Effect of Acetamiprid on Enzyme Activity in Selected Soils of Karnataka

The impact of acetamiprid on selected soil enzymes dehydrogenase, urease and phosphatase was studied using surface layer (0-15 cm) samples of movement studies. The samples were taken at different interval (10, 20, 30, 45 and 60 days) under field capacity and the enzyme activities were analyzed for Kodagu, Bangalore and Chamarajanagar soils of Karnataka. Highest inhibition was found on 10^th day incubation compared to initial activity in all the enzymes. The increased activity of all the three enzymes was observed from 20^th day incubation and reached maximum in 60^th day incubation. The highest dehydrogenase activity was recorded in Bangalore soil (58.93 μg TPF g^-1 soil h^-1) and the lowest activity was recorded in Kodagu soil (16.05 ig TPF g^-1 soil h^-1). The highest urease activity was recorded in Bangalore soil (356.66 ig urea g^-1 soil h^-1) and the lowest activity was recorded in Kodagu soil (341.81 ig urea g^-1 soil h^-1). The highest activity of acid phosphatase activity was recorded in Kodagu soil of pH 5.32 (6.23 μg pnitrophenol hydrolyzed g^-1 soil h^-1) followed by Bangalore (4.86 μg p-nitrophenol hydrolyzed g^-1 soil h^-1) and Chamarajanagar (4.63 μg p-nitrophenol hydrolyzed g^-1 soil h^-1) ,respectively. The alkaline phosphatase activity in soil was also high in Chamarajanagar soil of pH 8.1 (7.05 p-NP hydrolyzed μg^-1 soil h^-1), followed by Bangalore soil (5.29 μg p-NP hydrolyzed g^-1 soil h^-1) and Kodagu soil (3.85 μg p-NP hydrolyzed g^-1 soil h^-1).