[N2O emissions and ammonia volatilization from leachate irrigated soils]

The effect of soil properties on N2O emissions and ammonia volatilization after leachate addition was investigated by soil S1 and S2 through incubation experiment. The conversions of soil NH4(+)-N and NO3(-)-N contents after leachate addition were evaluated as well. Soil pH dominantly determines the ammonia volatilization after leachate addition and ammonia volatilization only happens by soil S1 of alkaline nature within the first 5-day during the 10-day incubation. Approximately 3.0% leachate ammonia-N is lost via ammonia volatilization from soil S1. After being added the same amount of leachate ammonia-N, there is an approximately 20-fold gap of N2O emissions between two different soils: soil S1 and S2 (p <0.01). Soil moisture content affects the net generation rate of NO3(-)-N contents substantially and N2O fluxes are thus regulated accordingly. Compared with soils moisture content at water-filled pore space (WFPS) of 46%, N2O fluxes are elevated by 6.5, 1.8, and 2.2 times from the leachate added soil S1 without leachate irrigation (p > 0.05), the leachate added soil S1 (p > 0.05), and the leachate added soil S2 (p <0.05), respectively. During the 10-day incubation, N2O emissions cause 41.1% and 2.3% leachate NH4(+)-N loss from the leachate added soil S1 and S2, respectively. Therefore, avoiding excessively wet conditions (< 70% WFPS) and selecting acidic soil could minimize the potential N2O emissions and ammonia volatilization under leachate irrigation.