Uptake and exportation of micronutrients in high productivity corn fields

High yield corn has an increased demand for micronutrients, which requires updating knowledge of the nutritional demand patterns of the crop, especially under high production conditions. The objective of the currentstudy was therefore to determine the absorption and export patterns of copper (Cu), manganese (Mn), zinc (Zn) and iron (Fe) for high yield corn crops. Fifteen corn fields with high productive potential were sampled in the Alto Paranaiba, region, Minas Gerais, in the agricultural year 2014-2015. The following variables were evaluated: productivity, plant population, rows of grain per ear, grain per row, grain per ear, mass of one thousand grains, vegetation dry mass, dry mass of grains and total dry mass of the plant, besides the accumulation of micronutrients in the vegetative part and grains, and total micronutrient accumulation per whole plant. The grain and Cu, Mn, Zn and Fe harvest indices were also calculated. The data were submitted to descriptive statistics, Pearson coefficient linear correlation was calculated at the to 5% level and submitted to regression analysis. Cu and Zn absorption and export increase linearly with increased productivity. Micronutrient accumulation in high productivity maize is, in decreasing order, in the vegetative part: Fe> Mn> Zn> Cu; while in the grains and in the whole plant: Fe> Zn> Mn> Cu. Zn is the micronutrient with the highest harvest index.