EFFECTS OF CROP SUCCESSION AND SYSTEMS OF SOIL PREPARATION ON YIELD OF UPLAND RICE

The objective of this work was to study the effect of different crop s uccessions (S-1: rice-common bean; S-2: soybean-wheat-soybean-common b ean-rice-common bean; S-3: rice associated with Calopogonium muconoide s-common bean; and S-4: corn-common bean-corn-common bean-rice-common bean) and systems of soil preparation (P-1: moldboard plough/harrow di sc; P-2: moldboard plough; P-3: harrow disc and P-4: no-tillage) on gr ain yield and on component yield of upland rice (Oryza saliva L.). The work was conducted at Embrapa-Centro Nacional de Pesquisa de Arroz e Feij (a) over tilde o (CNPAF), Goi (a) over cap nia, Goias, Brazil, in a Dark Red Latosol, for three consecutive years. A complete randomize d design was used. Rice was cultivated annually in sucessions S-1 and S-3 and every three years in S-2 and S-4 in the months of November and December. There was a reduction in grain yield of rice during the thr ee successives cultivation, and Calopogonium muconoides was prejudicia l for yield of rice crop. Higher yield of rice was obtained when it wa s cultivated in succession every three years. Leaf area index and nutr ients absorption were lower in successions where rice was cultivated a nnually. The highest grain yield was obtained under no-tillage treatme nt.