Trends in soil fractal parameters caused by accumulation of soil organic matter as resulting from the analysis of water vapor adsorption isotherms

The experimental adsorption isotherms are used to evaluate the specific surface area and the surface fractal dimensions of several samples containing organic matter. The aim of the investigations has been to search for correlations between specific surface area and geometrical heterogeneity, as characterized by the surface fractal dimension and the content of organic matter. Besides natural organic soils (peats, forest humuses and brown coal from mines) we also investigate controlled systems obtained by adding humic acids to kaolin and quartz, organic compost to soils and by mixing sandy soil and peat at different ratios. The aim of the investigations of controlled systems was to discover some general trends in the dependencies of the specific surface area and the surface fractal dimension on the content of organic matter.