Seasonal Quality Assessment of Agricultural Soils along the Bank of Tungan Kawo Dam, Kontagora, Nigeria

Abstract

This research work studies the impacts of irrigation and other agricultural practices on the soil along the bank of Tungan Kawo dam. The experimental analysis evaluates the soil physicochemical parameters and metal (Cd, Cu, Cr, Ni, Fe, Mn, Pb and Zn) concentrations using sequential extractions. The physicochemical parameters of the soils across the sites indicated values reported for less polluted soils. Also, analysis of total metals in the soils indicated lower concentration of all metals evaluated than recommended standard limits with exception of Cd. The results of sequential extraction of heavy metal in soil sample indicated that all metals were mainly associated with the residual, Fe-MnO and organic bound fractions. The residual fraction has the maximum concentration of metals especially in cool and dry season for Cr, Cu, Ni, Pb and Zn, whereas only a small fraction of all the heavy metal is extracted in water soluble, exchangeable and carbonate bound fractions. It indicates that the bioavailability index is low. Hence, mobility of the heavy metals by the surrounding plants grown on the soils is low.