The Relative Importance of ALuminum Solid-Phase OCMponent in Agricultural Soils Treated with Oxalic and Sulfuric ACIDS

摘要

Our ability to predict the toxic amount of labile aluminum in acidic soils is limited by our understanding hte interaction between different solid sources of aluminum in soils and soil solution pH. A soil acidification experiment, consisting of five consecutive equilibration of brown soils and peat soil with sulfurci and oxalic acid solutions was presented in this paper to determine the relative contribution of solid-phase aluminum to the labile aluminum in soil solutions. The distributio nof solid-phase aluminum pools in soils showed the predominance of organic-bound aluminum in all the studied soils, whereas the amounts of exchangeable and inorganic amorphous aluminum were relatively small. The reduction of the solid-phase aluminum pools by the simulated leaching with sulfuric or oxalic acids showed that organic-bound, amorphous, and free aluminum forms could act as aluminum sources. Organic-bound, amorphous, and free aluminum forms could act as aluminum sources. Organic-bound aluminum played the predominant role in soil acid neutralization. Generally, orgainc acid mobilized much more aluminum form mineral aluminum fraction, while inorganic acid prefer to act with organically bound aluminum fraction in mineral soil. Aluminum mobilization is a kinetic process.