Reducing N_2O emissions from nitrogen fertilisers with the nitrification inhibitor DMPP

摘要

Emission of nitrous oxide (N_2O) from fertilisers applied to soils comes from the process of nitrification, carried out by ammonia oxidizing bacteria (AOB) such as Nitrosomonas, and subsequent denitrification. Nitrous oxide emissions from agriculturalsoils are estimated at around 3% of the total greenhouse gas budget for Australia (Department of Climate Change 2009). A nitrification inhibitor, such as 3,4-dimethylpyrazole phosphate (DMPP) suppresses the activity of the AOB and thereby reduces nitrification and associated losses. This paper reports on a study of the impact of DMPP on N_2O emissions from four soils fertilised with urea (100-160 kg N/ha) over a range of temperatures (5-35°C) in small scale (40-150g soil) incubation studies. DMPP washighly effective at reducing N_2O emissions in one soil (Pin Gin, Qld Australia) by more than 93% at 25 and 35°C and temperature had no impact on the reductions. DMPP was less effective in reducing N_2O emissions from the other soils examined (19-89% reductions) and temperature influenced the reductions. The ability of DMPP to reduce emissions was related to the pH, organic C and mineral N status of the soils examined. The results show that DMPP has the potential to be used as a tool for mitigation ofN_2O emissions from Australian agricultural systems.