Alterações químicas do solo e performance da soja considerando a rotação de culturas e o uso de gesso em sistema plantio direto

Abstract

In acid soils with low fertility, crop rotation and improvement of the rooting profile are fundamental to increase the crop yield potential and the sustainability of cropping systems. We evaluated the chemical quality of the soil and the performance of soybean considering the use of crop succession, different crop rotations and application of phosphogypsum under a no-till system. A randomized complete block design was used, with four replications in a split-plot arrangement. In the plots, the following treatments were used: Wheat (W)/Soybean (S) succession, rotation I - Black Oat (BO)/Maize (M), W/S, W/S, BO/M, W/S, rotation II – Canola (CAN)/M, W/S, Barley (BAR)/S, CAN/M, W/S, and rotation III: BO + Ryegrass (RY)/M, BO + RY/S, BO + RY/S, Vetch (VET)/M, W/S. In the subplots, two treatments were used, with and without application of phosphogypsum, before the last soybean crop. Phosphogypsum application increased P and SO4-S contents as well as reduced the toxic effect of Al3+ in the soil, and improved the P, Ca, S, and Zn nutrition of soybean. The greater diversification of species in the rotation III provided an increase in Ca2+, K+

, SO4-S and organic carbon contents in the soil. Increases in soybean grain yield occurred with the adoption of crop succession when compared to rotation II, revealing a soybean yield potential similar to rotation III. The results suggest that greater diversification of the production system and the application of phosphogypsum promote improvements in soil quality and soybean performance.