Volatilização de amônia da ureia tratada com inibidores da urease associados a polímero orgânico

Abstract

The fertilizer industry has major challenges in improving its products, seeking to increase the efficiency of nutrient supply to crops, especially nitrogen sources. The addition of NBPT to urea, an additive for inhibition of the urease activity in soil, is one of the technology options available for reduction of the ammonia (N-NH3) losses. However, there are few studies for evaluation of the efficiency of the urea treated with NBPT, coated with polymers and micronutrients, that is, the association of two technologies in the same granule of the fertilizer. The aim of this work was to evaluate coating technologies to urea associated to urease inhibitors in maize crop. Two experiments were carried out: the experiment "1" in the city of Luminárias - MG and the experiment "2" in Ingaí - MG. Treatments applied in both sites were: 1) pearled urea; 2) urea + NBPT; 3) urea + organic polymer; 4) urea + organic polymer + Zn + B; 5) urea + NBPT + organic polymer; 6) urea + organic polymer + Zn (50% ZnO + 50% ZnSO 4) + B; 7) Control, without nitrogen (N), topdressed with 4 repetitions. Fertilizers were topdressed-applied in the rates of 50; 100 and 150 kg ha-1 of N. As a variable response, the losses of N-NH3 through volatilization were quantified. The results showed that, for the experiment performed in Ingaí, urea + organic polymer + Zn (50% ZnO + 50% ZnSO4) + B presented less loss by volatilization of N-NH3, whereas in Luminárias urea + organic polymer + Zn + B presented lower losses of N-NH3 by volatilization than the other treatments. Thus, the use of coating with organic polymer associated to Zn and B, regardless of the source, was efficient in reducing the losses of N-NH3 by volatilization in both sites studied.