Forms of urea and nitrogen levels in top dressing in the agronomic performance of wheat genotypes

Abstract

The objective of this study was to evaluate the effect of nitrogen fertilization in top dressing from various forms of urea in wheat genotypes on no-till system. Wheat genotypes developed by EMBRAPA (cultivars BRS 208 and BRS Pardela and line IWT 04008) were evaluated in three independents experiments in Ponta Grossa, State of Paraná, Brazil in 2008. Three forms of urea were evaluated (conventional urea, urea with urease inhibitor and protected urea) with four levels of N (0, 40, 80 and 120 kg ha-1) applied in top dressing in early tillering. Randomized block design, in a 3 x 4 factorial experiment, with four replications were used. The increase in the levels of nitrogen in any form of urea used, increase the dry mass of the flag leaf, the number of spikes m-2 and yield, but reduces hectoliter mass. The form of urea applied in top dressing does not influence the agronomic characteristics of the evaluated genotypes. Cultivars BRS 208 and BRS Pardela were more productive and had higher N content grain than line IWT 04008.