FORMULAÇÕES DE ADUBOS NITROGENADO E POTÁSSICO APLICADOS EM DIFERENTES ÉPOCAS DE COBERTURA EM CULTIVO DE MILHO

Abstract

Corn production stands out in Brazil as the main cultivated cereal, and the supply of nutrients in balanced and enough amounts to meet the physiological needs throughout the crop cycle is one of the strategies that are being used to obtain high yields. Thus, this study aims to evaluate the growth biometric variables, production components, and corn yield in the Cerrado region (Brazilian savannah) subjected to fertilizer formulations applied at different coverage times. The experiment was carried out in a dystrophic Red Latosol field in the Itajá farm, in the Goianésia municipality, Goiás State (GO), Brazil, from 2020 to 2021. The experimental design was in randomized blocks, split-plot scheme (3 x 5), and three replicates. The plots were composed of three formulation types containing nitrogen (N) and/or potassium (K). The topdressing fertilization subplots were applied in five seasons [14, 21, 28, 35, and 42 days after emergence (DAE)], totaling 45 experimental units. Five plants were uprooted per experimental unit on the 90th day after emergence, and their height, stem diameter, leaf dry mass, stem dry mass, and root dry mass were evaluated. Number of leaves, sheet length, sheet width, leaf area, leaves dry mass, stem dry mass, root dry mass, cob dry mass, grains dry mass, number of cobs per plant, cob length and diameter, number of grains rows, number of grains per row, cob diameter and length, and grain size were evaluated in the physiological maturity phase of the grains. It is recommended that the topdressing fertilization be carried out on the 21st DAE for the biometric variables of growth, among them the plant height, in conventional cultivation conditions, as in the case of this research. There was no significant difference in the grain weight for the formulated 20-00-00 and 00-00-20 as topdressing fertilization for the corn crop, analyzing the yield variable. The 20-00-20 formulation is proposed for the BM.3073 VIP3 cultivar, since the producers use corn as dual-purpose (grain and silage purposes), presenting a high requirement for N and K nutrients; the whole plant will be extracted from the culm to the grains, being interesting to use it in the coverage at a 1:1 ratio.