Produtividade da soja e atributos químicos e físicos do solo em plantio direto após cultivos de outono-inverno

Abstract

The succession off-season maize-soybean predominate in grain production in the Midwest region, and crop productivity is related to the soil cover levels. This study aimed to evaluate the productivity of soybean cultivars BRS 284 and BRS 360 RR in succession to autumn-winter crops. The study was conducted in the experimental area of Embrapa Agropecuaria Oeste, in Dourados, MS, in 2014/15 and 2015/16. The experimental design was a randomized block with split plot design with four replications. The main plots were the years, the subplots the four autumn-winter crops constituted by Brachiaria ruziziensis, corn intercropping with B. ruziziensis, winter maize and cowpea, and subsubplots were constituted by two soybean cultivars BRS 284 and BRS 360 RR. At flowering plant height of soybeans was evaluated, dry weight of leaves and stems. At harvest evaluated the weight of 100 grains and grain yield. Data were submitted to analysis of variance and the means compared by Tukey test at 5% probability. In 2015/16 soybean showed higher weight of 100 grains, higher plant height and higher grain yield in relation to the harvest 2014/15, when there was water restriction. The BRS 360 RR showed higher grain yield (3218 kg ha-1) in relation to BRS 284. The higher productivity of soybeans in 2014/15 (1,882 and 1,880 kg ha-1) was in succession to winter maize and B. ruziziensis, while 2015/16 there was no significant difference of crops. In years with drought stress, the benefit of the autumn-winter crops on soybean yield is more relevant.