Effect of Organophosphorus Pesticides on Enzyme Activities in Alluvial Soil (Typic Ustochrepts)

Acephate, dimethoate and phosphamidon are organophosphate pesticides with high toxicity and may significantly affect soil microbial activities. However, the magnitude of this effect is unclear yet. The potential harmful effect of these pesticides on soil enzyme activity was accessed in the soil collected under controlled laboratory conditions. We examined the effect of recommended (RD) and double the recommended doses (2RD) of these pesticides on the soil enzymatic activities. The incubation study was carried out at 60% of maximum water holding capacity of the soil sample at 28±2°C for a period of 42 days. Our results indicated that high acephate, dimethoate and phosphamidon doses significantly affect enzymatic activities in the soil. Our results provide the first evidence that acephate, dimethoate and phosphamidon differentially affected the soil microbial community through inhibiting fungal and bacterial populations.