Changes in the metabolic activities of two agricultural soils as influenced by the pesticides and insecticides combination

- Soils showed 6-85% invertase activity with pesticides and 3-58% with combination.
- Maximum enzyme activity (57%) over control in red soil and at 2.5 kg ha−1 in black soil.
- Pesticides promoted mineralization showed high level of Nitrogen mineralization in soils.

Application of pesticides (thiram, difenoconazole, deltamethrin and profenofos) and insecticide combinations (profenofos + cypermethrin and deltamethrin + endosulfan) at concentrations ranging from 0.0 to 10.0 kg ha−1 were tested for their non-target effects towards the activities of protease, invertase, sulphur oxidation, and nitrogen mineralization in two agricultural soils of groundnut under laboratory conditions. In this study, protease activity was measured in terms of tyrosine equivalents formed from casein, and the invertase activity was measured in terms of glucose formed from sucrose. We found pronounced mineralization of peptone-nitrogen and sulphur oxidation in the soil samples treated with 2.5-5.0 kg ha−1 of the insecticide combinations and individual pesticides. Soil samples treated with 2.5 kg ha−1 -5.0 kg ha−1 of the insecticide combinations and individual pesticides have shown increased invertase and protease activity at 20th day and then decreased with increasing period of incubation. From the obtained results it was concluded that the influence of these insecticide combinations and individuals on enzyme activity, nitrogen mineralization, and sulphur oxidations were dose dependent.