再生水灌溉对土壤主要盐分离子的分布特征及盐碱化的影响

通过田间试验,研究再生水纯灌、轮灌、重要时期灌清水等不同灌溉策略对西红柿和黄瓜地块土壤主要盐分离子的分布特征及盐碱化的影响。结果表明:对于西红柿地块,除Cl-和HCO3-在表土中的发生积累外,其他主要盐分离子均强烈受到灌溉水淋溶作用的影响,表现出向土壤深层迁移的特征,但是再生水灌溉未引起土壤剖面盐分的累积。对于黄瓜地块,土壤盐分分布对不同再生水灌溉策略的响应不同于西红柿地块,强烈的蒸发作用造成了主要盐分离子(除HCO3-外)在土壤表层中出现积累,但是未监测到盐分在深层土壤中累积。再生水灌溉对西红柿和黄瓜地块土壤的pH值和SAR值均未产生显著影响,但是较高的pH值(>8.0)说明长期灌溉再生水可能引起土壤的碱化。研究认为重要时期灌清水处理在控制土壤盐分累积方面效果明显,且未引起土壤发生碱化,可作为短期再生水灌溉果蔬菜(西红柿、黄瓜)的有益尝试。

Effects of Treated Wastewater Irrigation Strategies on the Distribution of Salt Contents in Soils Cultivated with Tomato and Cucumber

A field experiment was designed to evaluate the effects of treated wastewater irrigation strategies on the distribution of salt contents in soils cultivated with tomato and cucumber.For tomato plots,irrigation with treated wastewater only increased the contents of Cl-and HCO-3 in the surface horizon of soil(0-10 cm),other salt ions were leached to the deeper soil profile due to irrigation.The salt concentration in the whole soil profile was not significantly cumulative under different treated wastewater irrigation strategies.In the plots cultivating with cucumber,all the salt ions exclude HCO-3 increased in the surface of soil due to intense evaporation in the greenhouse.However,no obvious risk was measured for the salinization of soil ir-rigated with different treatments.Furthermore,after harvest,soil pH and SAR was not remarkablely affected by treated wastewater irrigation compared with freshwater,but the risk of soil alkalization still needed to be a concern due to the relatively high pH(>8.0).In conclusion,among all treatments,irrigation with freshwater in the important period(FWF) during the growth stage is an alternative strategy for regulating soil salinization and alkalization in the safe utilization of treated wastewater.