硫脲对脲酶活性和尿素氮转化的试验初报

Effect of Thiourea on Urease Activities and Transformation of Urea-N

本试验研究了硫脲(TU,0.1%,0.3%,0.5%,1.0%,5.0%)不同浓度对土壤脲酶活性、土壤尿素氮转化的影响。室内培养表明,硫脲既是一种弱脲酶抑制剂又是一种硝化抑制剂。硫脲对脲酶活性和尿素水解均有显著的抑制作用,但是作用时间较短;硫脲用量为0.1%时,就起到了抑制作用,用量0.3%～1.0%之间差异不显著,用量1.0%～5.0%之间抑制效果随用量增加而加强。硫脲不仅延缓了土壤NH4+-N的释放高峰期一周,而且降低了土壤中NO3--N的富集,使NO3--N的释放高峰期向后推迟了10天。本试验条件下,土壤中的NH4+-N向NO3--N转化的时间大约为7～10天;土壤中有效氮的释放曲线主要取决于土壤NH4+-N的浓度,受NO3--N的影响次之。

We studied the effect of various concentrations of thiourea(TU,0.1%,0.3%,0.5%,1.0%,5.0%)on urease activities , transformation of urea-N in soil. Results showed that TU is a kind of weak urease inhibitor as well as a nitrification inhibitor. TU inhibited urease activity and urea hydrolysis effectively in a short time. It was effective when its application rate was 0.1%, and no difference was found between 0.3-1.0%, but the effect increased from 1.0%-5.0%. TU delayed not only the release fastigium of NH4+-N for about a week, but also decreased the enrichment of NO3--N and postponed the transformation time of NO3--N for about 10 days. It needs about 7-10 days that NH4+-N was transformed to NO3--N in soil, and the concentration of available-N depended on the concentration of NH4+-N firstly and concentration of NO3--N secondary under the condition of incubation test.