摘要：Better understanding of process controls over nitrous oxide (N2O) production in urine-impacted ‘hot spots’ and fertilizer bands is needed to improve mitigation strategies and emission models. Following amendment with bovine ( Bos taurus ) urine (Bu) or urea (Ur), we measured inorganic N, pH, N2O, and genes associated with nitrification in two soils (‘ L ’ and ‘ W ’) having similar texture, pH, C, and C/N ratio. Solution-phase ammonia ( sl NH3) was also calculated accounting for non-linear ammonium (NH4+) sorption capacities (ASC). Soil W displayed greater nitrification rates and nitrate (NO3−) levels than soil L , but was more resistant to nitrite (NO2−) accumulation and produced two to ten times less N2O than soil L . Genes associated with NO2− oxidation ( nxr A) increased substantially in soil W but remained static in soil L . Soil NO2− was strongly correlated with N2O production, and cumulative ( c- ) sl NH3 explained 87% of the variance in c- NO2−. Differences between soils were explained by greater sl NH3 in soil L which inhibited NO2− oxidization leading to greater NO2− levels and N2O production. This is the first study to correlate the dynamics of soil sl NH3, NO2−, N2O and nitrifier genes, and the first to show how ASC can regulate NO2− levels and N2O production.
