微咸水灌溉条件下含黏土夹层土壤的水盐运移规律

黏土夹层影响着土壤水盐运移及分布,为了研究在含黏土夹层的土壤中进行微咸水灌溉时土壤的水盐运移规律,进行了春小麦微咸水灌溉大田试验,并在此基础上运用数值模型对土壤盐分累积趋势进行了模拟预测。结果表明,黏土夹层对土壤水盐运移具有显著的阻碍作用,黏土夹层以上土壤平均含水量、含盐量呈随灌溉水矿化度增大而增加的趋势,黏土夹层以下各处理土壤水盐分布几乎不受微咸水灌溉的影响;大定额冬溉洗盐后,各处理0～70 cm土层最大积盐率仍高达65.7%,部分盐分滞留在黏土夹层以上;土壤盐分分布预测结果表明,微咸水连续灌溉5 a后,灌溉水矿化度为4和5 g/L的处理土壤盐渍化倾向明显,不宜在含黏土夹层地区长期使用矿化度>3 g/L的微咸水进行灌溉,否则将对土壤环境产生严重危害。

Water and salt movement under saline water irrigation in soil with clay interlayer

The existence of clay interlayer in soils had impacts on water and salt movement and distribution.In order to study water and salt movement in soils with clay interlayer irrigated by saline water,the field experiment of saline water irrigation was conducted.A corresponding model was also used to forecast the cumulating trend of soil salt.The experiment results showed that when there was clay interlayer existed in the soil,soil water and salt could be hindered evidently.In upper soil layers(0-40 cm),the content of soil water and salt increased with increasing salinity.In bottom layers(80-120 cm),however,the content of soil water and salt had less relationship with salinity of water.The maximum rate of salt accumulation in 0-70 cm soil layers was 65.7% after leaching in winter and soil salt was partly detained in upper soil layers.The salinity prediction showed that there were soil salinization trends for 4 g/L and 5 g/L treatments after irrigating continuously for 5 years.Long term irrigation with saline water of the salinity higher than 3 g/L was not feasible in soil with clay interlayer and does serious harm to soil environment seriously.