Effects of simulated acid rain on the release of Al~(3+) in typical soils from Three Gorges Reservoir region

The releasing pattern of Al3+ in different horizons in four types of typical soils,which samples were collected from the Three Gorges Reservoir Region,is studied by simulated acid rain leaching of soil columns equipment indoor.The results indicate that the buffering capacity of the tested soils against acid rain is weakened after a long time of leaching,and acid rain of a lower pH presents a stronger impact on the acidification of the soil.The leaching amount of Al3+ in four types of typical soils increases with the decline of acid rain pH value.The leaching quantities are low while the pH value is equal or greater than 3.50 levels,but increase remarkably while the pH is 2.50.Meantime,leaching of simulated acid rain changes the concentration of exchangeable Al3+ in soil (except for red-brown purplish soil).These changes are more remarkable in soils with the pH decrease of simulated acid rain.