Effects and Mechanism of Organic Acids on Aluminum Availability of Dark Brown Forest Soil

摘要

The effects and mechanism of different concentration organic acids and organic salts solution on Al availability of dark brown forest soil were studied.It was resulted that,oxalic acid/oxalate and citric acid/citrate substantially stimulated soil Al release of dark brown forest soil.The effect of organic acids/salts on Al release would be strengthen with increasing of their concentrations.The contents of Al released from A1 horizon was higher than that from B horizon.Organic salt solutions had much higher effects than organic acid the same in concentration,i.e.citrate＞citric acid,oxalate＞oxalic acid.Therefore,the mechanism of organic acid/salts triggering release of soil Al was assumed to be dominated by complexation reactions of organic anions.Citric acid/citrate had much higher effect than oxalic acid/oxalate at same concentration to A1 and B horizons,i.e.citrate＞ oxalate,citric acid＞oxalic acid,which was primarily related with the greater complexing capacities and dissociation constants of citric acid.