Key factors, soil N processes, and nitrite accumulation affecting nitrous oxide emissions
Although there are many studies on how environmental conditions and agricultural practices affect nitrous oxide (N2O) emissions, it is not well understood how N transformation processes are involved in mitigation strategies.
In the November–December 2016 issue of the Soil Science Society of America Journal, researchers conducted a series of laboratory incubation experiments and examined the effects of N (urea) application rate, soil water content, temperature, biochar incorporation, urease inhibitor (Agrotain Ultra), and nitrification inhibitor (N-Serve 24) on N2O emissions and N transformation dynamics in a sandy loam soil.
In addition to N application rate, soil water content is a profound factor impacting N2O emissions. Much higher emissions were found in soil above water-holding capacity (WHC) than those below. They also revealed that the linear correlation between soil nitrite (NO2–) concentration and N2O emissions was significantly different between two distinct ranges (above vs. below WHC). Biochar and the inhibitors all reduced total N2O emissions >70%. However, all data on N transformation and pH support that the treatment (except the high water content) effects on N2O emissions are mostly limited to a couple of weeks, indicating the challenges in mitigation.
Read the full article in SSSAJ. Free preview Jan 18 - Jan 25.