Determination of soil salinization stage using satellite information and water resourses data via Geographic Information System in Qahavand plain (Hamedan province)

Remote sensing technology is paramount importance for mapping and monitoring of natural phenomenon. Salinization and alkalization is one of the most important fertility of soil degradiation process in regions that have not efficient management in land and water resources. Total area of saline lands in Hamedan province are estimated at 70,000 hectare that includes 9.5 percent of total cultivated lands in this province. In Hamedan township two sides of Qahavand and Famenin with 37331hectare area have exposed salinity and sodisity of soils. The Kabudrahang town ship is the second region that has influenced of salinity and sodicity of soils and total of saline region in this field is at 14800 hectare. In attention to importance of salinity and extensive areas of saline and sodic soils, presentation of a project seems necessary to include all aspects of the subjects. In order to meet this ample take a project titled &ldquoDetermination of soil salinization stage using satellite information and water resources data via geographic information system in Qahavand plain&rdquo, was approved in 2000 and lasting 4 years. This paper tries to show important aspects of applying remote sensing in classification of soil salinity and sodicity analysis and cost effectiveness. The aim of this paper is to distinguish the differences of soils saline and sodic surface by using satellite information (landsat-5 and 7). Classification of satellite imagery for salinization and alkalization was carried out by using investigation of various bands and indexes such as PC1234, PC57 , NDVI, and BRI. In order to classification of images we used supervised classification and spectral response angular mapping algorithm. In order to examination of soil situation, sampling of soils was carried out in the characteristic sites of region and the soil experiments were carried out. In this manner soil maps were prepared via geographic information system in scale 1:50,000. Conclusion of this paper in this area is confirmed of saline and sodic soils existence however in a part of points the mixture of both is seen. Next stage of study included investigation of digital photographs in order to distinguish the differences of land use between 1985-1995. The study of plant vegetation carried out by using of Eco-phytosociological method. By using of Physionomic-Floristic-Ecologic criteria, determination of association individuals and the site of releves installation were possibled. Data analyses were carried out in Anaphyto software by A.F.C and C.A.H methods and it distinguished several plant formations. On the basis studies operated on plant vegetation of saline and sodic lands in different points in region 12 plant associations were recognised. In the recent years the most important reason for extention of saline and sodic soils in this region are non-efficient management in lands & water resources and changes in land employing.