干旱区绿洲灌溉条件对土壤盐分分布的影响

Effects of Irrigation Conditions on the Soil Salinization Distribution in the Oasis of Arid Area

干旱区绿洲土壤盐渍化现象普遍,不同灌溉条件下土壤盐基离子的季节分布、垂直分布各异,盐渍化是一个不断变化的动态过程。采用统计学方法,对新疆玛纳斯河流域不同灌溉条件下的夏秋两季土壤盐基离子进行了对比分析。研究结果表明：天然降水方式下土壤含盐量高于滴灌与漫灌方式,且各盐基离子季节差异最明显;滴灌在干旱区作物灌溉中意义重大,但压盐效果仍不及漫灌;滴灌和漫灌方式下全盐量在秋季呈现减少趋势,而天然降水方式下的土壤全盐量有所增加;各盐基离子中,季节变化最明显的有HCO-3,Na＋,K＋,其余离子在不同深度存在微量变化;不同深度土壤的盐渍化类型在漫灌方式下不稳定性要高于滴灌和天然降水方式下的土壤,且季节变动明显;流域内土壤的变异强度多为中等变异性,不同灌溉下各深度土壤全盐量的变异强度秋季大于夏季。流域内盐渍化现象普遍,pH值集中在7.9-8.7,建议建立合理的灌排体系,滴灌的同时要做好排盐压盐工作,防止区域土壤盐渍化的加剧。

Soil salinization is widespread in the arid areas.Salt ions under different irrigation distribution change with seasons and depths.Salinization is a dynamic process.Salt ions of soil under different irrigation conditions in summer and autumn in Manas River Basin were analyzed using statistical methods.The results show that the salinity under precipitation is higher than that under the drip irrigation and flooding irrigation.Salt is the most obvious in terms of the seasonal differences.Drip irrigation has great significance in the arid areas,but the effect on restraining salt movement is poor.In autumn,the contents of total salt decrease under drip irrigation and flooding irrigation,while the content of total salt increases under precipitation.Seasonal changes of HCO-3,Na＋and K＋are significant,and the changes of rest ions are not obvious.The salinization types in different depths are unstable due to the flooding,and its seasonal variation is more obvious.Most of the soil CVin this area is medium variation,and it is higher in autumn than summer.Alkaline soil is common in this area with pH ranging from 7.9to 8.7.It is advised to set up a reasonable irrigation and drainage system,and necessary to do something in soil desalt while drip irrigating so that to prevent the regional soil from salinization.