Evaluation of soil status using RS and GIS technology (Case study: Segzi plain)
The aim of this study was to evaluate the status of the soil criteria for assessment of desertification and comparison of soil criteria maps produced by kriging interpolation with maps produced by help of satellite imagery. Sampling took place in Segzi plain area in eastern Isfahan at a 76043 ha area and numerous indicators of soil samples were determined for each of 34 points. Indices scored based on MEDALUS method and using the geometric mean of indices of soil. The final map of soil condition was obtained from the reflection of different bands of satellite images and kriging interpolation method. The results showed that the percentage of organic matter, percentage of soil gypsum, electrical conductivity and sodium adsorption ratio, are the most important factors affecting the phenomenon of desertification. For soil indicator mapping by kriging, different interpolation methods were used and finally to produce each indicator map the highest accurate method was used. The statistical analysis showed a significant correlation between soil indicators and spectral data of red & green bands and brightness index, and consequently, it is possible to create soil indicator maps with these bands. Accuracy comparison of produced maps showed that maps derived from satellite images are more accurate at soil indicator mapping. The results of this study can be used in review and assessment of the desertification process in similar areas.