脲酶抑制剂NBPT对三种类型土壤中UAN氮溶液氮素转化和氨挥发的影响

Effects of Urease inhibitors(NBPT)on nitrogen transformation and ammonia volatilization of UAN nitrogen solution in three types of soil

室内恒温培养条件下,将N-丁基硫代磷酰三胺(NBPT)与UAN氮溶液配施,测定其氮素转化和氨挥发动态变化,研究NBPT与UAN氮溶液配施对灰漠土、潮土和红壤上氮素转化和氨挥发的影响。结果表明:(1)对比尿素,在施肥早期(6 h~7 d),UAN氮溶液能分别多提供占施氮量0%~46.67%的无机氮供应,灰漠土和潮土上UAN氮溶液的氨挥发量显著高于尿素,红壤上二者的氨挥发量无显著差异;(2)灰漠土、潮土和红壤上,NBPT的脲酶抑制率分别为5.20%~34.29%、4.10%~38.02%和3.27%~33.96%,潮土和灰漠土上的抑制效果优于红壤;NBPT配施UAN氮溶液降低了潮土上14~28 d的硝态氮含量,表观硝化抑制率为30.94%~31.42%;(3)NBPT降低了3种类型土壤上施UAN氮溶液后的氨挥发速率、氨挥发累积量和氨挥发总量,使氨挥发总量降低了14.89%~21.20%,潮土上最大,达21.20%,灰漠土上最小,最大值仅为14.89%;(4)对于NBPT不同用量,灰漠土和红壤上0.8‰NBPT与1.5‰NBPT的抑制效果无显著差异,潮土上1.5‰NBPT抑制效果显著大于0.8‰NBPT。因此,NBPT与UAN氮溶液配施,能抑制酰胺态氮的水解,降低氨挥发量,其中潮土上NBPT的抑制作用最显著,红壤上的抑制作用最弱;从应用效果和经济效益综合考虑,以0.8‰NBPT与UAN氮溶液配施最佳。

To explore the nitrogen transformation and ammonia volatilization of UAN nitrogen solution and its respective application with N-butyl thiophosphoric triamide(NBPT)on gray desert soil,fluvo-aquic soil and red soil,an indoor constant temperature incubation experiment was conducted to determine the dynamics of nitrogen transformation and ammonia volatilization when UAN nitrogen solution was applied in combination with NBPT.The results show that:(1)UAN nitrogen solution could provide 0%~46.67%more inorganic nitrogen supplies than urea during 6 h~7 d after fertilization.In the fluvo-aquic soil and gray desert soil,the ammonia volatilization of the UAN nitrogen solution was significantly higher than that of the urea,but there was no significant difference in the ammonia volatilization between them on the red soil.(2)In gray desert soil,fluvo-aquic soil and red soil,the urease inhibition rates of NBPT were 5.20%~34.29%,4.10%~38.02%and 3.27%~33.96%,respectively,and the inhibitory effect on fluvo-aquic soil and gray desert soil was better than that of red soil.NBPT reduced the nitrate nitrogen content in fluvo-aquic soil during 14~28 d,the apparent nitrification inhibition rate of the solution was 30.94%~31.42%when NBPT combined with UAN nitrogen.(3)NBPT reduced the ammonia volatilization rate,ammonia volatilization accumulation and total ammonia volatilization after nitrogen application in three soils.NBPT combined with UAN nitrogen solution reduced the total ammonia volatilization by 14.89%~21.20%,the largest figure was on fluvo-aquic soil,reaching 21.20%,the smallest figure was on gray desert soil,which was 14.89%.(4)As to different dosages,there was no significant difference for the inhibitory effect of 0.8‰NBPT and 1.5‰NBPT on gray desert soil and red soil.The inhibition effect of 1.5‰NBPT was significantly greater than that of 0.8‰NBPT on fluvoaquic soil.Considering both the application effect and economic benefit,the application of 0.8‰NBPT with UAN nitrogen solution is the optimal combination.