Geo-statistical analysis of surface and sub-surface soil salinity of the irrigation Block of Sardar Sarovar Canal Command

In the study, quantitative estimates were made on the degree of spatial variation of surface (0–30 cm) and sub-surface (30–90 & 90–150 cm) soil salinity. A total of 335 samples were collected randomly at random intersection of 1.75 km × 1.75 km of a square grid covering 25,800 ha area of 9A/7 irrigation block of Sardar Sarovar Canal Command. The descriptive statistics of the data indicated considerable variability of the soil salinity within site. The directional semi-variogram of surface and sub-surface salinity indicated that there was no effect of direction. The isotropic semi-variograms of surface and sub-surface salinity were best fitted to spherical model which indicated that the data are having spatial structure. The range of spatial dependence of soil salinity was 6.64, 5.80 and 3.32 km, respectively for surface (0–30 cm) and sub-surface layers (30–90 cm and 90–150 cm). The variance of ECe was smaller for surface soils than that for sub-surface soils. Using the spherical variogram, kriged estimates were computed by ordinary kriging and contour maps were prepared. The differences between measured and estimated values were small and the standard deviation of the estimated values was also small which indicated that the model was adequate.