Appropriate use of N fertilizer for irrigated corn increases the yield and the economic return, and it also reduces the risk of water pollution. The objective of this study was to determine corn response to nitrogen. The field experiment was carried out on a clayey typic Haplustox, using a complete split-plot randomized block design with four replications. Nitrogen rates (0, 60, 120, 180 and 240 kg ha-1 N as urea, in dress application split through the season) were the main plots and the rotation cropping systems, corn-corn-corn and corn-soybean-corn, were the split-plots. Nitrogen fertilization increases the corn yield in 28% in relation to control. Greatest grain yield, 11,203 kg ha-1, was obtained with the highest N rate (240 kg ha-1). There was no effect of cropping system in grain yield, but N content in shoot dry matter and in corn grains were larger in corn-soybean-corn system.
Zea mays; nitrogen; irrigation; corn-soybean rotation
