氯甲基吡啶与NBPT配比对石灰性土壤氮素转化的影响

为了筛选适宜的脲酶抑制剂与硝化抑制剂组合,本试验通过在室内模拟培养条件下,研究不同浓度的NBPT与Nitrapyrin配比对石灰性土壤氮素转化的影响。结果表明:尿素施入土壤1 d后80%已迅速水解,在5 d后已完全水解。在1-14 d不同浓度的NBPT均可显著抑制尿素水解(P0.05),且10%o NBPT可高效作用14 d,其脲酶抑制率为51%。添加抑制剂延缓了铵态氮的转化过程,各施肥处理土壤NH_4~+-N含量分别在第7、14、21天达到峰值,而各抑制剂处理NO_3~--N含量呈线性缓慢上升趋势。添加抑制剂各处理均降低了土壤氮素损失,相比单施尿素处理分别降低14%、22%、26%、28%(P0.05)。NBPT 5‰+Nitrapyrin可有效抑制尿素水解,减缓氮素转化过程,减少石灰性土壤氮素损失。

Effect of the Ratio of Nitrapyrin and NBPT on Nitrogen Transformation in Calcareous Soil

In order to screen out the optimal combination ratio of nitrification inhibitor （Nitrapyrin） and urease inhibitor （NBPT）,a soil incubation experiment was carried to study the response of soil mineral N transformation to 2.5%0 nitrapyrin combined with 2%0,5%0 and 10%o NBPT （n-（n-butyl） thiophosphoric triamide） in calcareous soil.The results showed that,the 80% applied urea bad been hydrolyzed on the first day after urea amendment,and all the applied urea had been totally hydrolyzed on the fifth day after urea application.It was observed that different concentrations of NBPT treatment all exerted a significant inhibition effect （/~〈0.05） on urea hydrolysis process in 1-14 day incubation duration. The urease inhibition rate of 51~/6 was obtained with 10~/oo NBPT treatment,and its effective role could last for 14 days. Soil mineral nitrogen transformation process was been retarded with N inhibitor application, for instance, the time to reached peak for soil NHa~-N was 7 days with urea treatment,14 days with Urea＋Nitrapyrin and 21 days for Urea＋Nitrapyrin＋10%o NBPT treatment,respectively,while soil NO3--N content showed a slow increasing trend. In contrast to Urea treatment,soil N loss rates decreased by 14% with Urea＋ Nitrapyrin,by 220/6 with Urea＋Nitrapyrin＋2~/oo NBPT,by 26% with Urea＋ Nitrapyrin＋5%oNBPT and by 28% with Urea＋Nitrapyrin＋10%o NBPT treatment, respectively,which suggesting that N inhibitors significantly decreased soil N loss （P〈0.05）.In conclusion,NBPT 5%0 combined with Nitrapyrin exerts a significant role on inhibiting urea hydrolysis, retarding soil N transformation process as well as decreasing soil N losses in calcareous soil.