MAIZE AND JACK BEANS INTERCROPPING AND SUCESSION AS ALTERNATIVE FOR NO-TILL SYSTEM

Abstract

The use of leguminous species under no-till system can increase the N content, decreasing the use of nitrogenous fertilizers. However, in ecosystems such as the Brazilian Savannah, the fast decomposition of their straw can result in a deficient soil cover, which can be avoided by intercropping them with a gramineous plant, such as maize. This study aimed to evaluate maize yield; macronutrients contents, with jack beans (Canavalia ensiformis) as green fertilizer and intercropped under no-till system; and rates of crop residues decomposition. The experimental design was split-plot randomized blocks, with four replications, and treatments evaluated per plot were: jack beans sown in October, followed by maize, in December; jack beans sown with maize, in December; maize sown in December, without jack beans, under rice straw; and maize without previous straw, under infesting plants residues dried up at the moment of planting. For split-plots, two N mineral doses were used (75 kg ha^-1 and 150 kg ha^-1), and, outside delineation, an additional treatment with single jack beans was applied. Treatments with leguminous species did not present significant effect on maize yield and macronutrients content, but there was higher efficiency index per area, with no competitive effect on maize yield. There was no difference among the N doses, allowing nitrogenous fertilizing reduction. Jack beans, as cover crop or intercropped with maize, did not affect macronutrients composition on the aerial part of leguminous species.