SURFACE-AREA AND CEC AS RELATED TO QUALITATIVE AND QUANTITATIVE CHANGES OF FOREST SOIL ORGANIC-MATTER AFTER LIMING

Water vapor adsorption isotherms were used for estimation of (apparent ) surface areas of samples of limed and unlimed plots of an acidic san dy forest soil. Samples were taken at two microrelief (ridge and furro w) positions from five subsequent 10 cm layers. Values of surface area and CEC correlated linearly with organic matter content but only for four bottom layers. Surface areas and CEC values calculated per the un it mass of organic carbon were higher in upper layers than in lower la yers for control samples. For limed samples an opposite trend was obse rved. The estimated average (apparent) charge densities of organic mat ter showed a better correlation with humic to fulvic acids ratio. Valu es of surface charge densities for every investigated profile increase d with depth and they were lower in limed than in unlimed profiles.