Geoscience Reference
In-Depth Information
Fig. 18.29 Pathways of soil solution sulfate concentration with and without adsorption
following deposition increase, and showing a variety of sulfate reversibility responses following
deposition decreases (Harrison et al.
1989
). Copyright 1989 American Society of Agronomy.
Reprinted with permission
Fig. 18.30 Irreversibly
adsorbed SO
4
2-
versus total
SO
4
2-
adsorption from
0.25 mM CaSO
4
solution for
soils (Harrison et al.
1989
).
Copyright 1989 American
Society of Agronomy.
Reprinted with permission
been studied in Dutch field conditions (van Bremen et al.
1984
; Mulder et al.
1987
,
1989
). In these cases, it was observed that aluminum fractions are leached from
acidic sandy soils, inducing depletion of certain aluminum fractions within several
decades. Organic aluminum, for example, is removed from the surface layer at a
rate of 1-2 % per year.
Aluminum is transferred to solution mainly from the organically complexed
solid phase. Mulder et al. (
1989
) showed that depletion of alumino-organics in
podzols was most pronounced in the upper layer of the soil profile, and that as a
consequence, acid rain input produced a drastic change in the naturally occurring
