脱硫石膏对重度苏打盐化土中主要离子淋洗的影响

Effect of Desulfurized Gypsum on Leaching of Major Ions in Heavy Soda Saline Soil

通过土柱室内淋洗的方法,研究土壤施加不同量(0g/kg,5.5g/kg,11g/kg,22g/kg,33g/kg)的脱硫石膏后,土壤淋洗液中4种盐基离子(Na^+、Ca^(2+)、CO_3^(2-)、SO_4^(2-))动态变化规律,旨在为大同苏打盐化土改良提供理论依据。结果表明,土壤淋洗液中Na^+淋洗量与时间呈显著负相关(P<0.05),CO_3^(2-)淋洗量与时间呈显著正相关(P<0.05),Ca^(2+)、SO_4^(2-)淋洗量在30d出现峰值,淋洗液pH与时间呈显著正相关(P<0.05),四大离子和pH随时间变化显示了苏打盐化土脱盐的过程。在5.5~22g/kg范围内,30d以前,随着土壤脱硫石膏用量逐渐增加,4种盐基离子的淋洗量均逐渐升高;30d以后,随着土壤脱硫石膏用量逐渐增加,4种盐基离子的淋洗量均逐渐降低。此外,和对照相比,施入脱硫石膏能提高苏打盐化土的导水能力。在试验范围内,22g/kg脱硫石膏用量的改良淋洗效果较好。

To provide scientific basis for the remediation of soda saline soil in Datong city,an indoor soil column experiment was conducted to study the dynamic variation of salt ions（Na＋,Ca^（2＋）,CO3^（2-）,and SO4^（2-））in leachate of soil under different dosages of desulfurized gypsum（0g/kg,5.5g/kg,11g/kg,22g/kg,and 33g/kg）.The results showed that the amount of Na＋in leachate had a significant negative correlation with leaching time（p〈0.05）,the amount of Ca^（2＋）and SO4^（2-）peaked on the 30 th day,and the pH and the amount of CO3^（2-）of leachate were positively correlated with leaching time（p〈0.05）.The temporal variations of the 4salt ions and the pH of leachate revealed the desalination process of soda saline soil.In the process of leaching,the 30 th day was a cut-off point.When the dosage of desulfurized gypsum was in the range of 5.5～22g/kg,with the increase of desulfurized gypsum application amount,the amounts of 4kinds of base ions in leachate increased in the first 30 days,and then gradually decreased after 30 days.In addition,the desulfurized gypsum could improve water-conducting capacity of soda saline soil compared with the control.According to the leaching effect of different dosage of desulfurized gypsum,22g/kg of desulfurized gypsum application was suggested in the study.