Impact of Acephate and Buprofezin on Soil Proteases

Abstract

Soil proteases come from various origins such as microorganisms, plants, animal excrements (urine and faeces), and dry and wet deposition. These enzymes are involved in ‘proteolysis’ which is an important process of N-cycling in many ecosystems. Nontarget effects of soil proteases have been widely investigated, and are known to be affected by various soil management practices. In this chapter we made an attempt to critically address the impact of acephate and buprofezin on proteases by treating soil samples to different concentrations of the two insecticides. Even though proteases were stimulated up to 7.5 μg g⁻¹ soil of either acephate or buprofezin, the enzyme activities were adversely affected at higher doses of insecticides (10 μg g⁻¹ soil). Also, activities of proteases increased even after two applications of the insecticides, but were declined after third application. The trend in response of the enzyme activities was similar even in soil samples amended with N-P-K. Both the insecticides in combination at higher concentrations from 5 μg g⁻¹ soil were significantly toxic resulting in antagonism towards the enzyme activity. Furthermore, insecticide combinations at graded levels in NPK-amended soil samples strongly inhibited the enzyme activity.