Study on release of zinc from red soils under the influence by simulated acid rain

A soil leaching column experiment was designed to investigate the release of zinc from red soils under the influence by simulated acid rain. After 9 150-10 650 mm precipitation leaching, compared with pH5. 6 precipitation, pH4. 5 acid rain made the pH of surface layer soils decline 0. 15-0. 22 units, but had no obvious influence on the pH of center layer and bottom layer soils; pH3.5 acid rain made the pH of entire soil layer some extent decline, especially obvious in surface layer, the pH declined 0.43-0. 60 units. Under the influence by simulated acid rain, there is a two - phase - characteristic of speedy descending release at early stage and slow reposeful release at latter stage. The cumulative release of zinc can be described with quadratic model. On the point of long-term leaching, acid rain can lead the loss of zinc of red soils. This impact of acid rain on release of zinc heightens zinc load in the water, leads soil lacking zinc, and aggravates poison of soils polluted by zinc. 3figs. , 3tabs. , 8refs.