Influence of copper and cypermethrin on soil enzymes activity

摘要

Influence of cypermethrin(CPM) and copper(Cu) on soil catalase activity(CTA) and urease activity(UA) were studied after 7, 14, 21, 28 and 35 days of exposure under controlled conditions. The experimental approach was based on the orthogonal design. Five concentration levels for each pollutant (CPM and Cu) were studied. The results showed that CTA in all samples declined after application of Cu without addition of CPM. When concentration of CPM ranged from 0 to 150 mg·kg -1 (no addition of Cu), the variety of CTA was in the following: restrained-activated-restrained. The combined effect of CPM and Cu on soil depends largely on concentration of pollutants. Compared to CTA, UA in all samples were restrained weakly within the first 7 days, and activated over the control sample during the following incubation time. In comparison between two enzymes, catalase appears to be more suitable to be the indicator for the combined pollution of heavy metal and insecticides as urease.