除草剂单用与混用对土壤微生物活性的影响

Influences of Single and Combined Herbicides on Soil Microbial Activity

在实验室条件下,通过观测投加农药土壤中的细菌、真菌数和土壤呼吸强度的变化,研究了灭草松、莠去津、灭草松+莠去津及灭草松+莠去津+表面活性剂对土壤微生物活性的影响。结果表明,莠去津、灭草松在10倍推荐用量下会使土壤细菌数略有减小,真菌数略有增加,细菌/真菌数之比减小;莠去津+灭草松与他们单用时对土壤呼吸的影响无显著差别,但添加表面活性剂后,土壤呼吸增强且持续时间延长。

Effect of pesticides on the soil microbial activity is considered as an indicator of their ecologic security. The side effects of bentazone and atrazine in mono- component and multi- component systems on the soil microflora were monitored by incubating herbicides in near rhizhosphere and control soil under 30 ℃ and 60% maximal water holding capacity in dark over 50 days. During the period of incubation, the microbial population and evolution of CO2 were monitored simultaneously at frequent intervals. The obtained results indicated that 10 times field- rate application of atrazine or bentazone resulted in a slight increase in bacterial population, a slight decrease in fungal population and an apparent decrease in the ratio of total bacterium to fungi. There was no significant difference between the effects of single herbicide and their mixture on soil respiration, but addition of surfactant in herbicides complex could enhance the soil respiration.