Solid components and acid buffering capacity of soils in South China

The effects of soil solid components on soil sensitivityto acid deposition were studied in this paper by sequentialextraction method. A multiple regression equation of soilsensitivity was set up on the basis of stepwise regressionanalysis. The results showed that organic matter expressed dualeffects that were decided by soil original pH value andexchangeable cation composition on acid buffering reactions. Thehydrolysis of activated oxides was a very important protonbuffering reaction when in low pH situation. The crystalline oxidesalso played a role in the buffering reactions, but the role wasrestricted by the rate of activation of oxides. Meanwhile, theresults by stepwise analysis showed that factors that hadsignificant effect on soil acid buffering capacity were content ofmontmorillite, soil original pH value, Alo, Mno and CEC indecreasing order. Finally, sixteen soils were classified into fourtypes of sensitive with single index cluster and multiple fuzzy cluster analysis respectively.