Earthworm as ecological engineers to change the physico-chemical properties of soil: Soil vs vermicast

Earthworm is an important component in development and maintenance of physico-chemical properties of soil by converting biodegradable materials and organic wastes into nutrient rich vermicast. In this study, a comparison was done between the physico-chemical properties of soil and cast of Metaphire posthuma collected from botanical garden and agricultural field. M. posthuma was abundantly found in agriculture field due to its endogeic nature. It was found that earthworm of botanical garden was more efficient in cast production as compare to earthworm of agricultural field. Application of chemical fertilizer and pesticide in the field may be the possible reason for suppressing the activity of earthworm. M. posthuma increased the content of nitrogen, phosphorus and Organic Carbon (OC) while decreased the content of pH, Electrical Conductivity (EC), Total Dissolved Solids (TDS), Na, K, Ca, Li and heavy metals. Ni was one of the key heavy metals which was efficiently decreased by the M. posthuma followed by Fe (95.01%), Pb (79.31), Zn (72%) and Cr (4.87%). Cast produced by earthworm has higher nutritional value and act as excellent soil ameliorating agent.