膜下滴灌农田灌溉量对土壤盐分类型的影响

摘要

To understand the change characteristic of soil salt and change mechanism of soil secondary salinity under the condition of cotton farm mulched drip irrigation in Xinjiang,a field experiment with 3 levels of irrigation amounts(3600 m3/ha,4200 m3/ha and 4800 m3/ha)was carried out to study the influence of irrigation amount of mulched drip irrigation on soil salt.Results showed that the content of total salt of soil decreased by 45.36 ％,57.94％ and 61.14％,respectively,with increasing irrigation amount.The types of negative and positive ions changed from Cl--SO42-and Mg2+-Na+ to SO42-and Na+,respectively,after irrigation,which made the main type of salt change from Na2SO4、NaCl、MgSO4、MgCl2 to Na2SO4.However,HCO3-and Na+were accumulated in soil with irrigation,which might result in soil secondary salinization or alkalization.%为弄清膜下滴灌农田土壤次生盐渍化迁移和转化特点,了解新疆滴灌农田土壤次生盐渍化演化机制,试验设置3个灌溉量水平(3600m3/hm2、4200m3/hm2和4800m3/hm2),研究灌溉量对土壤盐分类型及盐分运移的影响.结果表明,随着灌溉量增加,土壤总盐含量分别降低45.36％、57.94％、61.14％,灌溉起到洗盐作用.灌溉前、后土壤主要盐基阴离子类型由Cl--SO42-型转为SO42-型,阳离子由M2+-Na+型转为Na+型,土壤主要盐分由Na2SO4、NaC1、MgSO4、MgCl2转为Na2SO4.由于HCO3-在土壤中积累且灌溉水不断补充Na+,使NaHCO3含量增加,可能导致土壤苏打盐化或碱化.