金衢盆地的土壤铝状况及其对棉花生长的影响

Aluminium condition of the soils in Jin-qu Basin and its effect on cotton growth

选用浙江省金衢盆地８个具代表性和不同熟化程度的土样，研究了土壤的ｐＨ及不同浸提方法测得的铝含量与铝饱和度之间的关系，有机质对浸提铝含量的影响及土壤铝对棉花生长的影响。结果表明：不同方法浸提的铝含量和铝饱和度一般是随土壤ｐＨ的降低而增加，但重要原因之一还是有机质的影响，试验中，加柠檬酸可增加水浸提铝浓度，其增加值又随ｐＨ下降而增加。用不同方法浸提的土壤铝含量顺序不同。新垦、贫瘠的土壤上，铝对棉花生长的中毒影响与溶液中铝摩尔活度一致。生产上用０．０１ｍｏｌ·Ｌ￣（－１）ＣａＣｌ＿２的土壤浸提液铝浓度作棉花铝中毒的土壤诊断指标较好，临界浓度为０．１８ｍｇ·Ｌ￣（－１）。

Eight representative soil samples with different cultivation history in Jin-qu Basin of Zhejiang province were collected.The relationships between soil pH,extractable Al by different extraction methods and percent Al saturation of ECEC were studied.The effect of organic matter on extractable Al and the effect of soil Al condition on cotton growth were evaluated.The results showed that extractable Al and percent Al saturation of ECEC increased with decrease of soil pH,with some exception which might be attributed to the effect of organic matter.It was found that water extractable Al increased with the addition of citric acid,In the newly cultivated infertile soils the adverse effect of Al on cotton growth was consistant with Al activity in soil solution,It is sug-gested that 0.01 mol/L CaCl_2 extractable Al is the best diagnostic index of Al toxicity on cotton growth,critical Al concentration in solution is 0.18 mg/L.