Abstract
The distribution of acid buffering patterns in the infiltration process was investigated in the soil layers of a temperate forested catchment focusing on their spatial variations. The investigation consisted of catchment-scale hydrochemical observations and in-situ lysimeter experiments done on the surface layer of soil. The spatial variation of the ion components of soil water, and groundwater, observed for each hydrological elementary process in the measured catchment, showed the existence of two spatially different types of acid buffering mechanisms distributed in the infiltration processes. In the top soil layer, which is affected by the nutrient cycle between plants and soil, the buffering was characterized by the reaction of the biologically supplied protons with organic acid and NO3-, in addition to the input by throughfall, being exchanged by Ca2+ and Mg2+ at cation exchange sites. In the lower layer, it was clarified that a dominant role is played by the buffering mechanism where by protons, produced mainly by dissolution and dissociation of soil CO2 gas, are consumed in the process of chemical weathering. It is emphasized that the lower soil layer plays as an important role in evaluating the buffering potential of the scale of catchment.
