Variation in some physical soil properties of soils affected by different climatic conditions for some agricultural lands in the northeast of the city of Sulaymani, Iraq

:this study investigates soil properties and agricultural suitability across five sites in northeast Sulaimani Governorate, Iraq: Sulaimani, Sharbazher, Sharazoor, Halabja, and Qaradagh. The sites exhibit a climatic gradient, with annual rainfall ranging from over 850 mm in Sharbazher to less than 350 mm in Halabja, affecting soil characteristics. Soil samples were analyzed for particle size distribution, pH, salinity, calcium carbonate content, and organic matter. Additionally, soil consistency limits, aggregate stability, shear strength, and permeability were evaluated to assess soil quality for agriculture. Organic matter content influenced soil mean weight diameter (MWD), with Sulaimani silty clay loam having the highest MWD (0.80 mm) and organic matter (16.5 g.kg-1), while Sharazoor's silty clay had a lower MWD (0.51 mm) and organic matter (12.6 g.kg-1). Enhanced organic material improves soil structure and aggregate formation by binding clay particles, increasing aggregate stability by up to 45%. Soil composition affected shear strength, liquid limit, plastic limit, and permeability. Clay content ranged from 25–52%, silt from 38–61%, and sand from 6-30%. The plasticity index varied between 30.1% and 57.9%, indicating medium to high soil plasticity. Higher clay content and bulk density increased shear strength, particularly in Sharazoor and Sharbazher. Moisture content influenced cohesion, with maximum cohesion at specific clay contents (471.2–523.1 g.kg-1) and bulk densities (1.28–1.31 g.cm-3). Increased clay and silt content reduced permeability, while a higher sand content enhanced it. Sodium content reduced permeability by causing clay particle dispersion and pore clogging. Climatic differences significantly influence soil properties. Lower rainfall in Halabja led to higher salinity and pH levels, while higher rainfall in Sharbazher resulted in greater organic matter content and lower salinity. These findings underscore the importance of region-specific soil management practices to enhance soil quality and productivity.