Evaluation of Soil Salinity Using Digital Image Processing of Landsat Satellite in Qhahavand Plain (Hamadan Province)

Remote sensing technology is a useful tool for spatial and temporal monitoring of some natural phenomenon. Salinization and alkalization are known to be the main causes of soil fertility degradation in regions where land and water resources are improperly managed. in Hamadan province, the total area of saline and sodic lands is estimated at 70000 hectares, which includes 9.5 percent of the total cultivated lands of the province. The objective of this study was to monitor saline and sodic soils using satellite information (landsat-5 and 7). Classification of satellite imagery for salinization and alkalization was carried out by investigating various bands and indices. The supervised classification method was used to classify the images. The soil maps were prepared via geographic information system at 1:50,000 scale. Results showed that the area of saline and sodic soils have increased during the last 11 years by 31.9 percent. The change in low to medium salinity class (S0) was 7.9 percent, while in the medium to severe salinity class (S1) it was 31.2 percent. The area of the bare soils that was previously 3005 hectares is now estimated to be 8446 hectares, showing an increase of 181 percent.