Study on the degradation,adsorption-desorption and mobility of thifluzamide in soil could provide theoretical foundation for evaluating persistence of thifluzamide in soil and risk in water resource.The degradation,adsorption-desorption and mobility of thifluzamide in three kinds of soil were studied by using laboratory simulating test.The effects of soil type,moisture content,microbial and organic content on the degradation of thifluzamide were also discussed.The results showed that thifluzamide was degraded rapidly in soil,since the degradation half-lives in yellow-brown soil in Nanjing,black soil in Northeast China and red soil in Jiangxi was 9.4,17.8 and 20.1 days,respectively.The degradation of thifluzamide accelerated along with the soil moisture increased,but it decreased in 80％ moisture treatments because of microbial growth being inhibited.The degradation rates of thifluzamide accelerated 2.7 and 17.2 times respectively when the microbial and organic matter are present in soil.The adsorption capacity of thifluzamide in three kinds of soil was different,i.e.,black soil＞yellow-brown soil＞red soil,and the stronger the adsorption capacity,the weaker the desorption capacity.The adsorption coefficient showed good correlations with soil organic content,cation exchange capacity,and clay content.The adsorption free energy (△G) in three kinds of soil ranged from-22.70 to -21.30 kJ·mol-1,indicating the adsorption of thifluzamide belonged to physical absorption.The results of soil thin-layer chromatography (TLC) showed that the Rf value of thifluzamide was 0.234,0.233 and 0.224 in red soil,yellow-brown soil,and black soil,respectively.These results indicated that thifluzamide was difficult to move in three kinds of soil.The results of soil column leaching test showed that thifluzamide with poor mobility in three kinds of soil is hard to leach,which indicated that it is not easy to bring pollution in the underground water by leaching.%研究噻呋酰胺在土壤中的降解、吸附-解吸及移动特性,有利于评价噻呋酰胺在土壤环境中的持效性,可为其安全使用及对水资源的风险性评价提供理论依据.采用室内模拟方法研究了不同土壤类型、土壤含水量、土壤微生物和有机质含量对噻呋酰胺在土壤中降解的影响以及噻呋酰胺在土壤中的吸附、解吸及移动特性.结果表明,噻呋酰胺在3种土壤中均属于易降解,噻呋酰胺在南京黄棕壤、东北黑土、江西红壤中的降解半衰期分别为9.4、17.8、20.1 d.随着土壤湿度增加,噻呋酰胺的降解速率加快,当土壤湿度为饱和含水量80％时,微生物生长将受到抑制,降解速率减慢.土壤中微生物和有机质能加快噻呋酰胺降解,在微生物和有机质存在的条件下噻呋酰胺降解速率分别提高2.7倍和17.2倍.噻呋酰胺在3种土壤中的吸附能力为东北黑土＞南京黄棕壤＞江西红壤,吸附能力越强,解吸附能力越弱;土壤有机质含量、阳离子代换量和粘粒含量与吸附系数具有良好的相关性.噻呋酰胺在土壤中的吸附自由能在-22.70～-21.30 kJ·mol-1之间,属于物理吸附.薄层层析研究表明,噻呋酰胺在江西红壤、南京黄棕壤、东北黑土中的Rf值分别为0.234、0.233、0.224,均属于不易移动.土柱淋溶试验结果表明,噻呋酰胺在3种土壤中均属于难淋溶,不易通过淋溶作用对地下水造成污染.
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