Premium
Prolonged leaching of mineral forest soils with dilute HCl solutions: the solubility of Al and soil organic matter
Author(s) -
Dan Berggren,
Jan Mulder,
Roelof Westerhof
Publication year - 1998
Publication title -
european journal of soil science
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.244
H-Index - 111
eISSN - 1365-2389
pISSN - 1351-0754
DOI - 10.1046/j.1365-2389.1998.00150.x
Subject(s) - podzol , chemistry , leaching (pedology) , solubility , organic matter , soil water , pyrophosphate , environmental chemistry , lessivage , inorganic chemistry , geology , soil science , organic chemistry , enzyme
Long‐term acidification has been shown to result in a considerable decrease in the amount of organically bound soil Al and in a gradual decrease in the solubility of Al. We examined the solubility of soil organic matter (SOM) and Al in four acid mineral soils (one Arenosol Ah, two Podzol Bh, and one Podzol Bs) as they were leached sequentially using a solution containing 0.001 m HCl and 0.01 m KCl. The acid leaching resulted in relative decreases in Al that were 2–6 times greater than for organic C. The organic C and Al dissolved by the acid leaching originated mainly in the pyrophosphate‐extractable fraction of the elements. Protonation seems to be a major mechanism in stabilizing the residual SOM, as indicated by small changes in effective cation exchange capacity with the degree of acid leaching. In the samples of Podzol Bh and Arenosol Ah soils the solubility of Al (defined as log 10 {Al 3+ } + 1.5pH) in equilibrium suspensions (0.01 m KCl) was closely related to the ratio of pyrophosphate‐extractable Al to pyrophosphate‐extractable organic C. The Podzol Bs sample probably contained a small amount of a surface‐reactive Al(OH) 3 phase, which rapidly became depleted by the acid leaching.