脲酶抑制剂与硝化抑制剂对稻田氨挥发的影响

摘要

采用密闭室间歇通气法和15 N标记技术研究了尿素施入稻田后氨挥发损失特征以及脲酶抑制剂（ N-丁基硫代磷酰三胺，NBPT）和硝化抑制剂（3，4-二甲基吡唑磷酸盐，DMPP）对稻田氨挥发损失的影响。结果表明，稻田施用尿素后第4天氨挥发速率达到峰值，氨挥发损失主要发生在施肥后21天内。与单施尿素处理相比，添加NBPT处理的氨挥发速率峰值降低27.04％，累积氨挥发损失量降低21.65％；NBPT与DMPP配施时，氨挥发速率峰值降低12.95％，累积氨挥发损失量降低13.58％；而添加DMPP时，氨挥发速率峰值增加23.61％，累积氨挥发损失量与单施尿素的差异不显著。相关性分析表明，地表水中铵态氮浓度和pH值与氨挥发速率均达极显著正相关，说明二者是影响氨挥发速率的主要因素，而气温、地温和水温与氨挥发速率的相关性不显著。与单施尿素相比，添加脲酶抑制剂可显著增加稻谷产量。脲酶抑制剂与硝化抑制剂配合施用可更有效地提高氮肥的回收率。综合降低氨挥发、提高水稻产量及地上部氮肥回收率的效果，添加脲酶抑制剂以及脲酶抑制剂与硝化抑制剂配施的两个处理效果较为理想，硝化抑制剂不宜单独添加。%With the technique of stable isotope 15 N-traced urea, a field experiment was conducted to determine the effects of urease inhibitor(UI) and nitrification inhibitor(NI) on losses of ammonia(NH3) volatilization from paddy fields .The urease inhibitor NBPT [ N-( n-butyl ) thiophosphoric triamide ] and nitrification inhibitor DMPP [3, 4-Dimethyl-1H -pyrazole phosphate ] were added to urea ( U) with a rate of 10, 000 mg/kg urea.A randomized experimental design with five treatments and three replicates was used :1 ) CK ( no N fertilizer );2 ) Urea only;3) Urea +NBPT;4) Urea +DMPP;5) Urea +NBPT +DMPP.The fertilizer was broadcast in rice field before the transplanting of rice seedlings .The results show that the losses of NH 3 volatilization from the nitrogen fertilizers last for 21 days and the maximum volatilization turns up in the 4th day after fertilization. Compared to the urea treatment , the peak of volatilization and cumulative loss of NH 3 from addition of NBPT significantly decreased by 27.04%and 21.65%, and that from combined addition of NBPT and DMPP decreased by 12.95% and 13.58%, respectively . On the contrast , adding DMPP alone enhanced the peak of NH 3 volatilization by 23.61%, the NH3 losse did not increase significantly .NH3 volatilization rate is significantly correlated with the concentration of NH 4+-N and pH of floodwater ( P<0.01 ) , not significantly correlated with the temperatures of air, soil and floodwater.Therefore, the NH4+-N concentration and pH of floodwater are the dominating factors influncing NH 3 volatilization rate .Compared to the normal urea , the two treatments added with NBPT increase yield of rice significantly , and combination of NBPT and DMPP markedly improves the recovery of applied N in the above-ground parts .In summary , the effects of urea added with urease inhibitor or combination of urease and nitrification inhibitors are better than urea added with nitrification inhibitor alone , in view of reduction of NH3 volatilization , increase of rice yield and the recovery of applied N in the above-ground parts .