Ion enrichment of snowmelt water by processes within a podzolic soil

Ion concentrations in snowmelt runoff, forest-floor percolate and mineral-soil percolate collected in a tolerant hardwood forest at the Turkey Lakes Watershed, ON, were determined during the spring snowmelt of 1986. The results were examined to assess the modification of snowmelt water after contact with the forest soil. Concentrations of NO3- increased from 17 to 201 μmolc L-1 and SO42- increased from 25 to 107 μmolc L-1 as meltwater passed through the organic layers and the upper mineral-soil horizons. Mineralization of organic N and S, and desorption of So42- from the soil, provide sources of these ions for leaching during the snowmelt period. Ion-exchange reactions in the forest floor and upper mineral soil resulted in a decrease in H+ and an increase in Ca2+ concentration is solution. In the steep topography of this forested basin, the altered snowmelt solutions are rapidly transported downslope towards the aquatic system by lateral flow. Processes within the forest soil may therefore play an important role in determining the effects of snowmelt water on surface water chemistry in the spring