Investigation of distinctive physico-chemical soil correlations for Kirkuk city using spatial analysis technique incorporated with statistical modeling

Abstract

In the sense of challenging economic situation, it is difficult to perform laboratory tests in a whole intended area to define the soil characteristics for whatever task or situation within an entire city. Hence, this study has used the spatial analysis through applying the inverse distance weighted (IDW) technique to integrate with the available data for 56 different soil samples collected from various depths of Kirkuk city. The studied characteristics were mainly classified to physical soil properties included gravel, sand, silt, and clay contents with chemical soil properties included organic and gypsum contents, pH content, sulfur trioxide, and total dissolved solids (TDS) content. Moreover, statistical investigations such as physico-chemical correlation, linear single and linear multi regression models have been applied. The results of this study have focused on constructing thematic digital maps for visualizing different physical and chemical characteristics of Kirkuk soil. In statistical analysis, negative linear correlations are obtained from the relation between the values of the pH, gypsum, organic, and SO3 contents with the increase of the gravel content, whereas a positive linear correlation is attained for the values of TDS content with the increase of the gravel content. Furthermore, the proposed linear multi regression model predicts the pH values reasonably where most of the values were close to the equality line. The obtained digital maps accompanied with the statistical models will provide comprehensive spatial, agricultural, chemical and mechanical visualizations of the nature and morphology of the soils in Kirkuk city.