Effect of Glyphosate on Soil Enzyme

Glyphosate was one of the largest amount pesticides used in the world. It is an important scientific project to study its environmental toxicity. By simulation, the relationship between glyphosate and enzymatic activity(such as urease, invertase, phosphatase and dehydrogenase)in four tested soil types(cinnamon soil, loessal soil, sandy soil and red soil)was studied in this paper. And the ecological dose value (ED10)was calculated for assessing light contamination of soil. The results showed as follow, the non-buffer method was better to reflect real soil enzymatic activity than buffer method. Glyphosate activated the activities of urease,invertase and dehydrogenase as a whole and the most increasing rates were 190%, 1 372% and 42% respectively. While the activity of phosphatase in soil had been inhibited,and the drop rate was 35%. The reaction mechanism between phosphatase and glyphosate was fully inhibited. Glyphosate could strengthen the microbe activity because of activation of dehydrogenase, it was induced that glyphosate was a less toxicity pesticide. Ecological dose ED10 of the four soil types were 168.3, 438.5, 35.1 and 141.4 mg·kg-1, respectively. Soil enzymatic activity was more sensitive than that of biology to monitor soil polluted by glyphosate. Soil properties had a considerable influence on the toxicity of glyphosate.