The objective of this study was to determine how much soil tillage and crop rotation affected grain yield of corn, soybean and wheat. The study was carried out at EMBRAPA (Rice and Beans), in Santo Antônio de Goiás, GO, Brazil, in a Red Latosol (Oxisol), under center pivot irrigation system, for six consecutive years. During the experimentation, 12 crops were cultivated. The tillage treatments were a) moldboard plough, b) harrow disc and c) no-tillage. The crop rotations were 1) corn-bean, 2) soybean-wheat, 3) soybean-wheat-soybean-bean-upland rice-bean and 4) corn-bean-corn bean-upland rice-bean. Rice, soybean and corn were sown in November/December and bean and wheat in May/June. For this study, only corn, soybean and wheat were considered. Soil tillage affected corn and wheat yields but did not affect soybean yield. Corn and wheat yields under mouldboard plough were higher than under no-tillage. The differences among no-tillage and the other tillage systems in relation to relative accumulative corn yield decreased as the cultivation period increased. Crop rotations did not affect the crop yields.
moldboard plough; harrow disc; no-tillage; agricultural system
