DMPP mitigates N2O emissions from nitrogen fertilizer applied with concentrated and standard vinasse

Abstract The application of vinasse, an organic byproduct of ethanol production, can enhance greenhouse gas emissions from N fertilizers, especially nitrous oxide (N2O). The objective of this work was to test the efficiency of the nitrification inhibitor (NI) 3,4 dimethylpyrazole phosphate (DMPP) in reducing N2O emissions from urea (UR) and ammonium nitrate (AN) applied with or without standard (V) or concentrated vinasse (CV). Two laboratory studies were conducted with repacked soil columns from a sugarcane field. Based on usual field rates, UR and AN were added at a rate equivalent to 100 kg N ha−1, V was added at 100 m3 ha−1 (51 kg N ha−1), and CV was added at 20 m3 ha−1 (Exp. 1: 35 kg N ha−1 and Exp. 2: 56 kg N ha−1). N2O emissions were measured for 75 and 61 days after the input of fertilizers and vinasses. When mineral fertilizers were compared, the N2O-N emission factors (EFs) were: 0.08% (AN) and 1.44% (UR). Combined with N fertilizers, vinasses (CV and V) greatly enhanced the N2O emissions from soil (ranging from 0.76% to 1.5% in one study and 1.37% to 6.27% in the other). In addition, CV + N fertilizer emitted more N2O than V + N fertilizer or N fertilizer alone. However, NI reduced N2O emissions by 80% on average for vinasses (CV and V) plus N fertilizer (AN and UR) and UR alone, but not for AN alone. Since both vinasses and mineral N fertilizers are standard inputs for sugarcane production and high N2O emissions are observed when they are applied in the same area, NI should be considered for mitigation of soil N2O emissions from sugarcane used for bioenergy.