Phosphorus adsorption isotherms in relation to soil characteristics of some selected volcanic affected soils of foumbot in the west region of Cameroon

Abstract

This study evaluated volcanic influenced soils from the Foumbot areas of Mbankouop, Paponoun, Monoun and Baigom plain for their physico-chemical soil properties and their phosphorus (P) sorption characteristics. The fact that P in soils is not readily available to plants necessitates investigation in order to determine the quantities to be added and avoid excesses which can lead to water pollution by fertilizers. The Freundlich, Langmuir, Temkin and Van Huay adsorption isotherms were used to describe P adsorption processes. The adsorption isotherms showed that rates of P adsorption increased with increased concentration of P, but at a certain level of higher concentration, the level of P became almost constant, because the soil had no more capacity to adsorb. P adsorption capacity decreased in the order Monoun>Paponoun>Mbankouop>Baigom plain with maximum adsorption values of 3020.86, 2174.04, 1949.12 and 497.90 mg kg-1soil recorded, respectively. Accuracy of fitness of data of the four samples into the adsorption equations increased in the order Langmuir, Van Huay, Temkin and Freundlich with coefficient of determination (R2) values of 0.819, 0.902, 0.967 and 0.972, respectively. The capacity of each sample to adsorb P was significantly correlated with amorphous iron content (r = 0.949*), but weakly negatively correlated with the available P, exchangeable bases and silt content of the soils. Management practices involving the use of organic materials and liming as a basis for P sorption reduction will be useful for crop production in Foumbot.