Abstract: The salinization degree of soil in Bianwan farm, Jiuquan city, Gansu province, is so seriously that makes the agricultural production impossible. Therefore, the desulfuration gypsum was adopted to improve the soil samples from the tilling layer of Bianwan farm in order to evaluate its feasibility for improvement of saline-alkali soil. The results showed that, compared with the control group, the pH value, the degree of soil alkalization, total alkalinity and sodium adsorption ratio of the desulfurization gypsum treatment groups（11 250~45 000 kg/hm²） were significantly decreased, fell by 11.38% to 12.61%, 20.07% to 48.40%, 4.81% to 8.35%,and 8.35% to 22.92%, respectively; the content of Na⁺,Cl^-,K⁺ and Mg²⁺ decreased by 16.78% to 29.33%, 25.44% to 46.77%, 4.93% to 10.05%, and 6.61% to 17.72%, respectively, and that of Ca²⁺ and SO₄^2- increased by 12.91% to 43.46%, 5.77% to 40.77%. Thus, these phenomenons indicated an obvious decrease in salinity of the tested soil samples. So, the test scheme was good for the improvement of saline soil from Bianwan farm, and the optimal amount of desulfurization gypsum was 33 750 kg/hm².

Key words: saline-alkali soil, desulfuration gypsum, improvement effect, Bianwan farm