Effects of nitrogen application and water availability on grain yield of corn cultivated after black oat

Abstract

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.