Effect of Phosphorus, Arsenic and Farmyard Manure on Arsenic Availability in Some Soils of West Bengal

A laboratory incubation study was conducted with soil samples from the selected areas of West Bengal with arsenic-contaminated groundwater, and also from an arsenic-free zone. These soils were treated with different rates of phosphorus, arsenic and well decomposed farmyard manure (FYM), and incubated for the requisite time periods. The findings showed that extractable arsenic from each soil was high at longer incubation period than at shorter period, and also in the presence of the added arsenic. The results further elucidated the interaction effect among arsenic, phosphorus and FYM in releasing both arsenic and phosphorus in the soil solution, with the FYM helping to moderate the arsenic content in the soil system, possibly by way of improving the binding of arsenic to the soil matrix. Addition of arsenic to the given soils also proved to be more effective in releasing P into the soil solution, as compared to FYM, due to competitive As-P interactions for common sorption sites in soil.