Soils in southern China are in danger of being acidified due to the im
pact of long-term severe acid deposition. This paper presents the resu
lts of a batch experiment with five forest soils (two horizons from ea
ch) collected from five regions in southern China. The primary objecti
ve was to determine and compare the responses of these forest soils to
acid deposition. Each soil sample was extracted 15 times with deioniz
ed water or one of three acidic extractants made of dilute mixed acids
of H2SO4 and HNO3, and solutions of CaSO4, MgSO4 and NH4NO3. The tren
ds in ion concentrations and pH in the soil extracts, and the changes
in major soil properties such as pH, exchangeable base cations, exchan
geable aluminium, effective cation exchange capacity (CECeff) and base
saturation (BS) are discussed. In addition to exchangeable aluminium
(Al-ex), soil Al was extracted with CuCl2, pyrophosphate, and oxalate
solutions (Al-c, Al-p, and Al-ox, respectively). Considering both soil
and soil water, the results indicate that acid deposition has the lar
gest effects on the soils from Fujian and Nanchang, then followed by t
he soils from Hunan and Chongqing, while the effects on the Guiyang so
il are probably less serious. The release of aluminium (Al-rel, i.e.,
the total amounts in extracts) was highly correlated to soil water pH
and either of the aluminium pools, Al-p or Al-ox. For the aluminium mo
bilization (Al-mob, i.e., the sum of the aluminium release and the cha
nge in exchangeable aluminium) the best fit was obtained by using soil
pH and the Al-ox pool. Soil organic matter seemed to play an importan
t role in both aluminium release and aluminium mobilization. For two o
f the soils (Guiyang and Nanchang), the results were in excellent agre
ement with the values from previous column experiment with similar sol
utions. (C) 1998 Elsevier Science B.V. All rights reserved.