Sidedressing nitrogen alternative sources and rates on out-of-season corn after soybean

Abstract

Out-of-season corn yield can be increased by nitrogen sidedressing fertilization even when sowed after soybean harvest. However, there is result inconsistency especially as to nitrogen sources and rates for corn in the cropping system. In order to evaluate the effect of sources and rates of sidedressed nitrogen application on out-of-season corn grown after soybean crop, an experiment was carried out on an Acrustox, in Chapadão do Céu (GO). A randomized complete block design, in 4x4 factorial scheme, and four replications was used. Treatments included four sources (urea, ammonium sulfate, urea extruded with starch (Amiréia^® 180S), and ammonium sulfonitrate with nitrification inhibitor (Entec^® 26)) and four rates of nitrogen (0; 30; 60 and 120 kg ha^-1). The source x rates interaction was not significant for any of the variables evaluated. Sidedressing nitrogen application as entec promoted higher leaf nitrogen concentration than ammonium sulfate and amiréia. Corn grain yield was higher when fertilized with sidedressing nitrogen as ammonium sulfate than amiréia. Sidedressing nitrogen increased leaf nitrogen and sulfur concentrations, plant height, stem diameter, number of ear per plant, number of grains per ear, weight of 1,000 grains, and grain yield of out-of-season corn grown after soybean crop, regardless of the source used.