Simulation of the effect of acid-rain on soil acidity in litchi orchard plantation

Through limited indoor leaching,the effect of acid-rain on soil acidity under litchi orchard was studied,and selection criteria of appropriate soil acidification discussed in the context of the factors of soil acidity.The study shows that,using pH(H2O) as an acidification index,acid-rain with pH4.5 leads to soil acidification,whereas acid-rain with pH ≥ 5.5 has a buffering effect on soil acidification;Using soil pH(KCl),exchangeable acidity(EA),exchangeable aluminum(EAl) or titratable acidity(BNC) as acidification indices,acid-rain with pH 2.5 leads to soil acidification,but soil acidity decreases after leaching of acid-rain with pH≥3.5.