Accuracy Assessment of Soil Salinity Map in Yazd-Ardakan Plain, Central Iran, Based on Landsat ETM+ Imagery

34 Abstract: Soil salinity is an important factor which limits plant growth and reduces crop production at different levels. It pronouncedly occurs in arid and semiarid regions and, therefore with correct information and up to date maps about it, mapping, evaluating and monitoring of soil salinity can be conducted. 48 surface soil samples representing Yazd-Ardakan plain were collected and surface soil salinity was measured. Landsat ETM+ data, that cover the area, were acquired in 2002. Results showed high correlation between ETM+ band 3 and salt concentration expressed by the exponential equation: y = 0.001e and correlation coefficient R=0.58. 0.058x Thus, applying this equation to Landsat band 3, a soil salinity map was prepared.Ten soil samples for investigation of map accuracy was applied. The obtained soil samples and other more ten soil samples which basically had high similarity in spectral reflectance and geomorphological characteristics were used to examine the produced soil salinity map and to assess its accuracy. According to results the produced soil salinity map had an overall accuracy equal to 87% and Kappa index equal to 47% indicating an acceptable accuracy for this classification.