Abstract
This study was conducted to assess Phosphorous (P) release in soils derived from three parent materials, Shale, Sandstone and Basalt and to find the best fitting models to describe P release to 0.01m CaCl2 extraction in a duration of 1 – 72 hours at different concentration of P added, (0, 20 40 and 80 mgl-1p). Two 20g of soil were suspended in 20ml of 0.01m CaCl2 and equilibrated at 250C. The suspensions were shaken for 1 hour and left for the equilibrating time before the suspense was centrifuged for 10 minutes and P in the extract was determined. The physical and chemical properties were also measured. The result showed that, the texture of the soils varied from loamy sand (sandstone) to sandy loam in shale and basalt. Electrical conductivity, organic matter, total nitrogen, available phosphorous and Ca, Mg, K were moderate. The results also revealed that sandstone soil with high sand content had higher release of P than the Shale and Basaltic Soil with high clay content. The trend was sandstone > shale > basalt. Parabolic diffusion equation successfully described the P release in the soils with the highest R2 values of 0.983.