新疆铁干里克绿洲水文过程对土壤盐渍化的影响

在对塔里木河下游绿洲地表灌溉水和地下水水质特征及土壤盐分实测分析的基础上,探讨了地表水、地下水过程及其对土壤盐渍化的影响。结果显示：塔里木河下游绿洲灌区地表水矿化度与土壤表层0～50cm盐分含量呈显著正相关,与50～100cm土层含盐量相关性不显著;地下水埋深与土壤盐分含量密切相关,0～50cm表层土壤盐分含量随地下水埋深的增加而下降,其中0～20cm下降幅度最大。当地下水埋深较浅时,绿洲内土壤含盐量高,呈T型分布,盐分表聚性强,土壤盐分含量随土壤深度的增加呈下降趋势;当地下水埋深较深时,绿洲内土壤盐份呈菱形分布,中层土壤盐分高,且地下水矿化度和土壤盐分分布转折点均为6.0m。据此推断,6m是地下水盐分积聚和表层土壤盐分积累停止的临界地下水埋深。

Effect of Oasis Hydrological Processes on Soil Salinization of Tikanlik Oasis in the Lower Tarim River

Based on the monitoring data of soil salt content,quality of surface water and groundwater in the lower reaches of the Tarim River,the effect of hydrological processes of surface water and groundwater on soil salinization was analyzed.The results showed that there was evident positive correlation between degree of mineralization of surface water and salt content in 0-50 cm soil,but the relationship between degree of mineralization of surface water and salt content in 50-100 cm soil was not evident.Soil salt content was closely related to groundwater depth.And the salt content of 0.50 cm soil decreased with the increase of groundwater depth,especially 0-20 cm soil.The soil salt content was higher and showed a T-shaped distribution pattern when the groundwater depth was lower,but the highly aggregated salt content presented a decreasing trend with the increase of soil depth.On the contrary,the changes of soil salt content showed a diamond-shaped distribution pattern and soil salt content at intermediate layer was higher,when the groundwater depth was higher.The results also showed that the turning point of both groundwater mineralization and soil salt content distribution was 6.0 m.So 6.0 m was the critical groundwater depth to accelerate salt aggregation and stop accumulating soil salt content.