Effect of 68% Mancozeb on Soil Microorganism's Population and Respiration

Effects of 68% mancozeb in the concentrations of 0,0.5,2.5,5.0 mg kg-1 on soil microorganism population and soil respiration intensity were investigated.Results showed that bacterial,fungal and actinomycetous growth and soil respiration were stimulated when mancozeb concentration was 0.5 mg kg-1.But under the high concentration of mancozeb,microorganism's population and respiration of soil were all inhibited.Higher concentration caused greater influence in the early days.But as time went by and pesticide content in soil was decreased,microorganism's population and respiration of the soil treated with mancozeb was equivalent to that in CK.According to risk assessment,mancozeb should belong to non-poisonous pesticide.