Influence of Inorganic Salts on Concentration of Different Cd Forms in the Soil

Different soluble inorganic salts were irrigated into batches of soil samples by setting contrastive experiments on the basis of Tessier sequential extraction procedure to study their influences upon Cd forms in the soil. Research shows that all the three salts were able to influence the forms of Cd in the soil: NaCl and Na2SO4added into the soil could increase the contents of exchangeable Cd and the higher the concentration, the greater the impact, while Na2CO3could decrease it by 30.35%(4 g/kg Na2CO3added) and 69.87%(8 g/kg Na2CO3 added). Carbonate content of Cd was influenced obviously by NaCl, with the decrease of 7.30%, 10.52% corresponding to low concentration and high concentration of NaCl, and Na2CO3can increase this form slightly, Na2SO4had little effect, so the content remained unchanged. The Fe-Mn oxidation form of Cd remained the original level when NaCl was added in the samples while it increased with the addition of Na2CO3obviously and the concentration increased 8.67% (4 g/kg Na2CO3added) and 51.85% (8 g/kg Na2CO3added),but it decreased by the effect of Na2SO4. Organic Cd and the residual Cd fluctuated slightly at a very low concentration. The total Cd decreased with the addition of sodium salt.