Nitrogen nutrition in maize fertilized with urease inhibitor-treated urea

Abstract

The aim of this study was to evaluate the influence of urea doses in coverage treated with NBPT on the production components and on the grain yield maize crop, in commercial field conditions. The experiment was carried out in Mauá da Serra, PR, in the season 2007/2008, in dystrophic Red Latosol, cultivated for 30 years under no-tillage system. The experimental design was randomized blocks with five replications and six treatments. The treatments were different doses of N (0; 40; 80; 120; 160 and 200 kg ha-1 of N). The diameter of the cob and the protein content increased linearly with increasing doses of N. The height of the cob, height of the plant, length of the cob and grain yield presented quadratic response, with the maximum value obtained in the following doses: 145; 142; 125 and 146 kg ha-1 of N, respectively. The forms of N measured originated higher levels in the leaves sampled as entire, independent of the tissue and the time sampled. The leaf tissue that best represented the nutritional status of the maize was the F6 leaf and, the readings performed on the scanner showed good negative correlation with the N-total content of the leaf.