酸性土壤中活性铝的形态与铝毒

FORMS OF ACTIVE ALUMINUM IN ACID SOILS AND ALUMINUM PHYTOTOXICITY

对湖北省咸宁地区不同农业利用下，第四纪沉积物母质发育的１５个棕红壤土样，进行了小麦生长盆栽试验；离心法提取土壤溶液，并分别和连续用０．０２ｍｏｌ／ＬＣａＣｌ２，１ｍｏｌ／ＬＫＣｌ，ｐＨ４．８ＮＨ４Ａｃ和０．５ｍｏｌ／ＬＣｕＣｌ２溶液提取土壤铝。测定了小麦的生长参数、土壤溶液和几种提取液中的总铝量和快反应铝含量。结果表明，①Ａｌ３＋是土壤溶液中对小麦最具毒害的铝离子形态；②０．０２ｍｏｌ／ＬｃａＣｌ２和１ｍｏｌ／ＬＫＣｌ提取出的铝是对小麦产生毒害的主要活性铝；③１ｍｏｌ／ＬＫＣｌ提取的总铝量和快反应铝量能很好地反映土壤中毒性铝离子的含量；④１ｍｏｌ／ＬＫＣｌ连续提取的吸附态铝数量也在一定程度上决定着土壤铝对小麦的毒害作用；⑤ｐＨ４．８ＮＨ４Ａｃ，０．５ｍｏｌ／ＬＣｕＣｌ２等连续提取的铝主要是聚合态铝，对小麦生长没有直接的危害，但其数量大，且易转化，其作为潜在铝库的作用不容忽视。

Pot culture experiment with fifteen brown red soils derived from Quaternary Deposits and sampled from south Hubei Province were conducted in a short period(4 days)and longer term(30 days).The growth parameters of wheat seedlings and the content of different active aluminum forms were measured.Results indicated that Al3+ was the most toxic aluminum species in soil solutions.Aluminum extracted by 0.02 mol/L CaCl2 or 1mol/L KCl was mainly rapid reactive aluminum which was toxic to wheat growth.Total or rapid reactive aluminum extracted by 1mol/L KCl reflected well the content of toxic aluminum ions for acid soils.