Saline and Sodic mapping using Geostatistics Theory (A case study in western Karoon river land of Khozestan)

The aim of this study was to characterise the spatial variability of soil saline and sodic properties in part of the western Karoon lands in Khozestan province. A total of 120 samples from the 0-30 cm of soil depth in a semi-systematic grid (200*200 m) were collected in order to provide the needed data. pH، pasted soil electrical conductivity (ECe)، particle size distribution، sodium absorption ratio (SAR) and soluble Ca and Mg were measured in these samples. Spatial variability of parameters was investigated using semivariance and the ratio of nugget variance to total variance. Krigin method was used to create map of the needed data. The validation of the maps was evaluated using mean error (ME) and root mean square error (RMSE) between the observed and the estimated values. Results showed that the experimental variogram of chemical properties was fitted with a exponential and spherical model and 4 to 4. 5 km radius was determined for spatial range in these saline and sodic parameters. All of the parameters were moderately to strongly spatially corolated. Spatiall variability of soil chemical properties is a fundamental element of site-specific crop management. The objective dependent based on these results، spatial patterns of chemical properties are linked to parent materials and soil types. Variance maps of these parameters show that ECe، SAR particle size distribution and PH is largely increased by sampling region in neighboring line and also in lower sample density of region.