宁夏马家塘盐化土壤灌水前后盐分组成的分布

Characteristics about distribution of salt compositions in Ningxia Majiatang salinized soil after irrigation

为了改善宁夏马家塘新灌区灌水后土壤次生盐渍化现象,以马家塘灌区南部有盐化迹象的土壤为对象,选择两种不同土壤类型,即通体型盐化土壤和中位底盐型盐化土壤,在不同的灌水定额条件下,对土壤中可溶盐分组成进行分析.结果表明:该地区主要为硫酸盐型盐化土壤,土壤中SO42-占阴离子总量的96%以上,而对作物生长影响相对较大的Cl-含量较低,Cl-及其他阴离子含量总合所占比率不足4%;阳离子主要为Ca2+,占阳离子总量的90%以上,其他阳离子含量总合所占比率不足10%.通体型盐化土壤灌水后,在3600m3h/m 2灌水定额下,表层土壤SO42-和Ca2+含量较6000m 3h/m 2灌水定额下SO42-和Ca2+含量增加.因此,该类土壤的灌溉最好在灌区开发先期暂缓旱地改水田,并采取生物改良措施排盐.

To protect soil in new irrigation region in Majiatang south part of Majiatang, where sign of salinization of soil occurs from secondary salinization, an experiment area was selected in The study was carried out under different types of salinized soil and different quota of irrigation. Content of salt compositions in soil was determined before and after irrigation. The results showed that salinized soils were classified as sulfate and content of SO4 ^2- ion accounted for 96% of total anion content in great part soil but that of Cl^- ion, which is less harmful to plant, and other anion ions were less than 4%. Ca^2＋ ion is major cation in studied soil and took up 90% of total cation content. The contents of SO4 ^2- and Ca^2＋ ions in surface soil of the whole section salinized soil increased under irrigation quota 3 600 m^3/hm^2 than 6 000 m^3/hm^2. It is not suitable to change original soil into irrigated one in initial stage of irrigation region development.