通过研究脲酶抑制剂对土壤中尿素转化的影响,揭示土壤各形态氮对N2O的贡献,为控制石灰性土壤氮素损失及提高氮肥利用率提供理论依据。在室内恒温培养条件下(25℃),研究了正丁基硫代磷酰三胺(NBPT)、醋酸棉酚、硫代硫酸铵3种脲酶抑制剂对石灰性土壤各形态氮素转化与脲酶抑制率的影响,同时在人工气候室(昼夜)通过Unisense N2O微电极法对各处理土壤N2O浓度进行了原位实时监测。结果表明:尿素施入土壤1 d后50%已迅速水解,3d后完全水解。1~14d各脲酶抑制剂均可显著抑制尿素水解,尿素+NBPT处理的土壤尿素残留量显著高于其他处理,其脲酶抑制率为33.6%;NBPT处理的土壤NH+4-N含量低于其他各处理(P<0.05),在第7d分别比尿素、尿素+硫代硫酸铵、尿素+醋酸棉酚处理的降低了64.8%、63.5%、70.9%。土壤N2O浓度在第1~4 d较低,第4d后迅速上升,第6 d升至峰值,随后呈明显下降趋势(第6~9 d)。第9~14d各处理N2O的排放表现为尿素>尿素+醋酸棉酚>尿素+硫代硫酸铵≥尿素+NBPT。各形态氮与N2O浓度的通径系数分别为NO-3-N(0.641)>NH+4-N(0.356)>Urea-N(0.255),通径相关和线性相关均表明NO-3-N含量与N2O浓度呈显著正相关,是制约N2O排放的主导因素。石灰性土壤施用脲酶抑制剂可抑制土壤尿素水解转化,有效降低土壤N2O浓度,3种脲酶抑制剂中NBPT效果最佳。 By studying the effect of urease inhibitors on urea conversion in soil and revealing the contribution of various forms of nitrogen in soil to N2O, it provides a theoretical basis for controlling nitrogen loss and improving nitrogen utilization rate in calcareous soil. Under constant temperature (25 ℃), three kinds of urease inhibitors such as n-butyl phosphorothioamide (NBPT), gossypol acetate and ammonium thiosulfate were used to study the effects of urease Inhibition rate, while in the artificial climate chamber (day and night) through the Unisense N2O microelectrode method for each treatment of soil N2O concentration in situ real-time monitoring. The results showed that 50% urea was rapidly hydrolyzed after being applied to soil for 1 d, and completely hydrolyzed after 3 days. Urea hydrolysis was inhibited by all the urease inhibitors 1-14 d. The residual urea in urea + NBPT was significantly higher than that in other treatments, and the urease inhibition was 33.6%. The content of NH + 4-N in NBPT was lower than other treatments (P <0.05), and decreased by 64.8%, 63.5% and 70.9% on the 7th day compared with urea, urea + ammonium thiosulfate, urea + gossypol acetate respectively. Soil N2O concentrations were lower in the first 4 days, increased rapidly after the 4th day, and peaked on the 6th day, then decreased significantly (from the 6th to the 9th day). The N2O emission from treatments 9 to 14d showed urea> urea + gossypol acetate> urea + ammonium thiosulfate≥ urea + NBPT. The path coefficients of nitrogen and N2O concentrations were NO-3-N (0.641)> NH + 4-N (0.356)> Urea-N There is a significant positive correlation between the content of N2O and the concentration of N2O, which is the dominant factor restricting N2O emission. The application of urease inhibitor in calcareous soil can inhibit soil urea hydrolysis and conversion and effectively reduce the soil N2O concentration. The three kinds of urease inhibitors have the best NBPT effect.