NBPT (urease inhibitor) in the dynamics of ammonia volatilization

Abstract

The duality in nitrogen fertilization is central to environmental impacts and productivity. Therefore, technologies like NBPT gain prominence, as it acts to inhibit the urease by slowing it down and decreasing the volatilization of the ammonia. Thus, the objective was to reduce the doses of the agricultural additive Uremax NBPT 500® (Uremax) and to evaluate the urease activity in the dynamics of nitrogen volatilization. It has been hypothesized that increasing doses of Uremax do not alter NH3 losses but affect the dynamics of the process. For this, Red Latosol cultivated with Brachiaria decunbens was collected and under this was put nitrogen: urea; Urea with 20, 15 and 10% of Uremax; Two controls (nitrogenated from the market containing NBPT) and the control. Ammonia losses were quantified for 11 days, forming the split plot of the factorial in a completely randomized design with four replicates. For the final volatilization the treatments corresponded to the nitrogenous ones, with the same design and number of repetitions. The volatilization of the ammonia from the conventional urea is high, starting on the second day (2,765 mg) and the use of the inhibitor reduced the volatilization peak in up to four days. Doses of 10 to 20% of Uremax resulted in the same reduc­tion of daily volatilization as commercial products. Urea with Uremax decreased the volatilization by approximately 75% after 11 days. Even with particularities over time, doses of Uremax from 10% applied in conventional urea also reduced the volatilization of ammonia, remaining stable in 6 mg.