咸淡组合淋洗对土壤水盐分布特征的影响

为了缓解干旱半干旱地区淡水资源紧缺问题,最大限度地利用浅层地下微咸水,以全部淡水和全部咸水为对照,采用两咸一淡组合淋洗的方法对垂直土柱淋洗后土壤剖面的水、盐分布规律及土壤理化性质的变化进行研究,结果表明在累积入渗量相同的前提下,咸淡组合次序对土壤大孔隙的形成有影响,导致土壤透水性不同,通过入渗进入土壤的总盐量是土壤含盐量的主要影响因素;入渗历时的延长有助于提高土壤剖面脱盐深度,淡-咸-咸的组合次序洗盐效果最好;各种咸淡组合次序均导致20 cm深度处的钠吸附比较初始值增大,尤其是全部咸水入渗会降低土壤的渗透性,有可能导致土壤发生次生盐渍化.该研究为微咸水的田间合理利用提供了依据.

Effect of infiltrated by fresh and saline water alternately on water -salt distribution properties

In order to solve the problem of freshwater shortage, utilize water resource sustainably in arid and semiarid region, and make the best use of saline water in shallow ground water, saline-fresh water alternately continuous infiltration, contrast with all freshwater and all saline water, was taken to study the water-salt distribution in soil profile and soil physicochemical properties. It showed that, the alternate sequence affected the formation of the macropores and lead to the difference of water permeability of soil, the amount of salt which comes from irrigation water is the main factor of soil salt; the extension of irrigation time help to improve the desalting depth of soil profile, the infiltration sequence fresh-saline-saline is the best to salt-leaching effect; it makes the sodium adsorption ratio in 20 cm depth increase under each kind of fresh-saline water combination, the soil permeability will be decreased especially infiltrated all by saline water, it will probably lead to the soil secondary salinization, this study provides an basis to the reasonable utilization of saline water.