Effects of Chlorimuron-ethyl on Soil Enzymes Activities

Soil enzymes play important role in metabolism processes in soil system.Soil enzyme activity can reflect intensities and directions of many biochemical processes,and is affected by lots of environmental factors such as physical,chemical,biological ingredient and so on.Therefore,soil enzyme activity can be considered as a kind of ecological toxicity indicators that assess contaminative degree and effects of xenobiotic compounds on soil environment.An incubation experiment was conducted to study the effects of chlorimuron-ethyl of 0,5,10,20 and 100 ug·kg-1dry soil on soil enzymes activities.The results indicated the effects of chlorimuron-ethyl on soil enzymes activities existed significant differences.Peroxidase activity was stimulated by chlorimuron-ethyl,and the higher the concentration of chlorimuron-ethyl the greater stimulation,and then stimulation gradually decreased and stabilized at the control level in the later experiment period.Polyphemol oxidase activity was inhibited in the first days,then the inhibition gradually decreased and stabilized at the control level in the 30th day after treatment,but it was stimulated by high concentration of chlorimuron-ethyl(20 and 100 ug·kg-1).Urease and protease activities were slightly stimulated by low concentration of chlorimuron-ethyl(5 and 10 ug·kg-1),but was strongly depressed by chlorimuron-ethyl of 20 and 100 ug·kg-1.Urease activity stabilized at the control level in the 30th day after treatment,protease activity also stabilized at the control level in the 30th day except the treatment of 100 ug·kg-1.It was suggested that low dosage of chlorimuron-ethyl(low and normal field dosage) had small effects on soil enzymes activities that could recover during the period of the experiment.