RELATIONSHIP BETWEEN SOIL COLOR AND SOME PROPERTIES OF IRAQI SOIL UNDER DIFFERENT CLIMATIC CONDITIONS

Soil color a basic quality of assessing pedogenesis and climatic effects hence, may provide valuable insight into soil properties and may serve as a distinctive and straightforward measurable climatic indicator. In this study, surface horizons samples were sampled at depth 0-30 cm by using an auger in ten provinces of Iraq where the climate conditions are different. Although the different physicochemical properties such as (Soil Texture pH, EC, O.M. CEC, CaCO3) were identified in the lab section, the Munsell Soil Color Book was applied in the field to identify the soil color. The result showed a rise in (pH, O.M., CEC, CaCO3, Fed, Clay) based on the color indices BWR, TR1, and TR2 in sub-humid climate areas; however, under the same climatic conditions, EC and CaSO4.2H2O levels were lower. While Xanthization was more common in semi-arid areas, the processes of Melanization and Runification were more active in humid environments. Multiple regression analysis indicated a statistically significant relationship between BWR and CaCO3, as well as between TR1 and CaSO4.2H2O. No significant relationship was detected between TR2 and the soil properties under investigation. Furthermore, linear regression analysis between climate and the BWR soil color index demonstrated a significant association, with value R² = 0.33 at a significance level of 0.01. Research findings demonstrated that Iraqi soil climate shows direct correlation to the BWR index specifically.