Volatilization of nitrogen sources and doses applied in covering in corn crops

Nitrogen fertilization is extremely important in corn cultivation and, applied at the correct dose and time, can reduce costs and increase productivity. Therefore, research to determine efficient doses and sources becomes important, which will enable savings in fertilization and reduction of N losses. The major bias in this issue lies in the significant loss of this nutrient, which occurs in different ways, but in a considerable, due to volatilization. Therefore, the objective of this work was to evaluate losses due to volatilization of nitrogen sources and doses in corn crops and thus determine the best way to reduce losses. The experimental design used was randomized blocks, in a 3x5 factorial scheme, with treatments consisting of a combination of three nitrogen sources [conventional urea, urea protected with a urease inhibitor and conventional urea + micronutrients (copper 0.15%) and (boron 0 .4%)] and five doses of nitrogen (0, 65, 130, 195, 260 kg ha-1), with four replications, totaling 60 experimental units. The volatilization of sources and doses was evaluated using static semi-open collectors. Conventional urea was the source that presented the lowest losses due to volatilization in all evaluations carried out. There was a tendency for N volatilization to increase with the increase in the applied dose. Studies regarding corn productivity must be carried out in order to define more accurately the best dose to be applied and whether it should be applied in a protected manner or not.