Phosphorus sorption properties in podzolic forest soils and soil solution phosphorus concentration in undisturbed and disturbed soil profiles

Podzol horizons (O, E, B1, B2 and C) from three undisturbed sites were analyzed for phosphorus (P) sorption, P saturation, P fractions, and P concentrations in soil solutions, and three disturbed Podzols for P in soil solution.The threshold concentrations for net sorption were 8000 µg l -1 and 700 µg l -1 for the O and E horizons, respectively, and 3-6 µg l -1 for the B1, B2 and C horizons.Consequently, if water percolates through the B horizon the risk of P leaching is low.Phosphorus saturation degree was 0.2%-25%.Fe-P dominated in the O, E, B1 and B2 horizons, and Ca-P in the C horizon.P was depleted from the E horizon (24 µg g -1 ) and enriched in the B1 and B2 horizons (500 and 250 µg g -1 ) as compared with that in the C horizon (160 µg g -1 ).P in soil solution increased in the topmost 3 cm of the disturbed B horizons.