新疆渭干河流域土壤盐渍化时空变化及成因分析

以1985 年渭干河流域土壤普查数据、1998 年Landsat TM影像和2008 年CBERS影像为数据源, 通过人机交互解译方式获取3 个时期土壤盐渍化分布状况, 然后采用GIS空间分析方法对23 年来土壤盐渍化时空变化特征进行分析。结果表明:①1985-2008 年, 总趋势是随着流域灌区和耕地面积的扩大, 盐渍化耕地也随之增加, 土壤盐渍化耕地面积由13.32×10⁴hm²增至13.78×10⁴hm²。②流域土壤盐渍化现象普遍, 主要分布在绿洲的下部边缘地带, 河流中下游、地势平缓低洼等区域, 盐渍化耕地在绿洲内部呈条形状分布, 在绿洲外围呈片状分布。③河道、渠系和水库渗漏、耕作制度不合理、土地不平整和气候变化等多种因素导致渭干河流域土壤盐渍化扩大, 但在局部地区由于生态恢复和改良利用措施, 使得土壤盐渍化面积也有缩减。

Causes and Spatial-Temporal Changes of Soil Salinization in Weigan River Basin, Xinjiang

Based on the soil data of the year 1985,Landsat TM images of 1998 and CBERS images of 2008,we reconstructed three-period distribution of soil salinization through interactive machine-artificial interpretation.Then the spatial-temporal changes over the past 23 years were analyzed with the support of GIS spatial analysis methods.The results are shown as follows.(1) With the expansion of arable land,salinization of arable land increased,too.Soil salinization land increased from 13.32×104 hm2 to 13.78×104hm2.(2) Soil salinization is widespread,mainly in the lower edge of the oasis,the river downstream and the low-lying flat terrain areas.Salinized arable land presents a bar-shape distribution inside the oasis and a patch-shape distribution outside the oasis.(3) The expansion of soil salinization of Weigan River Basin was primarily caused by factors such as the increasingly drier climatic changing trend,river,canal and reservoir leakage,irrational farming,and the fact that the land is not flat.However,it has been alleviated by the implementation of ecological restoration and amendment of reclamation.