Plantas de cobertura e calagem na implantação do sistema plantio direto

Abstract

The objective of this work was to evaluate the effect of cover crops and liming on soybean yield and on soil chemical characteristics of soil profile, after the implementation of no-tillage system. The experiment was carried out in the field, during two years, in a Typical hapludox. The area was explored as pasture for five years. Three cropping systems were evaluated: soybean/fallow/soybean, soybean/Pennisetum glaucum/soybean, and soybean/Urochloa ruziziensis/soybean, with lime application at doses 0, 0.5, 1.0 and 2.0 times the amount required to raise the saturation base (V) to 50% at the 0-20 cm layer. Lime was incorporated into the soil at 20-cm depth before crop system implementation. At 490 days after liming, soil samples were taken from the depths 0-10, 10-20, 20-40, and 40-60 cm. Plant nutritional status, changes in soil chemical characteristics, and soybean yield were evaluated. Cover crops associated with liming improve soil acidity parameters - mainly when the applied dose is equal to or higher than the one recommended for V 50% -, and increase P foliar contents and soybean yield, regardless of lime. The higher the limestone rate, the greater is the move of the alkaline front in soil and the greater is the grain yield.