Spatial heterogeneity of soil salinity in oasis at catchment scale

Aiming at the problem of soil salinization existed inside oasis,a case study was carried out on the oasis at the Sangong River catchment.Spatial variability of soil salinity in the topsoil(020cm)and its relationship with landscape structure were studied with the combination of methods in geo-statistics,GIS and RS.The result revealed that:on catchment scale,the spatial variation in soil salinity was best fitted by exponential model,with F-test showed high level of confidence.At the spatial case of 1.515km,variation in soil salinity showed strong spatial correlation and self-correlation.Mapping of soil salinity by Kriging and comparing it with landscape maps showed that area of soil salinization in old oasis is smaller than that in new oasis,and degree of soil salinization in old oasis is also lower than that in new one.Among all landscapes,cropland was mostly affected by salinity,with 38.8% of the cropland in new oasis moderately affected by soil salinity,and 8.54% in old oasis.