Assessment of Physico-Chemical and Heavy Metals Properties of some Agricultural Soils of Awing-North West Cameroon

Abstract

This research work was aimed to assess the quality of agricultural soils of Awing-North West Cameroon by elucidating some physicochemical properties and heavy metals in the soils. Agricultural yields in Awing have witnessed a decline in recent years and farmers have repeatedly used fertilizers to improve on their agricultural yields. It is thus important to test the soil in order to ensure not only high productivity but its quality as well and suggest methods to increase agricultural yields, while preventing soil and water pollution. Twenty soil samples were randomly collected from four sites, Achialum, Meupi, Nepele and Ala’amiti, in Awing and analysed for physicochemical and heavy metal properties using standard methods. Results showed that all the soils had low bulk densities (0.76-0.89 g cm-3), low pH values (4.1-6.0), low electrical conductivities (0.02 – 0.11 mS cm-1), low available phosphorus (1.55-14.26 mg kg-1) and the soil textural class was dominated by loam. The mean available concentrations of heavy metals ranged from 0.24-2.73, 0.64-5.13, 13.79-34.51, 29.45-92.27, 0.00-0.80, 0.24-4.54, 0.68-1.39, 0.30-0.47 mg kg-1 for Zn, Cu, Mn, Fe, Pb, Ni, Cr and Cd respectively. Results of heavy metal analysis showed that the soils were contaminated to different levels (above FAO/WHO limits) by the different heavy metals. Natural origins, fertilizer application and domestic waste were identified as the major sources of heavy metals in the soils. Future research should focus on the development of methods to quantify lime-enhanced mobilization of nutrient ions and lime-induced immobilization of heavy metals in these soils