Author(s): CARVALHO, M. C. S.; FERREIRA, A. C. B.; SANTOS, F. C.

Summary: This study aimed at evaluating the agronomic efficiency of nitrogen (N) fertilizers blended with urease inhibitor, nitrification inhibitor, and a slow-release polymer applied at different times in a no-till cotton crop as well as the possibility of reducing the number of broadcast applications using conventional and alternative N sources. The experiment was carried out in a complete randomized block design with four replications, in a (6x4)+1 factorial arrangement: six N sources (ammonium nitrate; urea; 50% urea + 50% ammonium sulfate; urea + urease inhibitor - NBPT; urea + slow-release polymer; and ammonium sulfonitrate + nitrification inhibitor - dimetil pirazol phosphate), four times of broadcast application (100% right after emergence; 50% right after emergence + 50% in phase B1 - first floral bud; 100% in phase B1; and 50% in phase B1 + 50% in phase F1 - first flower), and one control. None of the alternative N sources tested resulted in yields higher than the conventional sources (urea, ammonium nitrate, and ammonium sulfate). The highest yield was achieved when the N was applied earlier and split into two applications (50% right after emergence + 50% in phase B1). Single N application was more efficient only when using urea + slow-release polymer.

Publication year: 2010

Types of publication: Paper in annals and proceedings

Unit: Embrapa Rice & Beans

Keywords: Algodão, Fertilizante, Nitrogênio, Urease