Red Clay Soil Physical and Chemical Properties Distribution Using Remote Sensing and GIS Techniques in Kirkuk City, Iraq

Abstract

This research focuses on the study of the physical and chemical properties of red clay found in the Injana and Fatha Formations. The aim is to establish correlations among various physical and chemical elements using geographic information system (GIS), remote sensing, and a regression analysis model. Laboratory analysis, including X-ray diffraction, was conducted to determine the properties of the clay, as well as nonclay minerals. Statistical Package for the Social Sciences software was utilized for regression analysis to determine property correlations. Landsat 7 and Landsat 8 images were employed to establish relationships between digital numbers and soil properties. The study revealed that the dry density of the Fatha Formation was lower than that of the Injana Formation. Silt content was highest among all samples, ranging from 28% to 93%. The Fatha Formation exhibited a high gypsum rate due to the presence of gypsum layers. Strong positive correlations were observed between gypsum and sulfate, as well as between electrical conductivity and total soluble salt. Multiple linear regression analysis was appropriate for clay properties, with regression coefficients ranging from 0.6 to 0.72. Nonlinear regression yielded better results than linear regression, with high regression coefficients. Landsat images proved valuable for obtaining data in remote or expansive areas. The association between clay characteristics and Landsat 8 provided superior results compared to Landsat 7.