Effect of Chlorpyrifos and Malathion on Soil Microbial Population and Enzyme Activity
Abhishek Walia, Kamaljeet Sumal, Sudesh Kumari
ACTA SCIENTIFIC MICROBIOLOGY
Pesticides are chemical substances that are used for the protection of crop, plants and vegetables from various insects. Repeated applications of pesticides contaminate the soil and also disturb the soil environment by affecting soil microflora and various physicochemical properties of soil. In view of above problem, the present study examines the effect of different concentrations of chlorpyrifos and malathion (10 -1000 ppm) at different incubation period for their impact on various soil
... lora and enzyme activities in soil collected from cauliflower field of Jalandhar, Punjab (India). Lower concentration of malathion and chlorpyrifos is beneficial but higher concentration lead to reduction in microbial action in soil. After 250 ppm more declination was found in bacterial populations. Similar results were found in case of actinomycetes populations. However, use of Malathion drastically decreased the fungal population but chlorpyrifos does not have adverse effect on the number. In soil enzyme activities, low conc. has no effect on amylase but activity slightly decreased after 500 ppm. Stimulatory effect in cellulase was found at low conc. and inhibitory effect at higher concentrations. Low conc. is beneficial for P-solubilising bacteria but at higher conc. it showed deleterious effect on the phosphatase enzyme. These results concluded that these pesticides have considerably deleterious impact on soil microflora, which may be results in harmful effect on nutrients uptake and plant growth. Malathion showed more adverse effect as compared to chlorpyrifos. This research area merits enhanced future research based on molecular technique, contrary to traditional approach, which are used for quantification of net impact on soil biology. Pesticides are extensively used against a range of pests flourishing agricultural crops. Today, the demand for food is increasing as the population of the world is increasing that leads to sustainability of food production through intensive and modern agriculture attention of public health and proper utilization of natural resources. Pesticides in soil endure a variety of degradative, transport, and adsorption/desorption processes confiding on the chemical nature of the pesticide  and soil properties  that may modify the physiological and biochemical behaviour of soil microbes. It has been observed that the pesticides exposures are increasingly linked to immune suppression, hormone disruption, diminished intelligence, reproductive abnormalities and cancer. Soil is a living dynamic system containing many free enzymes, immobilized extracellular enzymes and enzymes within microbial cells. Pesticides affects many physiochemical phenomenon involving soil enzymes and microbial population like, the organic matter decomposition and nutrient cycling  . The persistence of chlorpyrifos and malathion in human and environment has been reported earlier, but their effect on soil microbes and soil enzymes has not been studied in Jalandhar district of Punjab. The impact of these two is such that the WHO has put three of two "chlorpyrifos and Malathion" to adversely affect 97% of the 1,782 species listed under the endangered species act. This study also conducted in order to aware the farmers of Punjab about the potential risk to their land and life.