酸沉降与我国南方森林土壤的酸化

Acid Deposition and Acidification of Forest Soils in Southern China

通过模拟酸沉降土壤连续浸泡试验,研究了我国南方5种森林土壤的酸化过程,并讨论了影响土壤酸化的几个因素。结果表明,土壤对酸沉降H+的中和能力,对酸沉降阴离子(SO2-4和NO-3)的吸附,土壤阳离子(Ca2+,Mg2+等盐基离子以及Al3+)的风化,土壤pH和BS的变化,都在土壤酸化过程中有着重要作用。同时,酸沉降的酸度(pH值)是决定土壤酸化的主要因素,而酸沉降中高含量的盐基离子可能缓解土壤的酸化过程。结合土壤本身物理化学基本特性可以得知,福建土壤对酸沉降引起的酸化最为敏感;江西、湖南土壤次之;重庆土壤的酸化敏感性较弱;而贵州土壤对酸沉降不太敏感。

Acidification of soil due to acid deposition in five forest regionsin Southern China was studied through a batch experiment by using simulated acid deposition, and several factors influencing soil acidification are also evaluated in this paper. The results showed that soil ability to neutralize H+ ions from acid deposition, adsorption of anions (<IMG SRC='IMAGE/05290005.JPG' HEIGHT=14 WIDTH=25><IMG SRC='IMAGE/05290006.JPG' HEIGHT=14 WIDTH=23> and ), weathering of soil cations (such as Ca2+, Mg2+, and Al3+), and changes in soil pH and base saturation, are closely related to the process of soil acidification. The acidity (or pH) of acid deposition, meanwhile, was a key factor to influence soil acidification, and high contents of base cations in acid deposition could alleviate this process. In combination of these factors and physicochemical characters of the soils, Fujiang soil is the most sensitive to acid deposition, followed by Jiangxi soil, Hunan soil, and Chongqing soil, and Guizhou soil is not very sensitive to acid deposition.