EFFECT OF INSECTICIDES ON SOIL MICROBIAL RESPIRATION.

Laboratory experiment was conducted to study the effect of chlorpyrifos and cypermethrin insecticides on soil microbial respiration. In the experiment replicated trials were conducted on experimental field soil before application of selected insecticides using chlorpyrifos 20EC and cypermethrin 25EC at 0, 5, 10, 15, 20, 50 and 100ppm levels of fortification. The heterotrophic activities of soil micro-organisms were measured in terms of CO2 evolved after incubation period spanning from 5, 20, 35 and 50 days. The results obtained in the experiment revealed that both chlorpyrifos and cypermethrin showed gradual decrease in CO2 evolution for all levels of fortification as compare to untreated soil. But there was no adverse effect on soil microbial activity.