Corn grain yield is dependent on nitrogen (N) availability during plant development. The aim of this work was to evaluate the effects of N application in presowing and water availability on grain yield and on yield components of corn, cultivated in no-tillage system after black oat. The experiment was carried out in Eldorado do Sul, State of Rio Grande do Sul, Brazil, in the 1998/99 growing season. Treatments consisted of two levels of water, one being adequate to the necessity of corn plant and the other with excessive water availability and seven systems of N application: 0-30-150, 150-30-0, 75-30-75, 0-30-60, 60-30-0, 30-30-30 e 0-30-0, corresponding to the quantity of N (kg ha-1) applied in presowing (immediately after oat desiccation), at sowing and at broadcasting of corn, respectively. With total N anticipation of the broadcasting to the presowing of corn, grain yield was reduced, principally with higher water availability and higher N dose. The number of kernels per ear was the yield component more associated with corn grain yield.
Zea mays; Avena strigosa; direct sowing
