Sammanfattning

The cation and SO, adsorption properties of O and B horizons of three podzolised soils in Sweden and Finland were studied through analysing the soil solution at six different sampling occasions and through a set of batch experiments. High concentrations of dissolved organic carbon and cations were found in centrifuged soil solutions from the O horizon, especially during autumn. An analysis using the WHAM-S model suggested that most of the dissolved Ca, Mg, K and Mn were counter-ions, residing in the diffuse layers of dissolved fulvic acids. Hence, the solubility of these cations depended on the solubility of organic matter. Model exercises suggested that the solubility of humics in turn was influenced by seasonal differences in hydrophobicity and by the water content. Furthermore, the model results showed that only a low proportion of the B horizon organic matter was involved in calcium binding. This is probably due to the interaction between organic matter and oxide surfaces in this horizon. In the case of sulphate adsorption in the B horizons, a surface complexation model was tested for its ability to describe batch experiment data and temporal differences in soil water chemistry. This model was based on the diffuse-layer model and it was optimised by adjusting the surface site concentration and the point of zero charge. However. the interaction between Ca2+ and SO42- could not be modelled. Comparisons between the model and the field observations proved to be difficult due to a considerable soil heterogeneity. (C) 2000 Elsevier Science B.V. All rights reserved.

Nyckelord

dissolved organic carbon; centrifugation; model; surface complexation; hydrophobicity

Publicerad i

Geoderma
2000, Volym: 94, nummer: 2-4, sidor: 311-333
Utgivare: ELSEVIER SCIENCE BV

SLU författare

• Karltun, Erik

  • Institutionen för skoglig marklära, Sveriges lantbruksuniversitet
    

UKÄ forskningsämne

Markvetenskap


Publikationens identifierare

DOI: https://doi.org/10.1016/S0016-7061(99)00038-5

Permanent länk till denna sida (URI)

https://res.slu.se/id/publ/69502