Factors Influencing Diffusion of Phosphate in Some Soils of Himalayan Region

In a study on phosphate diffusion from ³²P labelled KH₂PO₄ in sixteen Himalayan mid-hill soils, it was found that the P diffusion coefficient (PBC) varied from 10.5xl0-⁸ to 68 85 x 10⁻⁸ cm²/sec with an average value of 24.63 x 10⁻⁸ cm²/sec. The soil factors that significantly influenced the diffusion coefficient in a bivariate correlation analysis were surface area, clay content, Al-P and free iron. In multiple regression analysis, the variation in PDC due to surface area, Al-P and free iron could be explained to the extent of 66.9% with 45.4% being the share of surf ace area alone. Thus, surface area, Al-P and free iron were found to be the important factors influencing phosphate diffusion in mid-hill soils of Himalayan region in north-west India, the first one being the most important among the three.