Abstract:

【Objective】 Omethaoate is a major pesticide that is widely used in agricultural production in the world, and it has made an important contribution to grain production increase. Its negative influence of widely use on environment pouation has been concerned by peoples as the environment is worse and the quality of agricultural products are reduced. It is necessary and important to study soil ecological toxicity of pesticides in theory and application. 【Method】 By indoor simulation, soil enzyme activities, for example, soil invertase, urease and alkaline phosphatase, which catalyze carbon, nitrogen and phosphate nutrient cycling, were assayed in soil samples polluted by different omethaoate concentrations. 【Result】 Omethaoate could remarkably inhibit soil urease activity, their relationship reached significant and remarkable significant correlation between soil urease activity and omethaoate conentration. Soil urease activity could be one of the indexes to monitor soil pollution by omethaoate. The model U=A/(1+B×C) was a better regression equation and it showed their reaction mechanism was a full inhibition between soil urease and omethaoate. The acquired critical concentrations were 0.32, 2.88 and 11.43 g a.i.•kg-1 respectively with soils polluted slightly, medium and seriously by omethaoate. The maximum change was less than 18.61% and 8.36% for soil invertase and alkaline phosphatase activity respectively. Soil invertase and alkaline phosphatase were not sensitive to omethaoate. 【Conclusion】 Soil urease is better than invertase and alkaline phosphatase to be one of indexs of soil polluted by omethaoate. The relationship between soil enzymes and pesticides is influenced by many factors such as enzyme types, pesticide variety and soil properties.

Key words: omethaoate, soil enzyme, ecological dose