Interaction Effects of Insecticides on Enzyme Activities in Black Clay Soil from Groundnut (Arachis hypogaea L.) Fields

C Nasreen,V Rangaswamy,Jaffer Mohiddin,A Rekha Padmini,P Ramanamma,M Srinivasulu

doi:10.5755/j01.erem.60.2.671

Abstract

In practice pesticides are extensively used in agriculture as a part of pest control strategies. Two insecticides, endosulfan (organochlorine) and profenophos (organophosphate), were assessed for their effects on the activities of protease (in terms of tyrosine formed from casein) and urease (as ammonia released from urea) in soil, collected from a fallow groundnut field by applications of insecticides at normal field rates and at higher concentrations (1.0, 2.5, 5.0, 7.5, 10.0 kg ha-1), in a laboratory study. The results showed a strong positive influence on protease and urease enzyme activities in soil treated with 2.5 and 5.0 kg ha-1 dry soil and they were significantly (P ≤ 0.05) higher than the control over the course of incubation. In soil treatment, there was a significant increase in protease and decrease in urease activities after 24h of incubation which continued up to 20 days. However, a significant decrease in both protease and urease enzyme activities was observed in 30 and 40 days of incubation.DOI: http://dx.doi.org/10.5755/j01.erem.60.2.671

Highlights

Since several decades, xenobiotic substances have been widely used in agriculture as a part of pest control strategies with the growing use of pesticides
Our investigation has revealed that protease activity has more drastically decreased at higher concentrations (5.0, 7.5 10.0 kg ha-1) of endosulfan and profenophos treated soils than the untreated controls throughout the experiment (Table 2), suggesting that the enzyme is rather sensitive to endosulfan and profenophos
Urease follows the same trend, a stimulatory effect of endosulfan and profenophos was observed at 10-50 ppm concentrations with individual increments of two insecticidal treatments on the control, they were 7-31% and 12-30 % in black clay soil after 10 days of incubation (Table 3)

Summary

Introduction

Xenobiotic substances have been widely used in agriculture as a part of pest control strategies with the growing use of pesticides. The issue of an impact of these chemicals on the composition of soil microorganisms and the processes they direct have received more attention (Andrea et al 2000, Baxter and Cummings 2008) and their background levels in the environment have increased greatly. As a consequence, these agrochemicals (biotoxicants) have been found in numerous natural systems and have a great impact on environment quality (Madhun and Freed 1990). The present day agriculture involves abundant cultivation of the crop because of its vital role in edible oil seeds production (Kori et al 2002). When an anthropogenic factor is released deliberately or accidentally into the environment, about 0.1% of it reaches the target organism while the remaining 0.99% reaches the soil causing trouble to local metabolism or enzymatic activities (Carriger et al 2006; Pimentel 1995 Engelen et al 1998; Liu et al 2008; Topp et al 1997), and disturbs the soil ecosystem and may affect human health by entering the food chain, and it has raised a considerable public concern

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