COMPULSIVE EXCHANGE METHOD FOR DETERMINING SOIL EXCHANGE CAPACITIES -PROPOSED TIME AND LABOR SAVING MODIFICATIONS

Although the compulsive method for measuring the cation exchange prope rties of soils is being widely accepted particularly for highly we wea thered soils, part of the procedure is rather tedious involving the ad dition of water in a stepwise fashion to attain the specific conductan ce of a standard ionic strength which approximates that of many soil s olutions. A modification, which estimates this quantity of water by me asuring the specific conductance of the solution before addition of wa ter, is proposed. This estimate was based on calibrations conducted on thirty-one top- and sub-soils comprising examples from six soil order s. Results obtained by both the original and modified methods were com pared over 118 top- and sub-soils and were highly correlated (R2 = 0.9 9) with a slope of 1.02. The proposed modification is accurate as well as time and labor saving.