Effects of soil properties on boron sorption in savanna soils developed from sandstone and shale

Abstract

The influence of soil properties on boron (B) sorption and the relationship between B adsorption and extractable forms of Fe and Al oxides were investigated in eight soils from the Nigerian Savanna. The equilibration of B was achieved by adding 20 ml of boric acid solution containing 30 mg B g-1 soil to 4g of the soil samples shaking continuously for five hours and allowing to stand for 24 hours. Boron sorption was predicted from selected soil properties using simple and multiple regression models. Boron adsorption was positively and significantly correlated with CEC, EC, Exchangeable Ca, clay % and pH in a simple regression analysis. Multiple regression analysis including CEC, EC and OC, as independent variables, together explained 98% of the variance of B sorbed while 94% of the variance was explained by CEC, clay % and OC as independent variables. The CEC, OC and Fed accounted for 91% of the variance of the B sorbed. Even though poor correlation was observed between B sorbed and Al and Fe oxides, a combination of these and other soil properties like CEC, pH, OC, Exchangeable Ca, and clay % accounted for between 72% and 89% of the variance of the B adsorbed.

Keywords: boron adsorption, dithionite and oxalate extractable Fe and Al

Nigeria Journal of Soil Research Vol. 6 2005: 42-49