有机酸对森林土壤pH及铝形态变化的影响

采用连续提取法研究低分子量有机酸对南方酸性森林土壤pH及铝形态变化的影响.结果表明,在酸性土壤上,有机酸处理后土壤pH降低,土壤可溶性铝和有机络合态铝增加,交换态铝(Al3+)、单聚体羟基铝Al(OH)2+、Al(OH)2+]和酸溶无机铝Al(OH)3]减少,土壤中不同形态的铝都有向有机络合态铝转化的趋势,这种转化降低了土壤活性铝的含量,有利于减轻土壤铝对植物的危害,但不同的有机酸由于其性质和结构不同,对土壤铝形态转化的影响不同.土壤中各形态铝含量上层土壤大于下层土壤.

Effects of low molecular weight organic acids on the pH and the form of aluminum of forest soils

Effects of organic acids on the pH and aluminum forms in acid forest soils of southern China were studied using sequential extraction method. Results revealed that after dealt with organic acids, soil pH decreased, soluble aluminum and organic complex aluminum increased, exchangeable aluminum (Al~\{3+\}), Al(OH)~\{2+\},Al(OH)_2~+ and Al(OH)_3 decreased. Other forms of aluminum inclined to transform to organic complex aluminum. This will reduce the content of active aluminum in the soil and may reduce the aluminum toxicity to plants. Because of the different characteristics of organic acids, they have different effects on the forms of aluminum in the soil. The content of all forms of aluminum in the upper layer of soil is greater than that in the lower layer.