关键词: 石膏, 苏打盐碱地, 土壤改良, 土壤理化性质

Abstract: In order to explore the effects of gypsum dosage on physical and chemical properties of soda alkali-saline soil under irrigation and drainage conditions, a laboratory simulation experiment was conducted to study the supernatant pH, supernatant ions, soil exchangeability ions, soil alkalinity, gypsum utilization rate under different dosage of gypsums (0, 0.6%, 1.2% and 2.4%). The results showed that the application of gypsum could significantly decrease pH and exchangeable sodium percentage (ESP) of soda alkali-saline soil, but increase the content of water-soluble salt ions in soil; irrigation and drainage could reduce the content of water-soluble salt ions and ESP of soil. After the application of gypsum, pH of upper liquid decreased firstly from 10.31 to 8.55～8.19, and then slowly increased over time. The soil pH values of 0.6%, 1.2% and 2.4% gypsum treatments were 9.53, 8.52 and 8.34, respectively, at the 5th day. The ESP decreased along with the irrigation and drainage. After 5 days, the ESPs of 0.6%, 1.2% and 2.4% gypsum treatments decreased to 50.40%, 33.00% and 25.23%, respectively. The utilization rates of gypsum were 52.59%, 58.1% and 40.99% under different dosage of gypsum treatments (0.6%, 1.2% and 2.4%). In consideration of the integrated soil improvement and gypsum utilization, the best dosage of gypsum was 1.2%.

Key words: gypsum, soda saline-alkaline land, soil improvement, physical and chemical properties of soil