Effects of simulated acid rain on leaching of phosphorus, Ca2+, Al3+ and Fe2+ from lateritic red soils

A soil column method was applied to study influences of simulated acid rain (SAR) on leaching characteristics of dissolved phosphorus (DP), Ca2+, Al3+ and Fe2+ in lateritic red soils in south China. The results revealed that compared to the control, the change of leaching pH was not so obvious (＞0.05), but large amounts of leaching losses of Ca2+, Al3+ and Fe2+ were caused by SAR, and the amounts of Ca2+, Al3+ and Fe2+ were all increased with the decrease of SAR pH. The amounts of Al3+ and Fe2+ were increased dramatically when the pH of SAR is 2.0. While as the time elapses, the amount of leaching phosphorus was increased at first and then decreased slowly, and the total amount of leaching phosphorus also had the same trend when the pH of SAR was decreased. The amount of water soluble P leaching was increased when pH was larger than 4.0 and was decreased when pH was less than 4.0. The results of correlation analysis showed that the amounts of Al3+ and Fe2+ had dramatically negative correlation with the leaching phosphorus (r1=-0.6531，r2=-0.5107). The more the acid rain releases active iron and aluminum, the more active phosphorus adsorption and fixation of soils.