Variation of groundwater salinity and its influence on crops in irrigation area of Northwest China

Temporal and spatial variations of groundwater salinity in irrigation area are important factors affecting the quality of local groundwater resources and crop growth, especially in the irrigation area that relies on groundwater supply. In this study, the data of groundwater salinity was collected from 21 irrigation areas of the Shiyang River Basin from 1981 to 2003 and interpolated using inverse distance weighting (IDW) method. After considering the impact of natural and social activity in these 20 years, the variation of groundwater salinity was analyzed. The results showed that average annual groundwater salinity in the basin tended to increase generally, and it also increased gradually from upstream to downstream area, the same with its annual fluctuations. The influence of groundwater salinity change on the safety of crop growth and the suitable planting area of the two typical crops (spring wheat and cotton) were also analyzed. The suitable planting areas of both crops tended to decrease slightly. And this study implies the importance of monitoring and control of groundwater salinity in the arid irrigation area that depends on groundwater.