红壤中铝的形态

以改进的连续分级提取方法，用１ｍｏｌ／Ｌ，ＫＣｌ，０．２ｍｏｌ／Ｌ，ＨＣｌ，０．１ｍｏｌ／Ｌ Ｎａ４Ｐ２Ｏ７（ｐＨ８．５），ＤＣＢ溶液，０．３３ｍｏｌ／Ｌ，柠檬酸钠和０．５ｍｏｌ／Ｌ ＮａＯＨ为提取剂，把红壤中可提取的非晶态铝区分为交换态铝，肿附态无机羟基铝，有机配合态铝，氧化铁结合态铝，层间铝和非晶态铝硅酸盐。

FORMS OF ALUMINUM IN RED SOILS

Extractable noncrystalline aluminum in red soils could be fractionated into exchangeable Al (ExAl), adsorbed inorganic hydroxy-Al (HyAl), organic complexed Al(OrAl), Fe oxide bound Al (DCBAl), interlayered Al (InAl) and noncrystalline aluminosilicate (NcAl), by the 1 mol/L KCl, 0.2mol/L HCl, 0.1 mol/L Na₄P₂O₇ (pH8.5), DCB solution, sodium citrate (0.33 mol/L, pH7.3) and 0.5 mol/L NaOH sequential extraction. All Al forms were characterized by the intrinsic feature in their composition and properties and closely related to the corresponding properties and ecological characteristics of red soils. In the same soil sample the amounts of various Al forms were of the order NcAl>InAl>DCBAl>OrAl>HyAl>ExAl. With the exception of ExAl content the contents of other five forms of aluminum in the red soils derived from basalt were higher than those from granite. In soils most of the aluminum existed in layer aluminosilicate minerals. Individual extraction of the Al forms in soils was compared with the sequential extraction method.