除草剂对水稻土微生物的影响

以阿特拉津、丁草胺和甲磺隆 3种除草剂为例 ,采用熏蒸提取法和BIOLOG碳素利用法研究了土壤中除草剂污染与水稻土微生物之间的关系及其环境意义 .结果表明以 10mg·kg-1含量施入水稻土的甲磺隆在施用初期导致微生物生物量下降 ,随培养时间的推移 ,生物量有所恢复 ;相同浓度的阿特拉津和丁草胺对水稻土微生物生物量影响不明显 .BIOLOG数据显示 ,3种除草剂施用初期 (第 2d)微生物碳源利用多样性变化不明显 ,随着培养时间的增加微生物碳源利用多样性发生变化 ,变化趋势因除草剂类型不同而异 :甲磺隆除草剂污染水稻土微生物碳源利用多样性先有明显降低 ,培养后期呈上升趋势 ;阿特拉津和丁草胺除草剂污染水稻土微生物碳源利用多样性基本不受影响 .

Effects of herbicides on soil microorganisms in a paddy soil

The dynamic relationship between herbicide contamination and microbes was investigated by means of the fumigation-extraction method and BIOLOG-carbon utilization methods. There were three different kinds of herbicides (atrazine, butachlor and metsulfuron-methyl) used as examples. The results showed metsulfuron-methyl applied at 10mg·kg^-1 significantly decreased the soil microbial biomass during the initial 10 days and then increased from 10 days to 30 days after application (DAA). The soil microbial biomass was not significantly affected by atrazine and butachlor at the same dose. BIOLOG data revealed that soil microbial diversity did not change during the initial 2 days after herbicides treatment, but a significant change of soil microbial diversity was found from 2 to 30 DAA. It was suggested that metsulfuron-methyl application caused significant decrease in the number of soil microbial community (SMC) followed by an increase. However, the number of SMC was not influenced by atrazine or butachlor.