Nitrogen Fertilizers and Volatilization of Ammonia, Carbonic Gas Emissions and Urease Activity

Abstract

ABSTRACT The large-scale use of fertilizers is an essential process for replacement fertilization, maintenance or correction of nutrient levels in tropical environments. Nitrogen stands out among the elements that plants need in greater quantity, and for this reason, nitrogen fertilizer is the most consumed, with an emphasis on urea. The urea [(NH2)2CO] can present high losses of ammonia (NH3), besides potentiating carbonic gas (CO2) emissions, especially in high temperatures. For this purpose, the objective of this work was to: (a) evaluate three temperature conditions (25, 35, 45°C) in N losses through NH3 volatilization, CO2 gas emissions, soil urease enzyme activity; (b) and evaluate the potential of N losses in conventional urea fertilizers and associated technology (urea with N-(n-butyl)thiophosphoric triamide (NBPT), polymer-sulfur coated urea). The application of conventional urea (CU) promoted volatilization losses of 30.19 mg dm−3, followed by urea with NBPT (UNBPT) (27.35 mg dm−3) and polymer-sulfur coated urea (UPS) (5.21 mg dm−3) from the application of 100 mg dm−3 in the soil. Fertilizers with associated technology were more efficient than CU, with emphasis on UPS. The highest values for NH3 volatilization were recorded at 45°C for CU (38.97 mg dm−3), followed by UNBPT (38.14 mg dm−3) and UPS (10.41 mg dm−3). It is concluded that, in general, volatilization losses of NH3 and gaseous emissions of CO2 followed the following order for the applied sources: UPS <CU and order: 25°C < 35°C < 45°C for the temperatures.