【摘要】 对鹤山赤红壤进行模拟酸雨野外淋溶实验的结果表明,供试土壤对pH≥3.0的处理具有较强的缓冲能力,淋滤液pH在全过程中可保持pH≈6.0。土壤系统对K+、Na+极强的净吸收作用导致二者淋失浓度在处理的中、后期为负值,显著低于Ca2+及Mg2+。在pH≥3.5处理下,土壤次级缓冲体系可使盐基离子总淋失浓度维持在一定水平。铝仅在pH≤3.0处理时溶出,在淋滤液pH≈4.5时溶出明显,可能的缓冲机制来自土壤对SO24-的吸附、次生矿物风化缓冲作用等。硅的淋失在pH≤3.5处理下差异不大,说明矿物风化缓冲机制在处理的全过程中都起了作用。鹤山赤红壤尚处在SO24-吸附阶段,对酸沉降仍有一定的缓冲能力。更多还原

【Abstract】 According to the field leaching experiment of lateritic red soil in Heshan using simulated acid rain（SAR）,when treated by SAR of pH≥3.0,the selected soil showed an effective buffering capacity with the overall pH values of soil leachates maintained at about 6.0.Due to a strong net-absorption in soil system,the concentrations of K⁺ and Na⁺ washed away were always negative values during the intermediate and later stage of the experiment,which were remarkably less than those of Ca²⁺ and Mg²⁺.When treated by SAR of pH≥3.5,the total concentrations of base cations washed away were maintained by the secondary buffering system of soil at a stable level.The leaching of Al³⁺ was observed only when treated by SAR of pH≤3.0 and,however,became obvious when the leachates’ pH values got close to 4.5,which might probably resulted from the buffering systems such as the absorption of SO^2-₄ by soil and the buffering of secondary minerals.The leaching concentrations of Si didnt vary too much when treated by SAR of pH≤3.5,indicating that the buffering system of mineral weathering functioned in the whole treatment.The lateritic red soil in Heshan is still in a stage of SO^2-₄ absorption,resulting in its buffering capacity of acid deposition to some degree.更多还原