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选用了０．５ｍｏｌ／ＬＮＨ４Ｆ，０．２５ｍｏｌ／ＬＥＤＴＡ和０．２５ｍｏｌ／ＬＮａ２Ｃ２Ｏ４三种络合剂在不同ｐＨ条件下对红壤、赤红壤和砖红壤中的腐殖质进行了溶解比较试验．结果表明：各浸提剂对铝的浸提能力为ＮＨ４Ｆ＞ＥＤＴＡ和Ｎａ２Ｃ２Ｏ４（ｐＨ≤８），对铁的浸提能力则为ＥＤＴＡ＞Ｎａ２Ｃ２Ｏ４＞ＮＨ４Ｆ；各浸提剂在不同ｐＨ条件下，铁、铝及有机Ｃ（或Ｎ）的浸出量均为赤红壤＞砖红壤＞红壤。浸提剂的ｐＨ升高使有机Ｃ（或Ｎ）的浸提量增加，铁和铝的浸出量则不仅与络合剂对它的络合能力有关，而且还与溶液中ＯＨ－数量有较大关系。ｐＨ８左右的０．５ｍｏｌ／ＬＮＨ４Ｆ能较好地浸提出土壤中铝键结合腐殖质，且对铁键结合腐殖质破坏极小，它可能是一种区分土壤铁键结合和铝键结合腐殖质的较好溶剂。
Three kinds of complexing agents such as 0.5mol / LNH4F, 0.25mol / L LEDTA and 0.25mol / LNa2C2O4 were used to dissolve humus in red soil, lateritic red soil and lateritic red soil under different pH conditions. The results showed that the leaching ability of aluminum for each extract was NH4F> EDTA and Na2C2O4 (pH≤8), and the leaching ability of iron was EDTA> Na2C2O4> NH4F. Under different pH conditions, , Leaching amount of aluminum and organic C (or N) were red soil> brick red soil> red soil. The pH of the extractant increases the extraction of organic C (or N), and the amount of iron and aluminum leached is not only related to the complexing ability of the complexing agent but also to the amount of OH- in the solution Big relationship. 0.5mol / LNH4F at about pH8 could well extract aluminum-bonded humus in the soil and had minimal damage to the iron-bonded humus. It may be a better solvent for distinguishing iron-bound soil from aluminum-bonded humus .