Phosphorus desorbability in soils with andic properties from the Azores, Portugal

Desorção de fósforo em solos com propriedades ândicas do Arquipélago dos Açores (Portugal)

E. Auxtero¹ & M. Madeira

 

ABSTRACT

Desorbability of phosphorus (P des) at P sorption maxima in eighteen horizons (surface and subsurface) of soils with andic properties from the Azores, Portugal, was determined by eight successive extractions using distilled water (H2O), calcium chloride (CaCl2), Bray 2 (B2), Mehlich 3 (M3), Egnér-Riehm (ER) and Olsen (OL) methods.

The highest proportions of P des by the B2, M3, ER and OL methods (29-100%) were obtained in soils with weak andic properties (Vitrandic Haplustepts, Typic Haplustepts and Andic Haplustepts), indicating that P can be easily lost from these soils to nearby water bodies, through surface runoff and subsurface drainage. In contrast, low proportions of P des (4-57%) by these methods were obtained in allophanerich (Acrudoxic Hydrudands and Typic Placudands) and non-allophanic soils (Acrudoxic Hydrudands and Alic Hapludands), indicating that large amounts of P can be sorbed in an unavailable form by these soils. Of the six methods used, the proportions of P des obtained by H2O and CaCl2 were consistently lower than those obtained by the B2, M3, ER and OL methods. The proportion of P des obtained by the B2 method was highly correlated with other methods (M3, ER and OL) suggesting that the B2 is also an effective method to extract P in most of the studied soils. The proportions of P des obtained by different methods were negatively correlated with Feo and Fed, correlatios being stronger than with Alo, Ald, Alp and Fep contents. This indicates that Feo and Fed plays an important role in desorbability of P in studied soils.

 

RESUMO

A proporção de P desorvido no solo (P des) após oito extracções sucessivas com água destilada (H2O), cloreto do cálcio (CaCl2) e pelos métodos Bray 2 (B2), Mehlich 3 (M3), Egnér-Riehm (ER) e Olsen (OL) foi determinada em dezoito horizontes (superficiais e subsuperficiais) de pedónes representativos de Andossolos dos Açores, enriquecidos com P no seu máximo desorção. As proporções de P des por estes extractantes foram comparadas e correlacionadas com os constituintes coloidais do solo. Observou-se uma grande variação da proporção de Pdes para qualquer dos extractantes, consoante a constituição coloidal do solo. As proporções de P des obtidas pela H2O e CaCl2 foram bastante menores do que as observadas para os outros extractantes, em qualquer dos horizontes dos solos estudados. Os Vitrandic Haplustepts, Typic e Andic Haplustepts, que apresentam reduzido teor de alofana e em que as propriedades ândicas estão fracamente expressas, mostraram elevada proporção de Pdes (29-100%) pelos métodos de B2, M3, ER e OL. Os fosfatos aplicados como fertilizantes neste tipo de solos ficarão facilmente disponíveis para as plantas, mas, provavelmente, serão facilmente perdidos por drenagem e erosão do solo. Assim, a aplicação de fertilizante de fósforo nesses solos deverá ser a estritamente necessária e em quantidades limitadas, de modo a minimizar as perdas de P e naturalmente a eutroficação dos cursos de água e lagoas das proximidades. Pelo contrário, tanto os horizontes superficiais como sub-superficiais dos outros pédones (Typic Placudands, Acrudoxic Hydrudands, Acrudoxic Hapludands e Alic Hapludands) mostraram uma baixa proporção de P des, sugerindo uma forte retenção e indisponibilidade do P quando aplicado a estes solos. Nestas circunstâncias, será preferível a aplicação de grandes quantidades de fertilizante de libertação lenta e contínua de P. Dos seis métodos estudados, as proporções de P des usando H2O e CaCl2 foram inferiores às obtidas com B2, M3, ER e OL. O P des obtido com B2, M3, ER e OL mostrou uma forte correlação entre eles. B2 revelou-se o extractante mais eficaz na remoção de P na maioria dos solos em estudo. As proporções de P des observadas para os extractantes mostraram uma correlação negativa com os teores de Ald, Alo, Alp, Feo, Fed, and Fep e com os valores de Alo + ½ Feo, e de retenção de P. Contudo, a correlação entre as proporções de Pdes obtidas com CaCl2, B2, M3, ER e OL com componentes ferruginosos (Feo, Fed) foi mais forte do que com componentes de Al (Alo, Ald).

 

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REFERENCES

Auxtero, E., Madeira, M. & Sousa, E. 2005. Extractable P as determined by different tests and P adsorption capacity of selected Andisols from the Azores. Rev. Ciências Agrárias, 28 (2): 119-132.        [ Links ]

Auxtero, E., Madeira, M. & Sousa, E. 2007. P adsorption and desorption capacities of selected Andisols from the Azores, Portugal. Rev. Ciências Agrárias, 30 (2): 55-66.        [ Links ]

Auxtero, E., Madeira, M. & Sousa, E. 2008. Phosphorus sorption maxima and desorbability in selected soils with andic properties from the Azores, Portugal. Geoderma, 144: 535–544.

Blakemore, L. C., Searle, P. L. & Daly, B. K. 1987. Soil Bureau Laboratory Methods: A Methods for Chemical Analysis of Soils. New Zealand: Soil Bureau Scientific Report 80.

Bray, R.H. & Kurtz, L.I. 1945. Determination of total organic and available forms of phosphorus in soils. Soil Sci., 59: 39-45.

Buurman, P., Rodeja, E.G., Martínez, A.C. & van Doesburg, J.D.J. 2004. Stratification of parent material in European volcanic and related soils studied by laser-diffraction grain-sizing and chemical analysis. Catena, 56: 127-144.

De Leenheer, L. & Van Hove, J. 1958. Determination de la teneur en carbone organique des sols. Études critiques des metodes tritrimétriques. Pédologie, 8:39-77.

Krull, E.S., Skjemstad, J.O. & Baldock, J.A. 2005. Functions of soil organic matter and the effect on soil properties. Residue Management, Soil Organic Carbon and Crop Performance. Grains Research and Development Corporation Project no. CSO 00029, 129p.

Madeira, M., Pinheiro, J. Monteiro, F., Fonseca, M. & Medina, J. 2002. Características e classificação dos Solos da Ilha do Faial (Arquipélago dos Açores). Rev. de Ciências Agrárias, 25 (3/4): 53-66.        [ Links ]

Madeira, M., Pinheiro, P., Madruga, J. & Monteiro, F. 2007. Soils of volcanic systems in Portugal. In F. Bartoli, P. Buurman, O. Arnalds, G. Stoops & E. Garcia-Rodeja (editors) Soils of Volcanic Regions of Europe, pp. 69-81 Springer Verlag, Berlin.

McDowell, R.W. & Sharpley, A.N. 2001. Approximating phosphorus release from soils to surface runoff and subsurface drainage. J. Environ. Qual., 30: 508-520.

Mehlich, A. 1984. Notes on Mehlich 3 soil test extractant: a modification of Mehlich 2 extractant. Commun. Soil Sci. Plant Anal., 15: 1409-1416.

Mehra, B. P. & Jackson, H. L. 1960. Iron oxide removal from soils and clays by a dithionite-citrate system buffered with sodium bicarbonate. Clays and Clay Min., 7: 317-327.

Murphy, J. & Riley, J. P. 1962. Modified single solution method for the determination of phosphate in natural waters. Analytica Chimica Acta, 27: 31-36.

Olsen, S.R., Cole, C.V., Watanabe. F.S. & Dean, L.A. 1954. Estimation of available phosphorus in soils by extraction with sodium bicarbonate. In Blakemore, L.C., Searle, P.L., Daly, B.K. (eds) Soil Bureau Laboratory Methods: a Method for Chemical Analysis of Soils, pp. 35-36. New Zealand Soil Bureau Scientific Report 80.

Parfitt, R.L. 1986. Towards Understanding Soil Mineralogy. Part III. Notes on Allophanes. New Zealand: Soil Bureau Laboratory Report 10A.

Pinheiro, J., Madeira, M. Monteiro, F., Medina, J., 2001. Características e classificação dos Andossolos da Ilha do Pico (Arquipélago dos Açores). Rev. de Ciências Agrárias, 24 (3/4), 48-60.        [ Links ]

Pote, D.H., Daniel, T.C., Sharpley, A.N., Moore, P.A., Edwards, D.R. & Nichols, D.J. 1996. Relating extractable soil phosphorus to phosphorus losses in run-off. J. Env. Qual., 60: 855-859.

Riehm, H. 1958. Die ammoniumlaktatessignäure. Methods zur bestimmung der leichtloslichen phosphorsäure in karbonataligen böden. Agrochimica, 3: 49-65.

Self-Davis, M.L., Moore, P.A. & Joern, B.C. 2000. Determination of water and/or dilute salt-extractable P. In Pierzynski, G.M. (ed) Methods of Phosphorus Analysis for Soils, Sediments, Residuals and Waters. Southern cooperative series bull. no. 396, pp. 24-26. USDA-CSREES Regional Committee, USA.

Sharpley, A.N., Ahuja, L.N. & Menzel, R.G. 1981. The release of soil phosphorus to runoff in relation to the kinetics of desorption. J. Env. Qual., 10: 386-391.

Sharpley, A.N., Foy, B. & Withers, P. 2000. Practical and innovative measures for the control of agricultural phosphorus losses to water. An overview. J. Env. Qual., 29:1-10.

Shoji, S., Nanzyo, M. & Dahlgren, R. 1993. Productivity and Utilization of Volcanic Ash Soils. Volcanic Ash Soils. Genesis, Properties and Utilization. Elsevier Science Publishers, The Netherlands.

Sims, J.T., Maguire, A.B., Leytem, K.L. Gartley, K.L. & Pautler, M.C., 2002. Evaluation of Mehlich 3 as an agri- environmental soil phosphorus test for the Mid-Atlantic United States of America. Soil Sci. Soc. Am. J., 66: 2016-2032.

SSS (Soil Survey Staff). 1999. Soil Taxonomy. A Basic System of Soil Classification for Making and Interpreting Soil Survey (2nd edition). Agriculture Handbook Number 436. USDA and NRCS, Washington.

Statsoft. 2004. A division of Statsoft Iberica, Inc. Lisbon, Portugal.

Turner, B.L. & Haygarth, P.M. 2000. Phosphorus forms and concentrations in leachate under four grassland soil types. Soil Sci. Soc. Am J., 64: 1090-1099.

Van der Zee, S.E.A.T.M. & van Riemsdijk, W.H., 1986. Sorption kinetics and transport of phosphate in sandy soil. Geoderma, 38: 293-359.

Villapando R.R. & Graetz D.A. 2001. Phosphorus sorption and desorption properties of the spodic horizon from selected Florida Spodosols. Soil Sci. Soc. Am. J., 65: 331-339.

 

¹ Instituto Superior de Agronomia, Universidade Técnica de Lisboa, Departamento de Ciências do Ambiente, Tapada da Ajuda, 1349-017 Lisboa, e-mail: eauxtero@iol.pt