GROWTH AND PRODUCTIVITY OF CORN CULTURE GRAINS UNDER NITROGEN DOSES

Abstract

Nitrogen fertilization is one of the main factors responsible for the increase in the growth and agricultural productivity of corn, because this element is the most extracted by the crop, however, it has to be managed correctly, as it is also the one that most costs costs of production. Therefore, the objective of this research was to evaluate the growth and grain yield of the corn crop under nitrogen doses, in the region of Rio Largo, Alagoas. The experiment was carried out from 19/11/2017 to 16/03/2018. The statistical design was randomized blocks in the split plot scheme, with 20 treatments and four replications, with five levels of drip irrigation (40, 80, 120, 160 and 200% of the crop evapotranspiration - ETc) and four doses of nitrogen fertilization. (0, 75, 150 and 225 kg ha^-1 of nitrogen). The interaction between the irrigation depths and the nitrogen doses was not significant, a justification for this is that the soil with moisture above the field capacity caused a large part of the nitrogen to have been leached, thus, only the effects were analyzed. of the treatments of fertilization levels, without consequences. The total values of rainfall, ETo and ETc during the cultivation cycle were 367, 536 and 460 mm, respectively. The highest values of canopy height (240.2 cm), leaf area index (4.4) and agricultural productivity (9.0 t ha^-1) were obtained with the dose of 225 kg ha^-1 of nitrogen.