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Aluminium chemistry of the soil solution in an acid forest soil as influenced by percolation rate and soil structure
Author(s) -
FRANKEN G.,
PIJPERS M.,
MATZNER E.
Publication year - 1995
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 - 10.1111/j.1365-2389.1995.tb01357.x
Subject(s) - cambisol , chemistry , soil water , soil horizon , soil ph , soil science , horizon , environmental chemistry , geology , mathematics , geometry
Summary The predicted activity of Al in the soil solutions of acid forest soils often differs from that observed in the field. We have investigated the influence of soil structure and flow rate of the soil solution on the aluminum release to explain this divergence. Disturbed and undisturbed samples of soil were collected from the A and B horizons of a dystric cambisol at Waldstein (Fichtelgebirge, Germany). The samples were irrigated with solutions mixed according to field data on throughfall or soil solution composition with pH 3.5 with flow rates of 4 mm d −1 , 12 mm d −1 and 36 mm d −1 . The percolates were analysed for major ions. Resulting relations between pH and pAl were compared with batch experiments. In neither the A horizon nor in the B horizon did soil structure influence the relation between pH and pAl. The apparent equilibrium between pH and pAl was described as the pK app value with pK app = pAl— a pH (where a is an empirical constant). It was found that the pK app values for the column percolates were in the range of variation of those found in batch experiments. Flow rate had no influence on pK app at 4 and 12 mm d −1 . At 36 mm d −1 a significant increase of pK app was observed. This relative undersaturation of Al was more pronounced in the A horizon than in the B horizon. When flow is fast Al release into the percolating soil solution might be limited by diffusion.