干旱区生态环境知识资源中心

Soil salinity occurs usually in the arid, semi-arid and sub-humid irrigation region wherever evaporation is greater than precipitation, groundwater level high and groundwater containing more soluble salts. Soil salinity is one of the major problems that affect crop growth and yield and often lead to degradation of cultivated land. With more than 2000 years agricultural production and irrigation history, soluble salts accumulated in the irrigation region by extracting a large amount of Yellow River water year after year in Yinchuan Plain. Soil salinity risk is serious particularly in arid Yinchuan Plain, seriously hampering the region’s ecological environment and sustainable agricultural development. Therefore, it is needed to investigate the spatial distribution information of saline soil and analyse its influencing factors, so as to improve saline soil management condition. In this study, we used China-Brazil Earth Resources Satellite (CBERS)-02B image at a pixel resolution of 19.5 m to extract saline soil distribution map in April 2007 in Yinchuan Plain, and used CBERS-02B image to extract arable land distribution map August 2007. By Geographic Information System (GIS), the distribution information of saline soil information was obtained by overlaying saline soil distribution map and arable land map. The results show that the total area of arable land is 300,100 hm(2) with 41.75% of the total arable land area, non-saline arable land area of 125,300 hm(2), salt-affected amble land area of 174,800 hm(2) with 58.25% of the total arable land area. The slightly salt-affected arable land area is 67,500 hm(2), moderately salt-affected arable land area 58,700 hm(2), and heavily salt-affected arable land area 48,600 hm(2). We analyzed the underlying causes led to soil salinity including the high groundwater table, serious leakage of irrigation canals, insufficient irrigation and poor drainage, etc. We proposed the measures to control soil salinity in arid Yinchuan Plain.