根据研究结果认为，这种土壤的土体上部黄化是由于古红土中赤铁矿转化为针铁矿引起的。B层有棕化作用和粘化作用，应属棕壤类。
On the basis of present study it was suggested that the color tran - sition of red to yellow in the upper B horizon of the profile be due to the transformation of hematite to goethite .
粘化作用