莱州湾海水入侵区地下水灌溉土壤水盐迁移特征分析

在用海水入侵区地下水大面积灌溉冬小麦试验的同时,进行了田间小区灌溉后的土壤水盐迁移特征的研究。结果表明:海侵区利用含盐量2.5~3.5 g/L的地下水进行4次灌溉,不仅加重了土壤含盐量,盐分离子组成及其化学性质也发生了变化。就砂壤土而言,雨季一次性降水20 mm以上或大暴雨后,表聚的土壤盐分迅速随雨水下渗或侧渗而排斥,不会因多次灌溉而聚集于土体;疏松表土层,切断毛管上升水通道,遇干旱高温季节,减弱水分的损失和土体盐分上升速度;土壤溶液化学性质中钠吸附比(SAR)值减少,而可溶性钠百分比(SSP)、钠钙镁比(SDR)值相应地增加,但没有因灌溉四次微咸水而引起土壤的次生盐渍化。

Analysis of salt and water movements in coastal saline soil in seawater intrusion region under groundwater irrigation

The characteristics of salt and water movements were studied in Laizhou Gulf region,where seawater intrusion became a severe problem in recent years.The results showed that,after irrigation for four times,salt content and ion composition in the soil changed greatly,but soil secondary salinization was not aroused.When happened with heavy rain(>20 mm), the total soluble salts at the root zone were rapidly leached down.Therefore,sodium absorption ratio(SAR) in soil solution was reduced,but on the contrary,soluble sodium percentage(SSP) and sodium-calcium-magnesium ratio(SDR) were increased.