Formas de aplicação de fósforo sob calagem incorporada e superficial: efeito na acidez, disponibilidade de nutrientes e resposta de culturas

Abstract

Soybean (Glycine max) is grown in a large part of Brazil's arable land, predominantly under no-tillage system (SPD), where the application of fertilizers and limestone to the soil surface has increased. This management and fertilization and correction of the soil acidity can lead to a reduction of the productive potential of the soybean. The objective of this work was to evaluate the productive behavior and the root system of the soybean when cultivated under different modes of application of phosphorus (P) and limestone, as well as to evaluate the alteration of soil chemical attributes caused by the treatments. In this work the application of P incorporated to the soil in the sowing line on the surface and without P under the condition of surface liming and incorporated into the soil was carried out. The following parameters were evaluated: soybean yield, oat and wheat dry matter, nutrient concentration (N, Ca, Mg, P) in the soybean tissue, distribution and length of the root system, and changes in chemical attributes (P, K , Ca, Mg, pH, potential acidity) in the soil profile. The incorporation of limestone provided better soil acidity correction in subsurface, as well as a better distribution of Ca and Mg in the soil profile, providing higher soybean yield. The application of P incorporated into the soil and in the sowing line, with limestone incorporation, provided the highest yield of soybean, as well as higher levels of P and Mg in the soybean tissue. There was a stimulus to root growth of soybean in soil regions with higher P content. P and limestone contribute positively to soybean growth, especially when located in regions close to the root. Key word