Abstract

ALVARENGA, Paula et al. Effects of using raw or treated pig slurry as substitutes of the basal fertilization of maize with mineral phosphate. Rev. de Ciências Agrárias [online]. 2022, vol.45, n.4, pp.431-440.  Epub Dec 01, 2022. ISSN 0871-018X.  https://doi.org/10.19084/rca.28490.

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.

Keywords : pig slurry; organic fertilization; acidification; solid-liquid separation; phosphorous.

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