中文摘要：

采用室内培养方法，研究了4种常用的稻田除草剂（丁草胺、苄嘧磺隆、丁苄混剂、氯酸钾）在不同施用剂量下对稻田土壤微生物数量的影响。结果表明，4种除草剂对稻田土壤微生物均有不同程度的影响。从其影响时间来看，其影响大小依次为：氯酸钾〉丁草胺〉苄嘧磺隆〉丁苄混剂；从其影响程度来看，丁苄混剂对稻田土壤微生物群落的影响是这4种除草剂中最小的。从微生物类群的生物多样性指数来看，施药后各处理的生物多样性指数呈现先下降后恢复上升的趋势，而同一浓度的不同除草剂的处理比较，丁草胺对Shannon-Wiener指数影响较大，而丁苄混剂对其影响比较小。总之，从除草效果及对稻田土壤微生物的影响来看，丁苄混剂成为这几种除草剂的首选，其次为苄嘧磺隆，再次为丁草胺．最后为氯酸钾。

英文摘要：

The effects of butachlor, bensulfuron-methyl, the mixture of bensulfuron and butachlor, potassium chlorate on soil microbial populations in rice paddy were studied. The results indicated that the number of soil fungus, Soil actinomycin, soil bacterium population were all affected by these herbicides. In terms of effective time period to inhibit soil microbial population in paddy soil, the order from long to short of these 4 herbicides were potassium chlorate〉 butachlor〉 bensulfuron-methyl〉 the mixture of bensulfuron and butachlor. In terms of magnitude of the impact, the mixture of bensulfuron and butachlor had the lowest impact on soll microbial population. The influence of those herbicides on Shannon-Wiener diversity index of soil microorganisms changed with the applied concentration and incubation time. In general, diversity index decreased in early incubation time and then recovered 7 days after the application of these herbicides. Butachlor had great impact on Shannon-Wiener diversity index, while the mixture of bensulfuron and butachlor only had small impact, indicating that the mixture of bensulfuron and butachlor was the best choice for herbicides in rice paddy, bensulfuron-methyl was the second best, butachlor was the third and the last was potassium chlorate according to their effects on weeds and impacts on soil microbial population in rice paddy.