低质量浓度除草剂2，4滴丁酯处理对土壤动物群落结构的影响

土壤动物是土壤污染的敏感指示生物，对土壤环境变化表现出比较灵敏的反映，为了解低质量浓度除草剂对土壤生态系统的影响，进一步推动除草剂使用的安全性评价研究，采用除草剂2,4滴丁酯对土壤动物群落进行室内染毒模拟试验，参照农田施用常规参考质量浓度，设置4个质量浓度梯度和一个不喷施除草剂的对照质量浓度，质量浓度最高限于参考喷施质量浓度的3~4倍，一次染毒后分别于12、24、48和72 h后对土壤动物进行分离并对群落结构特征进行分析。试验共获得土壤动物18655个，隶属于2门，4纲，12目，群落结构分析结果表明低质量浓度2,4滴丁酯导致土壤动物个体数和类群数有所减少，但减少的程度并不大。个体数量变化与质量浓度增高之间呈现较明显负相关（r=-0.856，P〈0.05），种类数变化与质量浓度之间不具有明显的相关性，土壤动物种类数的减少主要取决于稀有类群和极稀有类群，数量的变化则主要是优势类群和常见类群的增减。2,4滴丁酯的施加使得土壤动物群落多样性指数和优势度指数降低，均匀度指数增高。土壤动物个体数量和类群数量变化与染毒后经历的时间之间并未表现出明显的规律性，染毒后不同时间土壤动物优势度指数相差较大，而多样性指数和均匀度指数在不同历时时间段内相差不大。综合各分析结果能够看出，低质量浓度2,4滴丁酯处理会对土壤动物群落造成一定影响，但影响程度并不大。

Effects of low concentrations of 2,4-D butyl ester on the community structure of soil animal

As a sensitive biological indicator of soil pollution, soil animals react quickly to soil environmental changes. In order to understand the impacts of herbicides of low concentrations on soil ecosystem and promote the safe use assessment of herbicide, the experiment simulating pollution of the soil animal community with herbicide 2,4-D butyl ester was taken indoors. A concentration without herbicide as control group and 4 concentration gradients in the range of 3 to 4 times of the reference concentration were conducted on the samples at the same time. The soil animal community structures were analyzed respectively after 12 h, 24 h, 48 h and 72 h pollution. A total of 18655 soil animals, belonging to 2 phyla, 4 classes, 12 orders were captured in the test. The soil animal community structure analysis results show that the individual and group numbers of soil animals decreased in the samples of using low concentration 2,4-D butyl ester, however the reduction extent was not noticeable. The individual numbers of soil animals show obvious negative correlation （r = -0.856, P 〈0.05） with the concentration while the species numbers are not. The changes of individual numbers of soil animals were mainly depended on dominant and common groups and the group numbers were chiefly influenced by the rare species. The diversity and dominance index reduced accordingly by the low concentration of 2,4-D butyl ester influence, while the evenness index increased. The individual numbers and species of soil animals have no obvious relation with the contamination duration. The difference of dominance index enlarged and the diversity index and evenness index have little difference at different time. Comprehensive analysis shows that the treatment of low concentration of 2,4-D butyl ester has influences to the soil animal community, but the impact is not serious.