comparison of different indices adopted from landsat images to map soil salinity in the army field of gorgan)

in the past few decades, the use of remote sensing techniques for mapping and monitoring salinity changes in the soils has been developed. for this, this research was done in the army field of gorgan in 2011- 12 to assess possibility of this technique application. in the first step, 101 soil samples were taken from the soil (30 cm depth) during two stages (end of march and start of may) and electrical conductivity (ec) and ph were measured by ec- and ph- meter. then in the next step, different vegetation-based indices such as si1, si2, si3, bi, ndsi, pd322, ipvi and dvi were extracted from etm+ (landsat 7, 7 band, 2012) along with thermal base-compound bands. then brightness value was determined. data correlation between samples was taken and brightness index and accuracy tests on studied indices revealed that sis had the most correlation with ground control points. among sis, si1 and si2 had the most capability to provide salinity maps for dataset 1 (wheat tillering stage, r2= 0.57) and dataset 2 (after wheat harvesting, r2= 0.646), respectively. dvi also was the weakest index for salinity enhancement using both sampling data (rmse=1.68).