Spatial variability of soil salinity ions in the saline area of the Yili River Basin

Geostatistics combined with GIS was applied to collect 60 samples and analysis was made of the spatial variability of soil salt(total salt,Ca2+,Mg2+,K+,Na+,SO42-,Cl-,CO32-and HCO3-) in top soil(0～20 cm) from about 400 km2 of typical saline soil of study area in the Yili River Basin.The results indicated that the total salt,Ca2+ and HCO3-showed a normal distribution,and the others a lognormal distribution.The chemical analysis of semivariograms indicated that the total salt was best described by spherical model,Mg2+,K+,Na+,Cl-,SO42-,CO32-and Ca2+ were best described by Gauss model,and HCO3-showed pure nugget effect.The ranges of soil salinity were from 3.5～22.1 km.The spatial variability of all soil salinity ions were mainly produced by structural factors and random factors.The results also showed that except HCO3-,the spatial correlation of other tested parameters,were moderately dependent,but their spatial heterogeneity degree was different.The Kriging method was applied to estimate the unobserved points and then the precise contour maps were obtained.By this way,the spatial variability of soil salinity ions could be reflected directly.