Soil solutions were taken from untreated and lime treated Norway spruce sites in the south of Sweden. At the limed sites
3.45 t ha1 (L) or 8.75 t ha1 (H) dolomite were applied 15 years before sampling.
The mean concentration of inorganic Al (AlQR) in the untreated control plots (C) was 37 AM and the concentration of
AlQR decreased when the dosages of dolomite treatments increased. For the H plots, with high doses of dolomite
treatment the mean concentration of AlQR was 17 AM. The total Al (Altot) also decreased by dolomite treatment, from 72
AM to 56 AM.
Propionate (7–268 AM) and malonate (2–34 AM) were the low molecular weight organic acids (LMWOAs) found in the
highest concentrations at Hasslfv. The differences in concentration of most of the determined LMWOAs were significantly
increased due to treatment. The citrate average concentration for the different plots varied between 2.8 AM and 5.1 AM and the
concentration of oxalate had concentrations between 1.7 AM and 2.6 AM. The experimental concentration of Al bound to
LMWOAs obtained by ultrafiltration (b1000 Da) of the soil solution was in the mor layer on average 12% for the C plot and the
L plots and 4% in the H plots. In the AE horizon the figures were 15% for the C plot and about 7% for the treated L and H plots,
and in the Bhs horizon 9% for both the C, L and H plots.
Two chemical equilibrium models were evaluated: Winderemere Humic Aqueous Model (WHAM) and a model treating
the high molecular weight organic acids as monoprotic. The concentrations of inorganic Al, Al bound to identified
LMWOAs and high molecular weights acids in soil solution (mor, AE and Bhs) from untreated and lime treated soil were
calculated.
The modelled inorganic Al values of the control plot were similar to the concentrations found in the soil solution (AlQR). For
the dolomite treated plots the concentration of AlQR (0–40 AM) was higher in soil solution than that modelled by WHAM and
the monoprotic model.
The experimental concentration of Al bound to LMWOAs obtained by ultrafiltration (b1000 Da) of the soil solution was
comparable but always higher than the modelled values. The modelling confirms that an appreciable part of the Al is strongly
complexed with LMWOAs in the organic and eluvial horizons of the podzolized soil, suggesting that LMWOAs are efficient
weathering agents and important for the formation of the eluvial horizon in podzols.
Soil solutions were taken from untreated and lime treated Norway spruce sites in the south of Sweden. At the limed sites
3.45 t ha1 (L) or 8.75 t ha1 (H) dolomite were applied 15 years before sampling.
The mean concentration of inorganic Al (AlQR) in the untreated control plots (C) was 37 AM and the concentration of
AlQR decreased when the dosages of dolomite treatments increased. For the H plots, with high doses of dolomite
treatment the mean concentration of AlQR was 17 AM. The total Al (Altot) also decreased by dolomite treatment, from 72
AM to 56 AM.
Propionate (7–268 AM) and malonate (2–34 AM) were the low molecular weight organic acids (LMWOAs) found in the
highest concentrations at Hasslfv. The differences in concentration of most of the determined LMWOAs were significantly
increased due to treatment. The citrate average concentration for the different plots varied between 2.8 AM and 5.1 AM and the
concentration of oxalate had concentrations between 1.7 AM and 2.6 AM. The experimental concentration of Al bound to
LMWOAs obtained by ultrafiltration (b1000 Da) of the soil solution was in the mor layer on average 12% for the C plot and the
L plots and 4% in the H plots. In the AE horizon the figures were 15% for the C plot and about 7% for the treated L and H plots,
and in the Bhs horizon 9% for both the C, L and H plots.
Two chemical equilibrium models were evaluated: Winderemere Humic Aqueous Model (WHAM) and a model treating
the high molecular weight organic acids as monoprotic. The concentrations of inorganic Al, Al bound to identified
LMWOAs and high molecular weights acids in soil solution (mor, AE and Bhs) from untreated and lime treated soil were
calculated.
The modelled inorganic Al values of the control plot were similar to the concentrations found in the soil solution (AlQR). For
the dolomite treated plots the concentration of AlQR (0–40 AM) was higher in soil solution than that modelled by WHAM and
the monoprotic model.
The experimental concentration of Al bound to LMWOAs obtained by ultrafiltration (b1000 Da) of the soil solution was
comparable but always higher than the modelled values. The modelling confirms that an appreciable part of the Al is strongly
complexed with LMWOAs in the organic and eluvial horizons of the podzolized soil, suggesting that LMWOAs are efficient
weathering agents and important for the formation of the eluvial horizon in podzols.
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