A STUDY OF FOREST SOILS AND LEACHATES ON SLOPING TOPOGRAPHY USING A TENSION LYSIMETER

Abstract

Acrylic tension lysimeters were used to collect both vertically and horizontally moving water from soils at two different forest sites on sloping topography. The leachates were analyzed for ion content and the values compared within each soil, between soils, and relative to soil properties. The topographically lower site (Whatcom soil) had an accumulative leachate volume collected over the 4-month study period of 2387.4 liters, whereas the upper slope soil (Blaney series) yielded only 901.2 liters of leachate. Collected leachate volumes varied within each pedon as expressed by the Whatcom soil values of 22.8 liters from the surface soil horizons increasing to 1184.0 liters from the horizons immediately above the impervious glacial material. Downslope movement of water occurred throughout each pedon but to a greater extent in the subsurface horizons. Although more leachate was collected from the Whatcom soil, the ionic concentrations were similar between the two sites. Within the pedons the podzol B horizons had the highest ion concentrations. The general order of cation abundance was [Formula: see text], which was explained by the mineralogical composition of the soils. The anions varied in their abundance but bicarbonate was generally the most abundant. Seasonal trends were indicated in both anion and cation leachate concentrations. The volume of leachate collected and the similarity of ion concentrations between the two sites added support to previous studies relating forest site quality to soil parameters.