Alternative Diversified Cropping Systems for Soybean-Maize off-Season Double-Cropping in Southern Brazil

Continuous use of the traditional soybean-maize off-season double cropping system in warm areas of southern Brazil has a negative effect on agricultural land owing to reduced straw cover on the soil, soil compaction under no-tillage and weed infestation. The aim of the work was to evaluate crop yield and profitability of alternative cropping systems to the soybean-maize off-season in southern Brazil. The experimental design consisted of randomized blocks with four replications, and involved eight cropping systems with various levels of diversification and intensification. Considering all three cultivation cycles, the average soybean yield was 12% higher in soybean-maize off-season intercropped with ruzigrass in comparison with the traditional soybean-maize off-season system. Moreover, compared with the traditional system, the yield of off-season maize increased by 4.4 and 8.2%, respectively, following the introduction of wheat or oat as a third crop between maize harvesting and soybean sowing. The profitabilities of soybean-maize off-season intercropped with ruzigrass and soybean-maize off-season with a third crop of oat or wheat were, respectively, 11.3, 10.2 and 6.6% higher than that of the traditional system. Under the conditions of the study, we identified three diversified crop rotation systems that present agronomic and economic advantages over the soybean-maize off-season double cropping system: soybean-maize off-season intercropped with ruzigrass; soybean-maize off-season with wheat as a third crop; and soybean-maize off-season with oats as a third crop.