Abstract: Under submerged incubation with different bensulfuron-methyl treatments (0-750 g/hm²), dynamics of soil microbial activity and biochemical characteristic in a waterlogged paddy soil were studied. Slow decrease in the soil microbial biomass (phospholipid content) was found with the prolongation of incubation time in all treatments, while the soil microbial biomass (phospholipid content) decreased with increasing of herbicide bensulfuron-methyl level against control. A consistent decline in the abundance of heterotrophic bacteria was observed with the continuance of incubation in all treatments, while the abundance of heterotrophic bacteria rapidly decreased with increasing of bensulfuron-methyl level against control, especially at higher levels (375 and 750 g/hm²). A consistent decrease in soil electron transport system (ETS)/dehydrogenase activity was found during first week in all treatments, while later on it increased. Soil electron transport system activity also decreased with increasing of herbicide bensulfuron-methyl level against control. A consistent increase in soil phenol content was measured during first week in all treatments, while later on it decreased. Soil phenol content rapidly increased with increasing of herbicide bensulfuron-methyl level against control, especially at higher levels (375 and 750 g/hm2). A consistent but non- significant depletion in the soil protein content was noticed with the prolongation of incubation period in all treatments, while a slight but consistent (non-significant) increase in the soil protein content was observed with the increased herbicide concentration irrespective of the incubation stage.

Key words: herbicide, soil microbial activity, biochemical characteristic, paddy soil

摘要： 在室内培养试验条件下， 研究了不同剂量苄嘧磺隆（0~750 g/hm[sup]2[/sup])对淹水稻田土壤中微生物活性和生物化学特性的影响。结果表明,所有处理中土壤微生物生物量(磷脂含量)随培养期延长而缓慢减少，与对照相比，土壤微生物生物量(磷脂含量)随苄嘧磺隆增加而有所减少。所有处理中异养型细菌（富营养菌和贫营养菌）随培养期延长持续减少，与对照相比土壤中异养型细菌随苄嘧磺隆剂量增加而快速减少，尤其是苄嘧磺隆剂量较大（375和750 g/hm[sup]2[/sup]）的土壤中异养型细菌显著减少。土壤电子运输系统/脱氢酶活度在第1周内随培养时间延长持续下降，之后随培养时间延长而增强。与对照相比，土壤电子运输系统活度也随除草剂苄嘧磺隆施用剂量的升高而下降。第1周内土壤酚含量随培养时间延长持续增加，之后随培养时间延长而减少。 与对照相比，土壤酚含量随苄嘧磺隆施用剂量的增加而快速增加，尤其是苄嘧磺隆剂量较大（375和750 g/hm[sup]2[/sup]）的土壤中酚含量显著增加。在所有处理中，土壤中蛋白质含量随培养时间的延长缓慢减少，但不显著。土壤蛋白质含量随除草剂苄嘧磺隆剂量增加而略微增加，但不显著。

关键词: 除草剂, 土壤微生物活性, 生物化学特性, 水稻土