Volatilização da uréia aplicada em cobertura na pastagem

Abstract

Nitrogen fertilization is difficult to handle, because nitrogen fertilizers have a high cost and problems of efficiency in their use by plants, which are due to some sources (MENEZES, 2004). The objective of this study was to evaluate the quantification of volatilized ammonia from urea applied as a top dressing in the pasture through the static free semi-open chamber (SALE). The experiment was installed in a native area of Brachiaria brizantha located within the UFMT/Campus Araguaia in Barra do Garças/MT. The experimental design used was randomized blocks with six doses of N: 0, 60, 120, 180, 240 and 300 kg ha-1 of N from urea. The SALE collector consisted of a transparent plastic bottle (PET) with a capacity of 2 L and an area of 0.008 m2, inside the bottle contained a 70 mL plastic pot containing sulfuric acid plus glycerin and a strip of polyethylene foam soaked in this solution. The foams soaked in acid were the means of capturing volatilized ammonia, they were collected every 24 hours in the first 3 days after urea application, then a collection was performed on the sixth day, one on the eighth and one more on the tenth day. Data were submitted to normality test (Shapiro-Wilk), homogeneity (Bartlett), analysis of variance, and F test. Loss of N-NH3 occurred mainly in the first six days after urea application and increased as if the dose of N ha-1 applied comes from urea.