FLOCCULATION CONCENTRATION AND SODIUM CALCIUM EXCHANGE OF KAOLINITIC SOIL CLAYS

Clay dispersion in southeastern USA soils needs to be better characterized because dispersion influences crusting, infiltration, and erosion of field soils. In order to study dispersion of highly weathered soils, clays separated from Ap and Bt horizons of three soil series from the Georgia Piedmont were equilibrated with solutions of varying sodium adsorption ratio (SAR) and ph in order to determine the effects of these parameters on the electrolyte concentration necessary for clay flocculation. These results confirm field observations of dispersion-related crusting and permeability decreases on these soils under rainfall, and suggest the importance of maintaining low Na contents, moderate pH levels, and high solution ionic strengths. -from Authors