双唑草腈在3种典型土壤中的降解

为明确双唑草腈在环境中的降解行为特性，采用室内模拟试验方法，分别研究了积水厌气、好氧和灭菌条件下，双唑草腈在紫色土、水稻土及红壤3种典型土壤中的降解特性。结果表明:双唑草腈在3种土壤中的降解均符合一级反应动力学方程，好氧条件下，其在紫色土、水稻土及红壤中的降解半衰期分别为13.4、10.1和31.1 d，且降解速率与土壤中有机质和黏粒含量呈正相关；不同条件下的降解速率依次为积水厌气 > 好氧 > 灭菌，说明双唑草腈在土壤中的降解一定程度上受水解和微生物活性的影响；在一定的土壤持水量范围内，双唑草腈在土壤中的降解速率随土壤含水量增加而加快。研究表明，双唑草腈在稻田淹水条件下施用降解较快，残留期较短。所得结果可为双唑草腈的合理使用及其环境安全性评价提供科学依据。

Degradation of pyraclonil in three typical soils

To clarify the degradation behavior of pyraclonil in the environment. The indoor simulation test method was used to study the degradation characteristics of pyraclonil in purplish soil, paddy soil and red soil under the conditions of anaerobic, aerobic and sterilized. The results showed that the degradation of pyraclonil in those three soils accorded with the first-order kinetic equation. Under aerobic conditions, the degradation half-lives in purplish soil, paddy soil and red soil were 13.4 d, 10.1 d, and 31.1 d, respectively. And the degradation rates were positively correlated with the organic matter and clay content in the soils. The degradation rates under different conditions were in the order of anaerobic > aerobic > sterilization, which indicated that the degradation of pyraclonil in the soil was affected by the hydrolysis and microbial activity. Within a certain range of soil water holding capacity, the degradation rate of pyraclonil in the soil was improved with the increase of soil water content. This study demonstrated that the degradation rate of pyraclonil was relatively fast and the residue period was short under the condition of flooding in paddy field. This work provided a scientific basis for the rational use of pyraclonil and its environmental safety evaluation.