Effects of Straw, Calcium Chloride, and Submergence on a Sodic Soil

The effects of straw and CaCl 2 during 130 days of submergence, and the effects of these amendments under submerged aerobic vs. anaerobic conditions for a period of 30 days were studied. Comparisons of pH, EC, Na, Ca + Mg, K, Fe, the optical density of the water extract, and ESP were used to evaluate the effects of these amendments. The straw and straw + CaCl 2 treatments had the largest effect in lowering the pH and the ESP, increasing the Na and Ca + Mg concentrations and the EC. Submerged anaerobic conditions had the largest effect on promoting these reactions. The concentration of Fe 2+ was highest in the straw treatments whereas CaCl 2 had a depressing effect on the soluble Fe 2+ . The optical density was lowest in the straw plus CaCl 2 amendment treated soil and the effect of this treatment was larger under anaerobic conditions. Wheat straw under anaerobic conditions caused an increase in the sum of Na plus Ca plus Mg that was about three times greater than the sum of these cations in the straw itself. In combination with CaCl 2 wheat straw reduced the loss of Ca from solution observed when CaCl 2 alone was added to soil.