SOIL SPECTRAL PROPERTIES OF ARID REGION, KASHAN AREA, IRAN

This study determined some spectral characteristics and relationship between Landsat spectral reflectance and soil surface color in the arid region of Iran (Kashan). The study carried out in the kashan area that covers 90000 ha. Consisting of mountain, hills and flood plain. Enhanced Thematic Mapper (ETM+) data collected on July 2002 were used for this research. The color composite images produced from ETM+7, ETM+4 and ETM+2 as red, green and blue respectively used in order to choose sample sites. The twelve sample sites were chosen based on resampled 3*3 pixels (90*90 m). In each site, the soil surface conditions and the munsell color of the soil surface were investigated in the field. Some physico-chemical properties of soil samples were also determined in the laboratory. Soil surface particle sizes were categorized into three classes: bare soil 2mm in diameter and vegetated soil. The results of this study indicates that munsell notation of hue, value and chroma are significantly correlated to the visible bands of Landsat (ETM+) data. From this study it may be concluded that visible reflectance of Landsat can be used to estimate soil color, if very precise result is not expected .More investigation are necessary in order to improve the obtained results.