PHOSPHORUS TRANSFORMATIONS IN A SOIL CHRONOSEQUENCE, VANCOUVER ISLAND, BRITISH COLUMBIA

Phosphorus fractionation and analyses for free oxides of Fe, Al and Si were carried out on depth interval samples taken from a sandy soil chronosequence on the west coast of Vancouver Island, British Columbia. The seven profiles sampled ranged in age from 127 yr at Site 1 to 550 yr at Site 7. Calcium-bound phosphate (P_Ca) decreased in the 0- to 5-cm depth interval samples from 105 mg kg⁻¹ at Site 1 to 2 mg kg⁻¹ at Site 7 and similar but less-pronounced decreases were noted for lower depths. Profile averages of P_Ca exhibited a linear function with time, whereas exponential trends were noted for the surface 10-cm samples. Key words: Phosphorus fractionation, soil chronosequence, chronofunctions, soil phosphorus