Soil Salinity Mapping in the Sinai Peninsula of Egypt Using Geographic Information System and Remote Sensing Techniques

Abstract

Soil salinity in the arid and semiarid environments is a major concern for the sustainability of agriculture and water management. Salinity problem does exist in Egypt as well. In this study, we attempted to map soil salinity in a narrow strip in Sinai Peninsula. This was accomplished by analyzing surface soil samples for electrical conductivity (EC dS m−1) and using Landsat TM image acquired in 1991 with a 30-m resolution that covered the study area to measure the mean reflectance pixel values at these specific samples’ ground locations. Landsat TM data was preprocessed (geometrical and radiometrical). Forty bands ratios were developed from the 6 TM original bands to select the bands required for this particular need. A correlation matrix was developed to select the best regression model to represent a soil salinity map. Significant correlation was shown between the inverse of 3 reflectance TM bands and the premeasured EC values (r = 0.82, 0.79, 0.62 at 0.01 level for inverse of TM1, TM2, TM7, respectively). Linear regression model, y = c1 + c2(1/TM1) + c3(1/TM2) + c4(1/TM7), with correlation of determination r 2 = 0.72 was developed for soil salinity mapping. Thus, by applying this equation to the inverse of Landsat bands 1, 2, and 7, a soil salinity map was prepared. It is concluded that remote sensing is useful technique and can be considered a reliable, cost-effective, and timely method needed to determine the extent of soil salinity.