Effects of 3,5-Dimethylpyrazole on Soil Urea-N Transformation and NO-N Leaching
3,5-二甲基吡唑对尿素氮转化及NO-3-Ｎ淋溶的影响

With the combination of incubation test and field experiment, the effects of the new nitrification inhibitor 3,5-dimethylpyrazole on urea-N transformation and NO3- leaching loss from corn field were studied. The results showed that DMP could temporally retard the hydrolysis of urea after its application, but strongly inhibit the process of ammonium oxidation for a longer time, and the inhibitory efficiency was enhanced with increasing DMP dose. Compared with CK, soil NH4+-N content in treatments DMP1 (0.0025 g/kg), DMP2 (0.01 g/kg) and DMP3 (0.025 g/kg) was increased by 5.17, 9.36 and 11.04 times on the 10th day of incubation, while soil NO3--N content was decreased by 33.30%, 61.19% and 73.72% on the 14th day, respectively. The application of DMP could also decrease soil NO2--N content by 95.77% ~ 96.13% on the 3rd day of incubation, increase soil microbial biomass N from 14d to 56d, and reduce the total amount of soil mineral-N significantly with increasing DMP dose after 10 days of incubation. The corn field experiment indicated that, compared with CK, the soil NO3--N content of 40 ~ 100 cm layer in treatment DMP was decreased by 28.77% and 44.70% in 2004 and 2005, respectively. DMP application might be an effective means for regulating urea-N transformation and mitigating nitrogen pollution.