伊犁河流域土壤盐渍化对地下水特征的响应

The Response of Soil Salinization to Characters of Groundwater in Ili River Basin

分析土壤盐渍化与地下水特征之间的关系对区域水土资源可持续利用具有重要意义，同时也为地下水资源管理的科学化和现代化提供技术支撑。利用136个土壤剖面的540个土壤样品及相应地下水观测数据，采用对数正态分布模型，对伊犁河流域地下水埋深、矿化度对土壤盐渍化的影响进行了研究．计算分析了防止土壤盐渍化的地下水临界深度。结果表明：研究区表层土壤含盐量随地下水矿化度的增加呈指数增加的趋势：各土层含盐量随地下水埋深的增加呈对数下降的趋势；当地下水矿化度介于1-3g／L、3-6g／L、6-10g／L与1-10g／L时，盐渍化土壤出现频率峰值所对应的地下水埋深分别为1．44m、1．65m、1．83m与1．63m。为了防止土壤次生盐渍化，当地下水矿化度介于1-3g／L、3-6g／L、6-10g／L与1～10g／L时．地下水埋深分别控制在2．06m、2．49m、2．66m与2．24m以上。地下水矿化度越大，可在较大的地下水埋深范围内发生土壤盐渍化。对数正态分布模型分析结果与对数拟合曲线分析结果基本一致，说明研究结果是可靠的。地下水埋深2．5m可作为防止土壤盐渍化的临界地下水埋深。

Study on the relation between soil salinization and characteristics of groundwater is significant for sustainable use of soil, water resources, and providing technical supports for scientific management of groundwater resources. Based on the observed data of 540 soil and groundwater samples from 136 sampling points, using logarithmic normal distribution model, the effects of groundwater depth and salinity on soil salinization in the Ili River Basin was analyzed, and the critical depth of groundwater for soil salinization control was studied. The resuhs indicated that the salinity of surface soil layer is exponentially increased with the increase of groundwater salinity, and salinity of each soil layer is logarithmically decreased with the increase of groundwater depth; While groundwater salinities are within 1-3g/L, 3-6g/L, 6-10g/L and 1 - 10g/L, the maximum frequency values of groundwater depth for salinized soils are 1.44m, 1.65m, 1.83m and 1.63m, respectively. Therefore, groundwater depth should be more than 2.06m, 2.49m, 2.66m and 2.24m for control of soil salinization while the groundwater salinities are 1 - 3g/L, 3-6g/L, 6 -10g/L and 1 -10g/L, respectively. Soil salinization could happen in a larger groundwater depth with the increase of groundwater salinity. The results of logarithmic normal distribution model and logarithmic fitting curve were obviously consistent, explained the reliability of results of the study. It indicated that 2.5m could be the critical groundwater depth for control of soil salinization.