EFEITO RESPONSIVO DA CULTURA DO MILHO PELA APLICAÇÃO DE COMPOSTOS MINERAIS

Abstract

The use of mineral compounds in agriculture has emerged as a promising strategy to increase crop productivity and sustainability. Many mineral compounds, although not considered fertilizers, stimulate natural processes by providing essential nutrients that participate in various physiological and growth processes, and even improve water use efficiency, tolerance to abiotic stresses, and crop quality. This thesis aimed to evaluate the effects of silicon and zinc fertilization on growth, development, and yield of corn (Zea mays L., grown in Cerrado Red Latosol). Two experiments were carried out in open-air pots using a randomized block design with five doses (0, 25, 50, 100, and 200 kg/ha⁻¹) of potassium silicate and zinc sulfate, respectively, and four replicates. The variables evaluated included morphological, physiological, and productive parameters namely, plant height, stem diameter, number of leaves, leaf length, leaf width, leaf area, leaf mass, stem mass, SPAD index, NDVI index, chlorophyll a, chlorophyll b, total chlorophyll and chlorophyll a/b. The productive components evaluated were straw mass, ear mass, cob mass, ear length, ear diameter, cob diameter, number of rows of grains in the ear, number of grains per row and the mass of 50 grains. In the first experiment, the silicon aplication provided significant increases in plant height, stem diameter, leaf area, chlorophyll content (SPAD and NDVI indices), mass of vegetative organs and ear components, with emphasis on the maximum productivity of 5582.44 kg ha⁻¹ at the dose of 118.31%. The response was predominantly quadratic, indicating an optimum application point for most variables. In the second experiment, zinc also positively influenced the variables studied, especially at intermediate doses. The best results occurred between 100% and 140% of the standard dose, with maximum productivity of 4946.30 kg ha⁻¹ at the dose of 135.56%. Both mineral compounds demonstrated potential to improve the agronomic performance of corn, with silicon being more effective in structural attributes and zinc being more associated with enzymatic metabolism and leaf pigmentation. The data reinforces the importance of rational nutritional management and the need to define adequate application ranges to maximize positive effects and avoid losses due to excess.