VEGETATIVE DEVELOPMENT OF CORN PLANTS IN AMAZON BIOME SUBJECTED TO RATES, SOURCES AND TIMES OF NITROGEN APPLICATION

Abstract

The aims of study was to evaluate the effects of rates, sources and timing of nitrogen application top dressing on development of transgenic corn cultivated in Amazon Biome. The experiments were conducted in Parauapebas city, State of Pará, Brazil, in two agricultural seasons (2016/2017 and 2017/2018). The experimental design was randomized blocks, in a 5x2x2 factorial scheme, consisting of five rates of N (0; 45; 90; 135; and 180 kg ha^-1), two nitrogen sources (urea and ammonium sulfate) and two application times of N (phenological stages V₄ and V₈), with four replications. The factor N rates promoted adjustment of linear equation (leaf area index) and quadratic equation (dry mass of the leaf index). Based on the results obtained in the two agricultural harvests of corn cultivated under the conditions of the Amazon Biome, the application of N at the V₄ phenological stage at doses of 121 to 131.39 kg ha^-1 of N presented the best results for vegetative growth.