Ascription of nosZ gene, pH and copper for mitigating N2O emissions in acidic soils

Soil nitrous oxide (N2O) emissions are alarming for global warming and climate change. N2O reduction is carried out only by nosZ gene encoded N2O-reductase, which is highly sensitive to acidic pH and copper (Cu) contents. Therefore, a microcosm study was conducted to examine the attribution of soil pH management, Cu supply and nosZ gene abundance for N2O emission mitigation. Cu was applied at the dose of 0, 10, 25 and 50 mg kg  1 to three acidic soils (Soil 1, 2 and 3) without and with dolomite (0 and 5 g kg  1). Cu application and soil pH increment substantially enlarged the abundance of nosZ gene, and consequently mitigated soil N2O emissions; highest reduction with 25 Cu mg kg  1. Decline in NH4+ and subsequently accumulation of NO3 , and large contents of MBC and DOC in dolomite treated soils led to a substantial N2O reduction. The cumulative N2O emissions were lowest in the treatment of 25 Cu mg kg  1 with dolomite application for each soil. Results suggest that soil pH increment, an adequate Cu supply, and nosZ gene abundance can potentially lower soil N2O emissions in acidic soils.