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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。
The effects of different concentrations of thiourea (TU, 0.1%, 0.3%, 0.5%, 1.0%, 5.0%) on soil urease activity and soil urea nitrogen transformation were studied. In-house culture showed that thiourea is both a weak urease inhibitor and a nitrification inhibitor. Thiourea had a significant inhibitory effect on urease activity and urea hydrolysis, but the action time was short; when the amount of thiourea was 0.1%, it had an inhibitory effect, and the difference was not significant at the dosage of 0.3% -1.0% ~ 5.0% inhibitory effect with the dosage increased. Thiourea not only delayed the release peak of soil NH4 + -N for a week, but also decreased the accumulation of NO3 - N in the soil, postponing the release of NO3 - N for 10 days. Under the experimental conditions, the conversion time of NH4 + -N to NO3 - N in soil is about 7-10 days. The release curve of available nitrogen in soil mainly depends on the concentration of soil NH4 + -N and is affected by NO3 - N Second.