Availability Research of Rare Earth Element (REE) in Red Soils and Its Environmental Significance

Changes of chemical forms of REE in the profiles of red soils with different parent materials and changes of soluble REE contents show that availability degree of REE in red soils is higher than that in other soils, the mean total content of soluble REE accounts for 6%～7% of the total amounts of REE, and the main source of available REE is correlative to the adsorption of clay minerals and organic matter in red soils to REE.