Effects of the nitrification inhibitor nitrapyrin and mulch on N2O emission and fertilizer use efficiency using 15N tracing techniques

Abstract

Nitrous oxide (N2O), is a potent greenhouse gas (GHG) that shares 7% of global warming around the world. Among different sources, agricultural systems account for approx. 60% of global anthropogenic N2O emissions. These N2O emissions are associated with the activity of nitrifiers and denitrifiers that contribute to >4 Tg (teragrams) N2O-N emission per year. Application of nitrogen (N) fertilizers and manures in agricultural fields plays an imperative role in this regard. On the other hand nitrification inhibitors are an effective approach to minimize N2O-N emissions from agricultural fields. Here we examined the effects of applying urea with a nitrification inhibitor (Ni) nitrapyrin and mulch (Mu) on urea transformation, nitrous oxide (N2O) emissions, grain yield and nitrogen (N) uptake efficiency. The treatments include a control (zero N), urea (U) applied at 200 kg N ha−1, U + Ni (Ni applied at 700 g ha−1), U+ Mu (Mu applied at 4 t ha−1) and U + Ni + Mu. The N2O emission factor (EF) was 66% and 75% when U and Mu were applied, respectively. Yield-scaled N2O emissions were lower in U and Mu by 45% and 55%, respectively. The Ni coupled with Mu enhanced urea-15N recovery by 58% and wheat grain yield by 23% and total N uptake by 30% compared with U alone. In conclusion, Ni usage is an effective strategy to mitigate N2O emissions under field conditions.