ChileanJAR

A range of technologies is available to reduce greenhouse gas emissions from agricultural systems. Among these, applyingN transformation inhibitors is promising in reducing nitrous oxide (N₂O) emissions in both arable and pastoral soils.A completely randomized block design with six replicates was used to quantify the effect of urease (UI) and nitrification (NI) inhibitors on N₂O emissions and pasture production from permanent pasture in an Andisolafter autumn-applied urea. The N₂O emissions were measured periodically for 8 wkwithPVC stationary chambers. Mineral N, DM yield, N concentration, and N uptake were analyzed. Our results show that adding fertilizer (40 kg N ha^-1) significantly increased N₂O emissions by 281% over the control treatment (P <0.05) and adding N inhibitors to fertilizer N resulted in a 10%-29% reduction in emissions. Both inhibitors initially reduced nitrate-N production in the Andisol (Osorno series) either by slowing urea hydrolysis or the nitrification process. Increases in pasture yield (8%-13%), N concentration (7%-9%), and N uptake (46%-56%) were measured by addingN inhibitors with urea. Emission factors, measured under field conditions in Chile after autumn- applied urea and N inhibitors (applied alone or combined), were very low (0.052%-0.114%) compared with values reported in the literature and the Intergovernmental Panel on Climate Change(IPCC)default value (1%). Using these technologies could contribute to Chile’s nationally established goal of a 20% reduction in greenhouse gas emissions by 2020.