酸沉降下加速土壤酸化的影响因素

The factors of influence accelerating soil acidification under acidic deposition

酸沉降对土壤和水域的酸化影响是土壤环境化学研究前沿的热点问题之一。酸沉降的化学组成对酸性土壤的进一步酸化起着催化剂的作用。在酸雨影响下,SO42-、NO-3、有机阴离子是加速土壤酸化和盐基淋溶损失的主要阴离子,外源H+的进入会加速铝离子水解。自然因素与人为因素导致土壤酸化的实际酸化速率差异表明:HCO3-、RCOO-在土壤剖面中的淋失状况可反映自然土壤的酸化速率,而SO42-和NO-3淋溶产生的质子负荷揭示土壤受人为因素影响的酸化速率。通过计算酸沉降的主要化学成分进入土壤前后的质子负荷平衡,与酸中和容量(ANC)相结合,反映酸沉降加速土壤酸化的进程。

The study on effects of acidic deposition on acidification of soils and water has long been one of frontiers in the research area of soil environmental chemistry .The chemical component of rainfall may be regarded as catalyst to further accelerate soil acidification. SO42-, NO3-and RCOO- are major anions to speed up soil acidification and leaching loss of base cation under acidic deposition and inputs of external H+ enhance dissolution of aluminium. Differences in rates of soil acidification caused by natural and anthropogenic sources of proton manifest that leaching of HCO3-, RCOO- reflects actual rate of soil acidification, whereas protons budget resulting from leaching of SO42-and NO-3 reveals rate of soil acidification affected by anthropogenic factors. Proton budgets produced by the major components of acidic deposition in soil, together with ANC, shows the process of soil acidification.