摘要
在奇台县绿洲中部平原区和绿洲沙漠交错带选择不同耕种时间的农田,分析其剖面土壤可溶性总盐、pH值含量随耕种时间的变化。探讨在地下水埋深不断下降的过程中,不同发展阶段农田土壤盐渍化的时空变化规律。研究表明:奇台县绿洲地下水埋深已低于影响地表盐渍化的地下水埋深临界值(5m),地下水矿化度低于3g/L,研究区整体处于有利于土壤盐渍化逆向演替的环境。土壤含盐量与地下水埋深关系最为密切,地下水埋深在3-5m时,土壤脱盐速度最快,大于5m时,含盐量减少的速率明显降低。土壤盐渍化逆向演替具有时空特征。时间特征表现在,无论农田在绿洲的什么位置,耕种时间越长,土壤含盐量越低,盐渍化逆向发展的越好。当农田耕种时间和地下水埋深低于临界值的时间超过20年时,盐渍土基本可以自然恢复为非盐渍土。空间特征表现在,由绿洲下部向上部,土壤盐渍化逆向演替阶段逐渐向高级过渡。
Choosing farmlands of different cultivated time in plain and oasis - desert ecotone in Qitai oasis to analyze the movement of soil soluble total salt and pH value. With the decline of groundwater table, the temporal and spatial changes of farmlands soil - salinization in different phases were discussed. The results showed that Qitai oasis has already in a circumstance which is valuable for soil - salinization reversal evolvement. Groundwater table is below 5 meters, the critical point could affect the surface salt accumulation. Groundwater mineralization degree is lower than 3g/L. The relation between soil salt content and groundwater table is close. When groundwater table is 3 to 5 meters, the speed of desalinization is the fastest. While groundwater table lower than 5 meters, the speed of desalinization slow down obviously. Salinization reversal evolvement presents temporal and spatial characters. From the aspect of time, no matter in what physiognomy positions of oasis, the longer the cultivated time last, the less the salinity become, the better the salinization reversal evolvement develop. When the time of farmlands cultivating and the time of groundwater table under 5 meters last more than 20 years, saline soil can convert into non - saline soil. In point of space, from the lower to the upside of Qitai oasis, the stage of soil salinization reversal evolvement gradually transfers to high -level.
出处
《干旱区资源与环境》
CSSCI
CSCD
北大核心
2009年第7期168-175,共8页
Journal of Arid Land Resources and Environment
基金
国家自然科学基金(40771194)项目资助
关键词
土壤盐渍化
逆向演替
奇台县绿洲
soil - salinization
reversal evolvement
Qitai oasis
