microbes. Likewise, a higher degradation of oxyfluorfen was observed in soils amended with MS than those with MC, either in watered or not watered soils.

Cu and Zn in soil physical fractions of vineyards in southern Brazil

Resumo O cultivo de videiras em regiões com elevadas precipitações pluviométricas, como no sul do Brasil, envolve o uso de fungicidas para o controle das doenças fúngicas foliares. Estes fungicidas, normalmente, contêm em sua composição cobre (Cu) e zinco (Zn), promovendo o acúmulo desses metais no solo. O objetivo do trabalho foi avaliar a distribuição de Cu e Zn nas frações físicas granulométricas em solos de vinhedos do sul do Brasil. Foram coletadas amostras de solo (0-5 e 10-20 cm), em duas áreas de vinhedos e uma área de mata em três regiões do sul do Brasil, sendo uma no estado de Santa Catarina e duas no Rio Grande do Sul. As amostras da camada de 0-5 cm foram fracionadas em > 50 μm e < 50 μm. Nas amostras de solo e nas frações foram determinados os teores totais de Cu e Zn por fluorescência de raio-X. As áreas de vinhedos do sul do Brasil apresentam grandes variações nos teores totais de Cu e Zn, devido as distintas características dos solos e ao histórico de cultivo. Para o Cu não há distinção entre as frações, mas o Zn acumula, preferencialmente, na fração <50 μm.

Abstract The cultivation of vines in regions with high rainfall, as in southern Brazil, involves the use of fungicides to control foliar fungal diseases. These fungicides normally contain copper (Cu) and zinc (Zn) in their composition, promoting the accumulation of these metals in the soil. The objective of this work was to evaluate the distribution of Cu and Zn in the granulometric physical fractions in soils from vineyards in southern Brazil. Soil samples (0-5 and 10-20 cm) were collected in two areas of vineyards and a forest area in three regions of southern Brazil, one in Santa Catarina and two in Rio Grande do Sul states. Samples from the 0-5 cm layer were fractionated into > 50 μm and < 50 μm. In the soil samples and in the fractions, the total contents of Cu and Zn were determined by X-ray fluorescence. Vineyard areas in southern Brazil show great variations in total Cu and Zn contents, due to different soil characteristics and cultivation history. For Cu, there is no distinction between the fractions, but Zn accumulates, preferentially, in the fraction <50 μm.

Assisted dissipation of a mix of PAHs in contaminated soils: effect of soil type and availability enhancers

Abstract A remediation strategy using three non-toxic availability enhancers (two cyclodextrins and a rhamnolipid biosurfactant) was applied to various soils artificially contaminated with a mix of 14 Polycyclic Aromatic Hydrocarbons (PAHs) considered priority pollutants (from 3 to 6 rings). The high number of experimental factors (soil type, availability enhancers and incubation time) allowed to conduct a multivariate statistical analysis. Principal Component Analysis separated the studied PAHs in 3 groups, in relation with their molecular weight and Kow. The first principal component (PC1) was related with lower molecular weight PAHs, those with lower Kow and that have shown a high dissipation rate with final negligible contents. In this way, PC1 was related with the PAHs dissipated during the remediation process, and accordingly, the effect of incubation time was significantly associated to PC1, with decreasing values whereas time increases. Even more, this component was able to clearly separate the RAMEB (ramdomized methyl-β-cyclodextrin) from the other availability enhancers used. Otherwise, the second principal component was correlated with the higher molecular weight PAHs (5 and 6 rings) and was able to separate soils with different characteristics. The third principal component grouped two PAHs with intermediate molecular weight and more erratic dissipation pattern.

Resumen A varios suelos contaminados artificialmente con una mezcla de 14 hidrocarburos aromáticos policíclicos (PAHs) considerados contaminantes prioritarios (de 3 a 6 anillos) se les aplicó una estrategia de recuperación utilizando tres compuestos no tóxicos que aumentan su disponibilidad (dos ciclodextrinas y un biosurfactante ramnolípido). El elevado número de factores experimentales (tipo de suelo, potenciadores de la disponibilidad y tiempo de incubación), y contaminantes permitió realizar un análisis estadístico multivariante. El análisis de componentes principales separó los PAHs estudiados en 3 grupos, en relación con su peso molecular y Kow. El primer componente principal (PC1), se relacionó con los PAHs de menor peso molecular, aquellos con menor Kow y los que habían mostrado una alta tasa de disipación con muy bajos contenidos finales. De este modo, PC1 se relacionó con los PAHs disipados durante el proceso de recuperación, y, en consecuencia, el efecto del tiempo de incubación se asoció significativamente a PC1 con valores decrecientes conforme aumenta el tiempo. Además, este componente fue capaz de separar claramente la RAMEB (β-ciclodextrina aleatoriamene metilada) de los otros compuestos utilizados para aumentar la disponibilidad. Por otra parte, el segundo componente principal se correlacionó con los PAHs de mayor peso molecular (5 y 6 anillos) y fue capaz de separar suelos con características diferentes. El tercer componente principal agrupó a dos PAHs de peso molecular intermedio y con un patrón de disipación más errático.

Nematodes as soil status bioindicators: MaisSolo project

Abstract The intensive horticultural production systems in Ribatejo (central Portugal) are mostly based in monoculture with a high degree of technical intervention. In the project MaisSolo, a consortium comprising growers, farmers’ associations, researchers and academia, we aimed to demonstrate that the introduction of cover crops will help to improve soil structure and soil water properties (water infiltration and retention), enhance nutrient recycling and reduce agrochemical needs, with impact on pests and diseases cycle break. Nematodes inhabit all type of soils and are often used as soil status bioindicators. In this work, the evaluation of nematode communities was used to assess the effects on soil status of the proposed alternative practices: 1) biodiverse mixture of grasses and legumes 2) annual ryegrass and 3) biofumigation (forage turnip). In the control plot no cover crop was set. At the end of the 4-year experimental period, the number of free-living nematodes increased in all treatments compared with the control plot, namely the bacteriophagous group, in the mixture treatment, indicating an improvement in the organic matter content of each plot.

Resumo Os sistemas de produção intensivos hortoindustrais do Ribatejo (centro de Portugal) baseiam-se no recurso à monocultura e num elevado grau de intervenções culturais. O projeto MaisSolo, um consórcio formado por agricultores, associações de produtores, investigadores e a academia, teve por objetivo demonstrar que a introdução de culturas de cobertura contribui para a melhoria da estrutura do solo e da sua capacidade de retenção da água, melhorando a reciclagem de nutrientes e reduzindo a necessidade de agroquímicos, com impacto positivo na diminuição da prevalência de pragas e doenças. Os nemátodes, pequenos animais que habitam em todos os tipos de solo, são cada vez mais usados como bioindicadores do status do solo. Neste projeto, efetuou-se a avaliação das comunidades de nemátodes presentes em solos sujeitos a diferentes tratamentos: 1) consociação de leguminosas e gramíneas; 2) azevém anual e 3) biofumigação. Na parcela de controlo não se instalou qualquer cultura de cobertura. No final do período experimental (4 anos: 2017-2021), as populações de nemátodes de vida livre no solo aumentaram em todos os tratamentos comparativamente às parcelas de controlo, nomeadamente dos nemátodes bacteriófagos, o que indica uma melhoria do teor de matérias orgânica em cada um dos talhões, sobretudo naqueles com instalação de consociação.

Spatial distribution of polluting metals from mining

Resumen Las actividades extractivas de recursos metálicos generan gran cantidad de residuos que se acumulan en escombreras sólidas en las proximidades de la explotación. En este trabajo se ha estudiado la contaminación generada tras el abandono de la mina San Rafael, uno de los más de 60 yacimientos que fueron explotados en el entorno de Azuaga (Badajoz). Se estudiaron 320 ha alrededor de la mina, recogiéndose 40 muestras de lodo y suelo a 30 cm de profundidad, tanto en los alrededores del pozo (foco principal de contaminación) como en la escombrera y zonas más alejadas. El contenido total de elementos tóxicos presentes se determinó mediante ICP-MS tras digestión ácida (HNO3 y HCl). El estudio geoestadístico mediante krigeado marcó los niveles de contaminación existentes en toda la zona estudiada, deduciéndose que el entorno minero se encuentra altamente contaminado por elementos como Zn, Pb y Tl, al superar las concentraciones de los Niveles de Referencia Genéricos (NGR) establecidos para la salud de los ecosistemas (DOE, 2015; CCME, 2006). A la vista de estos resultados se aconseja acometer diferentes actuaciones que conduzcan a la minimización de dicha contaminación a fin de evitar la transferencia a la cadena trófica.

Abstract The extractive activities of metal resources generate a large amount of waste that accumulates in solid dumps in the vicinity of the operation. In this work, the contamination generated after the abandonment of the San Rafael mine, one of the more than 60 deposits that were exploited in the area of Azuaga (Badajoz), has been studied. 320 ha around the mine were studied, collecting 40 mud and soil samples at a depth of 30 cm, both in the surroundings of the well (main source of contamination) and in the dump and more distant areas. The total content of toxic elements present was determined by ICP-MS after acid digestion (HNO3 and HCl). The geostatistical study using kriging marked the existing contamination levels throughout the studied area, deducing that the mining environment is highly contaminated by elements such as Zn, Pb and Tl, exceeding the concentrations of the Generic Reference Levels (NGR) established for ecosystem health (DOE, 2015; CCME, 2006). In view of these results, it is advisable to undertake different actions that lead to the minimization of said contamination in order to avoid transfer to the food chain.

Lavandula stoechas L. as phytoremediation species

Resumen Una de las problemáticas medioambientales actuales es el incremento de la concentración de contaminantes en el medio ambiente. Las actividades mineras pueden generar contaminantes que se acumulan en el suelo. Este problema desemboca en un deterioro de los ecosistemas en los que aparece una gran acumulación de metaloides, afectando gravemente tanto a los seres vivos como al biotopo. Algunas especies de plantas han conseguido desarrollar tolerancia a estos contaminantes, absorbiéndolos o estabilizándolos, siendo capaces de mejorar la calidad del ecosistema. Algunas especies vegetales pueden ser utilizadas como método efectivo y seguro para recuperar zonas vulnerables o susceptibles de acumulación de elementos potencialmente tóxicos. El presente estudio aborda la posible utilización de Lavandula stoechas L. como planta fitoextractora para reducir la contaminación de elementos potencialmente tóxicos. Se ha evaluado la capacidad de fitoextracción para dos elementos (Pb y Zn) en una zona minera abandonada en el SW de la Península Ibérica, llamada mina La Sierra, donde se ha visto que la lavándula es capaz de desarrollarse en suelos donde la concentración de Zn y Pb es 506,05 y 461,41 mg/kg respectivamente. Se propone la utilización de esta especie para la minimización de metal(oid)es.

Abstract One of the current environmental problems is the increase in the concentration of pollutants in the environment. Mining activities can generate pollutants that accumulate in the soil. This problem leads to a deterioration of the ecosystems in which a large accumulation of metalloids appears, seriously affecting both living beings and the biotope. Some plant species have managed to develop tolerance to these pollutants, absorbing or stabilizing them, being able to improve the quality of the ecosystem. Some plant species can be used as an effective and safe method to recover vulnerable areas or those susceptible to the accumulation of potentially toxic elements. The present study deals with the possible use of Lavandula stoechas L. as a phytoextracting plant to reduce the contamination of potentially toxic elements. The phytoextraction capacity for two elements (Pb and Zn) has been evaluated in an abandoned mining area in the SW of the Iberian Peninsula, called La Sierra mine, where it has been seen that lavandula can develop in soils where the concentration of Zn and Pb is 506.05 and 461.41 mg/kg respectively. The use of this species is proposed for the minimization of metal(oid)s.

Multifunctional rainfed margins for a better carbon and biodiversity balance

Resumen Los márgenes multifuncionales (MMF) son franjas de vegetación espontánea o sembrada que se implantan en parcelas agrícolas desempeñando múltiples funciones. Establecerlos en cultivos herbáceos de secano es una práctica innovadora y fuente de múltiples beneficios medioambientales y agronómicos. Los márgenes sirven de refugio de fauna silvestre, favorecen la presencia de polinizadores e insectos auxiliares y representan una barrera física para la escorrentía y la deriva de productos fitosanitarios. Una vez que los márgenes son segados, los restos orgánicos se degradan por la biota del suelo, provocando una recirculación de nutrientes y el incremento de materia orgánica. En este trabajo se estudió el efecto de los MMF sobre la biodiversidad de la fauna epigea y el secuestro de carbono en el suelo. Se compararon tres tipos de márgenes: dos mezclas diferentes de semillas sembradas y la flora espontánea como márgen testigo; asimismo se midió el cultivo adyacente. Los márgenes promovieron una mayor biodiversidad de artrópodos que el propio cultivo, especialmente coleópteros. El analisis de suelo mostró pérdida de carbono en el cultivo, manejado de forma tradicional, aumentando en todos los tipos de MMF, tanto sembrados como espontáneos. Esta práctica tiene un gran potencial de implantación en cualquier tipo de cultivo extensivo.

Abstract Multifunctional margins (MFM) are strips of spontaneous or sown vegetation that are implanted in agricultural plots performing multiple functions. Their establishment in rainfed arable crops is an innovative agricultural practice and a source of multiple environmental and agronomic benefits. They serve as shelter for wildlife, favour the presence of pollinators and auxiliary insects and represent a physical barrier to runoff and drift of phytosanitary products. Once the margins are mowed, the organic residues are degraded by the soil biota, causing a recirculation of nutrients and an increase in organic matter. In this work, the effects of MFM on biodiversity of epigean fauna and the carbon sequestration in soil were studied. Three types of margins were compared: two different sown mixtures and spontaneous flora as control; likewise, the adjacent crop was tested. The margins promoted greater arthropod biodiversity than the crop, especially beetles. The soil analysis showed a loss of carbon in the crop conventionally managed, increasing in all types of MFM either sown as spontaneous ones. This practice has great potential of implementation in any type of extensive crop.

Evolution of soil salinity in Roxo’s irrigation district

Resumo Avaliou-se a evolução da salinidade do solo, em diferentes solos e culturas regadas, no perímetro de rega do Roxo. Selecionaram-se dez locais, com amendoal, olival, citrinos e romãs instalados em solos AL, LV, RG, PL e VR (WRB 2014). As culturas estudadas apresentavam tolerâncias diferentes à salinidade do solo. As campanhas de monitorização decorreram de maio de 2019 a maio de 2021. Colheram-se amostras de solo num máximo até 80 cm de profundidade, onde se determinou a condutividade elétrica do extrato de saturação do solo (ECe). A condutividade elétrica média da água de rega foi de 0,72 e de 0,66 dS/m em 2019/2020 e em 2021, respetivamente. A salinidade variou ao longo do tempo, mas sem atingir valores preocupantes para as culturas. Nas culturas sensíveis à salinidade (amendoal e citrinos), verificaram-se situações pontuais em que ECe em determinadas profundidades apresentava valores superiores ao limite de tolerância. No final dos ensaios, o solo apresentava valores de ECe muito próximos, ou mesmo inferiores, aos valores iniciais. Além da qualidade da água do Roxo indicar uma melhoria em relação a estudos anteriores, a precipitação ocorrida nos anos de 2019 a 2021 também contribuíu para a remoção de sais eventualmente acumulados.

Abstract Soil salinity was evaluated, in different soils and irrigated crops, in Roxo’s irrigation district from May 2019 to May 2021. Ten experimental sites were selected, with almond groves, olive groves, citrus and pomegranates installed on AL, LV, RG, PL and VR soils (WRB 2014). The studied cultures had different tolerances to soil salinity. Soil samples were taken at different depths, from the soil surface to a maximum depth of 80 cm, and the electrical conductivity of the soil saturation paste extract (ECe) was measured. The average electrical conductivity of irrigation water was 0.72 and 0.66 dS/m in 2019/2020 and 2021, respectively. The salinity varied over time, but without reaching values of concern. In salinity-sensitive crops (almond and citrus), there were occasional situations in which ECe presented values above the tolerance limit at certain depths. At the end of the monitoring period, the ECe values were very close or even lower than the initial ones. In addition to the quality of the Roxo water indicating an improvement compared to previous studies, the precipitation that occurred from 2019 to 2021 also contributed to the removal of salts that eventually accumulated in the rootzone of the soil profile.

Preliminary evaluation of physical characteristics of soils from Mediterranean cork oak forests: post fire long term assessment

Abstract Fire is an agent that promotes considerable changes in the physical, chemical and biological characteristics of soils and, consequently, in the landscape. Fire severity and duration, and intrinsic characteristics of the soils lead to different trajectories of soil recovery. Numerous studies focus on short term fire effects on soils but, the long-term post fire dynamics remains unclear. The present study was conducted in soils mainly Leptosols, from cork oak forests at Serra do Caldeirão (Algarve region, southern Portugal). Two severe wildfires occurred in this area, in 2004 and 2012. Undisturbed soil samples (<5 cm of depth) were collected in 2020 on plots burned in 2004, burned in 2012 and unburned (a total of 47 plots). The soil samples were analysed for the physical properties namely, bulk density, porosity, % of coarse/fine fraction and moisture. For all the studied parameters, the results showed no significant differences between burned and unburned areas, indicating considerable soil system resilience to forest fires. The study suggests the need of further analyses in order to understand the recovery processes of this forest system.

Resumo O fogo é um agente que altera as características físicas, químicas e biológicas dos solos e, consequentemente, da paisagem. A severidade e duração do fogo, assim como as características intrínsecas dos solos, conduzem a diferentes trajectórias de recuperação do solo. Numerosos estudos concentram-se nos efeitos do fogo nos solos a curto prazo, mas a dinâmica pós-fogo a longo prazo permanece incerta. O presente estudo foi realizado em solos, principalmente Leptossolos, do sobreiral da Serra do Caldeirão (Região do Algarve, Sul de Portugal). Esta área foi sujeita a dois incêndios florestais graves em 2004 e 2012. Amostras não perturbadas de solo (<5 cm de profundidade) foram colhidas em 2020 em parcelas queimadas em 2004 e 2012 e não queimadas (total de 47 parcelas). As amostras foram analisadas quanto às propriedades físicas, tais como densidade aparente, porosidade, % da fracção grosseira/fina e humidade. Os resultados obtidos para todos os parâmetros estudados não mostraram diferenças significativas entre as áreas ardidas e não ardidas, indicando considerável resiliência dos solos aos incêndios florestais. Este estudo sugere a necessidade de análises complementares para melhor compreender os processos de recuperação que intervêm neste sistema florestal.

Knowledge and sustainable management of agricultural soils in Portugal: barriers and opportunities

Resumo Atualmente existem sérios desafios que colocam pressão no recurso solo. A gestão sustentável dos solos agrícolas é indispensável para atenuar estas pressões e para aumentar a contribuição destes solos para alguns dos principais desafios da sociedade, como a adaptação e mitigação das alterações climáticas. No âmbito do EJP SOIL foi realizada uma consulta organizada a vários administradores do recurso solo para avaliar o conhecimento e gestão do solo agrícola em Portugal. Este estudo teve como objetivo identificar importantes barreiras e desafios que afetam atualmente o conhecimento do solo agrícola, mas também avaliar oportunidades para superar essas barreiras. Entre as barreiras mais importantes identificadas estão as de natureza técnica, networking, comunicação e económicas, que muito limitam o desenvolvimento e o pleno uso do conhecimento proveniente da investigação em solos. Os resultados deste estudo sugerem que a gestão sustentável do solo será beneficiada com: aumento de financiamento para investigação, estabelecimento de ensaios experimentais de longo prazo, criação de redes de conhecimento e infraestruturas nacionais ligadas às que operam a nível europeu e desenvolvimento de estratégias regionais de gestão do solo. O conjunto destas medidas contribuem para ecossistemas de solo mais saudáveis, resilientes e sustentáveis em Portugal.

Abstract There are currently serious challenges that place great pressure on soil resources. The sustainable management of agricultural land is essential to alleviate these pressures and to increase the contribution of these soils to some of the main challenges facing society, such as adaptation and mitigation of climate change. Within the scope of the EJP SOIL, an organized consultation was carried out with several administrators of the soil resource to assess the knowledge and management of agricultural soils in Portugal. This study aimed to identify important barriers and challenges currently affecting agricultural soil knowledge, but also to assess opportunities to overcome these barriers. Among the most important barriers identified are those of a technical, networking, communication, and economic nature, which greatly limit the development and full use of knowledge from soil research. The results of this study suggest that sustainable soil management will benefit from: increased funding for research, establishment of long-term experimental trials, creation of knowledge networks and national infrastructures linked to those operating at European level and development of regional strategies for soil management. All these measures contribute to healthier, resilient and sustainable soil ecosystems in Portugal.

Soil monoliths: a useful tool to raise soil awareness beyond the academic university field

Resumen El potencial didáctico de los monolitos edafológicos es bien conocido en ámbitos relacionados con la Ciencia del Suelo; sin embargo, los eventos divulgativos sobre el suelo, aunque en auge, son todavía escasos. El Área de Edafología y Química Agrícola de la Escuela Técnica Superior de Ingenierías Agrarias de Palencia (Universidad de Valladolid) ha promovido la creación de una colección de monolitos de suelos característicos de las provincias de Palencia y Valladolid. Esta iniciativa surge con fines educativos, divulgativos y de sensibilización ambiental. Actualmente cuenta con dos mononolitos listos para ser expuestos junto con información adicional detallada. Su uso más inmediato será formar parte de una exposición sobre bosques y cambio climático en el Museo de la Ciencia de Valladolid, un evento integrado dentro del Proyecto “Ciencia en acción: Bosques y emergencia climática” (FECYT). En este contexto se pretende dar visibilidad al papel crucial de los suelos para combatir el cambio climático como secuestradores de CO2 entre un público no especializado. A corto plazo los monolitos se utilizarán en talleres de divulgación dentro de “La Noche Europea de los Investigadores” o la “Semana de la Ciencia de Castilla y León”, entre otros. Esta colección se irá ampliando en los próximos años y su uso se irá diversificando.

Abstract The didactic potential of soil monoliths is well known in areas related to soil science. However, informative events on soil, although on the rise, are still scarce. The Soil Science and Agricultural Chemistry Department of the Higher Technical School of Agricultural Engineering of Palencia (University of Valladolid) has promoted the creation of a collection of monoliths of characteristic soils from the provinces of Palencia and Valladolid. This initiative arises with educational, disseminative and environmental awareness purposes. There are currently two mononoliths ready to be exhibited along with additional detailed information. Its most immediate use will be to take part in an exhibition on forests and climate change at the Science Museum of Valladolid, an event integrated within the project "Science in action: Forests and climate emergency" (FECYT). In this context, the aim is to draw attention to the crucial role of soils in tackling climate change as CO2 sequestrators among a non-specialist public. In the short term, the monoliths will be used in outreach workshops as part of the "European Researchers' Night" or the "Castilla y León Science Week", among others. This collection will be expanded in the coming years and their use will be diversified.

Terratech ERASMUS+ project tackling the objectives of the Farm to Fork Strategy

Abstract The success of the Farm to Fork strategy, aimed at the transition to the sustainability of European agriculture, will depend on the technological solutions that already exist and the ones that will be developed. These new technologies will allow the integration of several factors (e.g.: soil properties, climatic factors, intrinsic factors of the cultivars) in predictive assessments of water and nutrient needs, of the symptoms of pests and infections, and thus contribute to early, accurate and automated responses with less consumption of resources and agrochemicals. Similarly, better spatial management of land use will be possible. However, the large-scale digitization of agricultural production systems depends on the elimination of several sociological barriers, such as the digital illiteracy of many farmers and soil advisors. In this context, a consortium formed by 14 European partners, developed the TERRATECH Project, submitted to the ERASMUS+ Program, which aims to develop a master's course in Agriculture 4.0. During the first 18 months, the consortium developed the study plan and teaching materials for theoretical, field and laboratory classes. The course includes one period of student mobility in companies in the agri-food industry. The objective is to develop training that can be transferred to other universities.

Resumo O sucesso da estratégia do Prado ao Prato, que visa a transição para a sustentabilidade da agricultura europeia, irá depender das soluções tecnológicas já existentes e das que se irão desenvolver num futuro próximo. Estas tecnologias permitirão integrar diversos fatores (ex.: propriedades do solo, fatores climatéricos, fatores intrínsecos das cultivares) em avaliações preditivas das necessidades de água e nutrientes, da sintomatologia de pragas e infeções, e assim contribuir para respostas precoces, precisas e automatizadas com menor consumo de recursos e de agroquímicos. Do mesmo modo, será possível uma melhor gestão espacial do uso do solo. Contudo, a digitalização em larga escala da produção agrícola depende da eliminação de diversas barreiras sociológicas, como a iliteracia digital de muitos agricultores e técnicos de campo. Neste contexto, um consórcio formado por 14 parceiros europeus, desenvolveu o Projeto TERRATECH, submetido ao Programa ERASMUS+, que visa o desenvolvimento de um curso de mestrado em Agricultura 4.0. Durante os primeiros 18 meses, o consórcio desenvolveu o plano de estudos e os materiais didáticos para as aulas teóricas, de campo e laboratoriais. O curso inclui um período de mobilidade dos estudantes em empresas da indústria agroalimentar. O objetivo é desenvolver uma formação que possa ser transferida a outras universidades.

Overview of the knowledge about sustainable soil management practices in Europe

Abstract The awareness about the vital role of soil for nature and society has been increasing. Soil is presently a priority in European research, development, and innovation programs. In order to design effective research strategies, there is the need to identify the current knowledge level and its gaps. With that aim, this study collected systematic information from twenty three European countries about the impacts of sustainable soil management practices. Each team reported impacts of sustainable practices, based on a total of thirty predefined practices, grouped in four management groups (Soil tillage and cover, Crop and cropping system, Nutrient management and crop protection, and Water management). The impacts were related to the soil challenges defined by the European Joint Programme Soil. The results show that the knowledge is rather well spread over practices in the four management groups, both generally and regionally. There was a high variability in the level of knowledge or awareness about the practices related to the different soil challenges. The need for further knowledge on practices to decrease greenhouse gas emissions from agricultural soils could be clearly identified.

Resumo A consciência sobre o papel vital do solo para a natureza e a sociedade tem vindo a aumentar. Atualmente, o solo é um dos eixos prioritários dos programas de investigação, desenvolvimento e inovação na Europa. Para desenhar estratégias de investigação eficazes é necessário identificar o atual grau de conhecimento bem como as suas lacunas. Com esse objetivo, este estudo reuniu informação sistemática de vinte e três países europeus sobre os impactos das práticas sustentáveis de gestão do solo agrícola. As equipas de cada país identificaram o conhecimento sobre as práticas e seus impactos, partindo de um total de trinta práticas pré-definidas e agrupadas em quatro grupos (Lavoura e cobertura do solo, Culturas e sistemas culturais, Nutrição e proteção de plantas e Gestão da água). Os impactos foram relacionados com os desafios do solo definidos pelo European Joint Programme Soil. Os resultados mostram que o conhecimento está bastante difundido por práticas dos quatro grupos, quer a nível europeu quer regional. Há uma grande variabilidade no grau de conhecimento ou de disseminação das práticas relacionadas com os diferentes desafios do solo. A necessidade de maior conhecimento sobre as práticas para diminuir as emissões de gases de efeito estufa dos solos agrícolas pôde ser claramente identificada.

Extractability of trace metals in urban soils

Resumen El aumento de la urbanización y la industrialización pueden afectar negativamente a las funciones de los suelos urbanos. Entre los problemas más desafiantes se encuentra la acumulación de contaminantes derivados de las actividades humanas, como los metales pesados. No es suficiente conocer las concentraciones totales de estos contaminantes en los suelos, sino que es necesario evaluar su extractabilidad para simular qué concentración está disponible para las plantas y que podría suponer un riesgo al introducirse en la cadena alimentaria. En este trabajo se ha evaluado la biodisponibilidad de cinco metales pesados (Pb, Cu, Zn, Ni y Cr) en 55 suelos de la ciudad de Santiago de Compostela dedicados a distintos usos del suelo (vegetación herbácea, forestal y agrícola) y desarrollados sobre diferentes litologías. Los metales solubles se evaluaron con una extracción CaCl2 0,01M en la que solo el Zn aparece en forma soluble en cantidades significativas. Los metales disponibles para plantas, evaluados con una extracción en AEDT, siguieron una secuencia de concentraciones decreciente Pb > Zn > Cu > Ni > Cr. Las concentraciones de Zn y Cu más altas aparecen en suelos de uso agrícola, situados principalmente sobre gneis, lo que explica también la relación encontrada entre la concentración de Cu y este tipo de litología.

Abstract Urbanization and industrialization may have negative effects in urban soils functions. One of the most challenging problems is the accumulation of pollutants coming from the anthropogenic activities, such as heavy metals. It is not enough to analyse the total concentrations of this pollutants, but we need to evaluate their bioavailability and determine which concentration could enter to the food chain through plant uptake. In this study we analysed the bioavailability of five heavy metals (Pb, Cu, Zn, Ni and Cr) in 55 soils of Santiago de Compostela with different land uses (grassland, forest and agricultural) and different lithologies. Soluble metals were evaluated using an extraction with 0.01M CaCl2, in which only soluble Zn appears in a significant amount. Bioavailability of exchangeable metals, evaluated using an EDTA extraction, followed a decreasing trend Pb > Zn > Cu > Ni > Cr. Moreover, we found that higher concentrations of Zn and Cu correspond to agricultural soils, developed most over gneiss, which explains the significant relation between Cu concentrations and gneiss lithology.

Soil and vegetation recovery in an area affected by residual pollution after remediation measures

Abstract The present study evaluates the effectiveness of remediation treatments applied to residual polluted soils affected by the Aznalcóllar mining spill ocurred in 1998 (SW Spain). For this purpose, the influence of the treatments on the main soil properties and on the evolution of natural vegetation was studied. The results showed that amendments application improved the main soil properties and reduced soil toxicity, which led to a partial natural recovery of the vegetation cover and species richness in amended soils. Spergularia rubra and Lamarckia aurea, two of the main plant species present in the area and more strongly associated to high pollutant concentrations, showed a high bioaccumulation factor (BAF) for the main pollutants in the area (Pb and As) in shoots and, specially, in roots. Lamarckia aurea showed a remarkably high accumulation of these elements in roots, which is consistent with its distribution, strongly associated to areas where the vegetation growth is more restricted and where no other plant species are able to grow. Thus, both Spergularia rubra and Lamarckia aurea are important key species in this area, which may favour the subsequent colonization of the residual polluted soils by other less tolerant species to the pollutants present in these soils.

Resumen El presente estudio evalua la eficacia de diferentes tratamientos de remediación aplicados en suelos residualmente contaminados afectados por el vertido minero de Aznalcóllar, ocurrido en 1998 (SO de España). Se estudió la influencia de estos tratamientos sobre las principales propiedades del suelo y sobre la evolución de la vegetación. Los resultados mostraron que las enmiendas mejoraron las principales propiedades del suelo y redujeron su toxicidad, lo que condujo a una recuperación natural parcial de la cubierta vegetal y la riqueza de especies en los suelos enmendados. Spergularia rubra y Lamarckia aurea, dos de las principales especies vegetales presentes en la zona y más fuertemente asociadas a altas concentraciones de contaminantes, mostraron un elevado factor de bioacumulación (BAF) para los principales contaminantes en la zona (Pb y As) tanto en parte aérea como en raíz. Lamarckia aurea mostró una elevada acumulación de estos elementos en las raíces, lo que concuerda con su distribución, fuertemente asociada a zonas donde el crecimiento de la vegetación está más limitado. Spergularia rubra y Lamarckia aurea, por tanto, son especies clave en esta zona, ya que pueden favorecer la colonización posterior de estos suelos residualmente contaminados por parte de otras especies menos tolerantes a la contaminación.

Prediction of the bulk density of organic horizons in forest soils dominated by Quercus robur in Galicia

Resumen Este estudio busca un modelo predictivo de la densidad aparente (ρb) en horizontes orgánicos (O) de suelos de bosque de Quercus robur, la principal especie nativa caducifolia del NO de la Península Ibérica. Se toman muestras de horizontes O (OL y OF+OH; n=96) en 16 parcelas localizadas en Ordes (Galicia). Además de la ρb, en las muestras se determinan los niveles de C y N totales, el pH y los cationes básicos intercambiables (CBI). Los horizontes O son ácidos (pH en agua <5,0), con niveles medios de C orgánico >360 g kg-1 y una relación C/N que varía entre 21 y 26. La concentración de CBI sigue la secuencia Ca>Mg>>K>Na. El análisis de regresión múltiple resulta en un modelo que explica el 54% de la varianza de la ρb siendo la suma de CBI y el C orgánico total las variables predictoras. El error cuadrático medio (RMSE) fue 0,036 g cm-3 y el coeficiente de regresión (R2) entre valores observados y valores predichos fue de 0,65. Este modelo predictivo sugiere que la calidad de la materia orgánica es más determinante que la cantidad en la estimación de la ρb de los horizontes O de suelos de bosque de Q. robur.

Abstract This study searchs for a predictive model for bulk density (ρb) of organic horizons (O) of forest soils dominated by Quercus robur, the main deciduous native specie in the NW of the Iberian Peninsula. Samples of the O horizons (OL and OF+OH; n=96) of 16 stands located in Ordes (Galicia) were collected. In addition to ρb, pH, total contents of organic C and N as well as exchangeable base cations (CBI) were analysed in the samples. Organic horizons were acid (water pH <5,0), with an average organic C >360 g kg-1 and a C/N ratio in the range 21 to 26. The concentration of CBI follows the sequence Ca>Mg>>K>Na. The stepwise multiple linear regression resulted in a model that explains 54% of the ρb variance, being the sum of EBC and total organic C the predictor variables. The Root Mean Squared Error (RMSE) was 0,036 g cm-3 and the coefficient of regresión (R2) between observed and predicted values was 0.65. This predictive model suggests that organic matter quality, rather than its quantity, was more determinant in the estimation of the ρb of organic horizons of forest soils dominated by Q. robur.

Comparison of the microbiome of calcareous and gypseous soils in rainfed field plots under Mediterranean climate

Resumen El papel de los microorganismos en el mantenimiento de un suelo sano y equilibrado es primordial debido a las distintas funcionalidades que ofrecen, los cuales, a su vez, influirán directamente sobre los servicios ecosistémicos de dicho suelo. Su utilización como indicador de la salud del suelo puede ser de gran relevancia a nivel global. En los agroecosistemas, la composición y funcionalidad del microbioma, condicionadas por una cadena de variables ambientales, es un factor determinante en su capacidad productiva. Este trabajo se centra en las diferencias existentes entre el microbioma de un suelo calcáreo y uno calcáreo yipsícola dedicados ambos, al monocultivo de cebada. Para ello se evalúan factores como la diversidad, abundancia o funcionalidad de dichos microbiomas. Los resultados de este trabajo, dado las bajas ratios hongo/bacteria, señalan degradación en ambos casos. Aunque, atendiendo a la mayor diversidad del suelo calcáreo, este parece estar más sano. Por otra parte, hay más especialización, reflejada en mayores abundancias relativas de ciertos microorganismos, en el suelo yesoso. Este último presenta además mayor funcionalidad que puede estar relacionada con la adaptación de dichos microorganismos a mayores factores de estrés.

Abstract The role of microorganisms in maintaining healthy and balanced soil is essential due to the different functionalities they offer, which, in turn, will directly influence the soil ecosystem services. The use of microbiome as an indicator of soil health can be of great relevance at a global level. In agroecosystems, the composition of the microbiome together with the functionalities it offers, balanced or not, will determine the agricultural production of the soil. And all this will be influenced by a chain of interconnected variables that differ between ecosystems. This work focuses on the differences between the microbiome of a calcareous soil and a gypseous soil, both dedicated to barley monoculture. Factors such as microbiome diversity, abundance or functionality are evaluated. The results of this work, given the low fungus/bacteria ratios, indicate soil degradation in both cases. If we consider the greater diversity of the calcareous soil, this seems to be the healthiest. On the other hand, there is more specialization, reflected in greater relative abundances of certain microorganisms, in the calcareous gypsum soil. The latter also has greater functionality that may be related to the adaptation of these microorganisms to greater stress factors.

The Iberian Montado/Dehesa in face of climate change: Soil effects (bulk density and hydraulic conductivity)

Abstract A sustainable management of the soil is an imperative for all land use systems. The LIFE Montado-Adapt project proposed to implement several soil conservation and protection practices, in order to fight landscape and climate change in the Montado/Dehesa Iberian agro-silvo-pastoral system. This work showcases an evaluation of the effect of some soil protection measures, such as soil reduction/zero tillage and improvement of the pastures, in 4 pilot areas of the project, on 2 soil physical parameters: soil hydraulic conductivity (ks) and soil bulk density (BD). After 3 years, a ks decrease was observed, 22% (0.61 Log10 ks), being more accentuated in areas with livestock cattle exist, reaching to 37% (0.83 Log10 ks). Contrary to ks, BD increased in areas where livestock pasture occurs, between 12 and 4%, a consequence of livestock trampling. In areas where pastures do not occur, a decrease was observed, 3 and 4%, consequence of the no-tillage policy of soils, which promotes a better root development, accumulation of organic matter and soil aggregation. Even after 3 years, the soil conservation and protection practices seem to promote changes both ks and BD of the soils.

Resumo A gestão sustentável do solo é um imperativo para todos os sistemas de uso do território. O projeto LIFE Montado-Adapt propôs-se a implementar medidas de conservação e proteção do solo, por forma a combater a alteração da paisagem e as alterações climáticas do sistema agro-silvo-pastoril Montado/Dehesa Ibérico. Neste trabalho avaliou-se o efeito de medidas de conservação do solo, como redução/não mobilização e a melhoria das pastagens, em 4 áreas piloto do projeto, sobre 2 características físicas do solo: Condutividade hidráulica do solo (ks) e massa volúmica aparente (MVA). Ao fim de 3 anos, observou-se a diminuição de ks, na ordem dos 22% (0.61 Log10 ks), sendo mais acentuada nas áreas com gado de pastagens chegou aos 37% (0.83 Log10 ks). Ao contrário do ks, a MVA aumentou nas áreas onde ocorre gado pastagens, entre 12 e 4%, sendo possível consequência do pisoteio do gado. Nas áreas onde não ocorrem pastagens, a diminuição, na ordem dos 3 e 4%, consequência da não mobilização dos solos, promovendo um maior enraizamento vegetal, acumulação de matéria orgânica e agregação do solo. As práticas de conservação e proteção do solo parecem promover alterações, ao fim de 3 anos tanto na ks como na MVA.