柳州地区酸沉降临界负荷的确定

为了对目标沉降量的制定提供定量依据，根据现场调查和实验测量获得柳州红壤的物理化学特性，地表水化学行性及降水化学背景和现状的数据，应用改进的ＭＡＧＩＣ模型计算不同酸沉降量下土壤的酸化过程。结果表明：柳州土壤已处于酸化状态并呈现继续酸化趋势，表层土壤敏感性较强，而底层土壤和地表水缓冲能力较强。

Assessment of Critical Loads for Acid Deposition in Liuzhou Area

In order to provide a quantitative evidence for establishing the target load, acidification processes of soils in Liuzhou area under different acid depositions levels were simulated using a revised MAGIC model on the basis of data about the physic-chemical properties of red earth, the surface water, and the background and present situation of precipitation, which were obtained by field investigations and experiments. The results showed that the soils in Liuzhou area have been already acidified and the acidification trend of the soils will become more serious with time. The upper soil layer is more sensitive to acid deposition while the bottom layer and surface water have larger buffer capacity. Critical loads of potential acidity for different red earth in this area are determined as 0.6-3.8 keq·ha^-1 ·a^-1, and that of sulfur deposition 0.7-3.2 g·m^-2·a^-1. In order to protect 95% of soil area from acidic deposition, sulfur deposition should be cut down by 70% of the present level at least.