Analysis of growth and agronomic characteristics of off-season corn grown insuccession with soybean and submitted to nitrogen doses

Nitrogen (N) fertilizer management strategies for the cultivation of off-season corn grown in succession to soybean can be established by growth analysis. Therefore, the objective was to evaluate the growth and agronomic performance of corn in the off-season due to nitrogen levels in an Oxisol of the Cerrado of the state of Mato Grosso do Sul, Brazil. The experimental design used was in randomized blocks, arranged in a split-plot scheme, with six replications. The plots were formed by five nitrogen doses (0, 40, 80, 120 and 160 kg ha-1 of N), and the time of evaluation of the corn development parameters (30, 45, 60 and 75 days after emergency (DAE)) constituted the subplots. The source of N used was urea (45% N), with 30 DAE applied. The cultivar Invictus Viptera 3 of corn was cultivated in the off-season. Plant height, leaf area, number of leaves, dry mass of the plant shoot, physiological indexes of growth analysis were evaluated at 30, 40, 60 and 75 DAE. In the flowering period of corn, after the emission of the female inflorescence, were determined the indirect readings of the leaf chlorophyll, leaf N, height plant, and height of the ear insertion. At the physiological maturity of the grain was evaluated height of ear insertion, ear length, number of rows per ear, number of grains per row and ear diameter, the mass of a thousand grains, and grain yield. The 160 kg ha-1 dose of N showed better performance and higher morphophysiological indices for corn off-season in succession to the soybean crop. However, the higher grain yield of corn was obtained with the 126 kg ha-1 of N.