Abstract
Soils carry positive and negative charges simultaneously but vary in space and time. Samples from the A and B horizons of a normal (Typic Calciargids having natric horizon) and a saline-sodic (Calcic Haplosolids) soils were collected. Positive and negative charges were determined by saturating the soils with IN KCl at soil-suspension pH 6, 8 and 10. The soils were extracted with 0.2 and 0.5N MgS04 .7Hp or Na2S04 solutions. Negative charges statistically increased with an increase in pH of both the soils. The increasing concentration of extracting solutions increased the negative charge, increase being more with MgS04 .7Hp than that with Na2 S04 • Response of positive charge to pH, concentration and nature of electrolytes was almost similar to that for negative charge for these soils. Negative charge was significantly higher in the A than that in the B horizon. An increase in pH or farm yard manure addition increased CEC and thus may decrease the rate of Ca-Na exchange, Le. soil sodication. Key words: horizon, charge, salinity, adsorption, dispersion
