Influence of Pesticide Misuse on Soil Microbial Communities in Punjab’s Agricultural Zones

Abstract

The intensive exploitation of the soil for agricultural purposes combined with the intense use of pesticides have been the object of concerns toward their unintended impact on soil health but also on soil microbe diversity. In Punjab, Pakistan, there is a tendency among the agriculture workers to use chemical pesticide in indiscriminate manner and many times for more dosages than recommended and without adhering to advisory rules to safety practices. This study considers the impact of the pesticide abuse of soils in microbial communities of major agriculture zones of Punjab. Soil samples were taken from the fields with a history of high pesticide application and compared to low/zero pesticide applications. Microbial biomass, diversity indices and functional groups were investigated using culture techniques, but also molecular techniques (16S rRNA and ITS). Results showed a significant decrease in microbial diversity and changes in the composition of microbial communities in the pesticide-intensive fields with significant reduction in the populations of beneficial bacteria and fungi. Furthermore, long term exposure to pesticides was associated with the decrease of enzymatic activity and the nutrient cycling patterns of the soil. These findings indicate the ecological risks that are linked with the excessive use of pesticides and is another indication that the sustainability of pest management practices are needed to maintain soil microbial integrity and agricultural productivity.