Mapping Soil Organic Carbon Using IRS-AWIFS Satellite Imagery (Case Study: Dehaghan Rangeland, Isfahan, IRAN)

Abstract

Soil organic matter has positive consequences eht rof quality and productivity<br />of soil and also environment, agricultural and biological sustainability and conservation of<br />biodiversity and soil. Organic matter plays an important role in the physical and chemical<br />processes of soil and thus, it is of a great effect on the spectral characteristics of soil. This<br />study was done in order to develop the mapping surface of soil Organic Carbon (OC) of<br />various land uses, particularly rangelands using remote sensing technology in Dehaghan in<br />the south of Isfahan. The data of IRS-P6 and AWIFS satellites with 49 ground control<br />points and accuracy less than 0.3 pixels were recorded. Stratified random sampling method<br />was used. Soil samples were collected from the depth of 0-15 cm at each point. Bulk<br />density of soil samples was determined according to Hunk method and OC% was<br />computed by Walky-Black method. For the preparation of land use map and False Color<br />Composite (FCC), the supervised classification was conducted using maximum likelihood<br />algorithm and Optimized Index Factor (OIF). In order to map the surface soil OC, the<br />multivariate regression model was fitted using band 2 (red band) as the dependent variable.<br />Red band had a relationship with surface soil OC in the study area. Relationship of the red<br />band and surface soil OC content was negative. IRS-P6 and AWIFS satellite images<br />according to the cover of spectral and spatial resolution were considered as a useful<br />method for the preparation of land use map and the map of surface soil OC levels in the<br />study area.