CROP RESIDUES OF WINTER SPECIES AND THE C ORN YIELD IN THE MINIMUM TILLAGE SYSTEM

The use of legume species as a soil cover decreases soil losses by ero sion and adds N by symbiotic fixation, With the objective of determini ng the N supply capacity to corn of six winter soil cover crops specie s (Vicia sativa, Lathyrus sativus, Lupinus albus, Pisum sativum, Avena strigosa and Brassica napus) under minimum tillage, an experiment was carried out on a brunizem soil (Molisol). Two control treatments in w inter fallow without and with 110 kg/ha of N were used. The experiment al design was a completely randomized block with four repetitions for each treatment. Lupinus albus gave a yield of corn similar to that obt ained in the treatment with mineral N (5.18 and 5.42 t/ha), respective ly, and 61% higher than the winter fallow with N (3.22 t/ha). A signif icant relation between winter cover crops total N absorption and corn grain yield was observed, showing that in this experiment the N supply to corn is one of the major benefits of winter cover crops.