模拟酸雨对主要酸性土壤中铝的溶出及形态的影响

本文研究了模拟酸雨对主要酸性土壤中铝的溶出及形态变化的影响。结果表明,模拟酸雨对土壤酸化的影响较小,但对土壤铝的溶出却影响明显,尤其在pH<4.0时;模拟酸雨对不同类型土壤的影响是不同的,其中以高度风化的酸性土壤较为敏感。模拟酸雨对土壤游离铝形态的影响是重要的,酸处理后,交换性铝略有增加,无定形活性铝增加较多,而有机络合态铝有减少的趋势。这表明在酸雨的长期作用下,铝终将转化为交换性铝和水溶性铝而进入环境并危害生态系统。

Effects of simulated acid rain on release and forms of aluminum from main acidic soils.

The effects of simulated acid rain with different pH values on the amount of Al released and the change of Al forms of the main acidic soils in southern China were investigated. The experimental results indicated that acid rain had significant effects on the amount of Al dissolved from soils, especially in pH<4.0, but not on the acidification of soils. Acid rain had different effects in various soil types. Highly weathered acidic soils were more sensitive to acid rain. These were closely related to buffer capacity formed by different consumed mechanisms of H~+ and chemical characteristics of Al ions. It is very important that acid rain affected free Al forms of the soils. After acid rain treatment, exchangeable Al increased slightly and the content of moderately labile Al increased significantly. The trend in decrease of organic matter complexed Al was observed. Based on the results obtained in the present work, it was concluded that Al would be transformed to exchangeable or water soluble forms and entered the ecosystem by the effect of acid rain in the long-run. This is a serious problem.