Investigating the distribution of organic carbon and some physical properties related to soil stability in Ivriq region of Ardabil

Evaluating soil stability indices are vital for understanding soil health and managing erosion risks.Soil stability is influenced mostly by soil organic carbon (SOC), water dispersible clay (WDC) and water dispersible silt (WDSi) content and can be estimated by some indices such as dispersion ratio (DR), clay dispersion ratio (CDR), clay flocculation index (CFI), structural stability index (SSI) and soil erodibility factor (K ).Soil organic carbon is considered as a very valuable and key resource for estimation of soil erosion.Organic carbon plays a key role in soil resistance to erosive factors and soil structure stability.Studying the factors affecting soil erosion and identifying areas prone to erosion is essential for proper soil management and use, optimal allocation of soil and water resources, pollution prevention and loss of these two very valuable resources.Therefore, this research was conducted to investigate the distribution of organic carbon and some physical properties related to soil stability in the Ivrig region of Ardabil. 2-MethodologyThis research was conducted on agricultural lands of Ivrig village of Hir in Ardabil (with a geographical location of 38 10' north latitude and 48 31' east).Wheat, barley, potatoes, beans, alfalfa, and chickpeas were the dominant cultivated crops.The average, minimum and maximum annual temperature is 9.8, 3.4 and 15.7 C 0 , respectively, and its annual rainfall is 287.1 mm. 100 soil samples (0-30 cm) were collected from agricultural lands in a nearly regular and undisturbed grid pattern.After air drying and passing through a sieve, moisture (m), organic carbon and soil texture were measured by weighting, walkely-black and hydrometer methods.Also, water dispersible clay and silt were measured by hydrometer method without hexametaphosphate.Soil stability indices (DR, CDR, CFI, SSI) and soil erodibility factor (K) were calculated using related equations.Pearson correlation was also established between output data using SPSS and a parameter classification map was drawn using Arc GIS software. 3-ResultsResults showed that average values of OC, WDC and WDSi content were 0.79, 12 and 45 %.The organic carbon content in 76 % of studied soils was lower than 1 %.Soil stability indices calculated as 0.93, 0.47, 0.53 and 2.23 percentage for DR, CDR, CFI and SSI, respectively.The average content of soil erodibility content (K) was calculated 0.310.The lower values of DR, CDR, WDC, WDSi and K indices and, in contrast, the higher values of SSI, CFI and OC indices refers to high soil stability and high resistance to erosion.The results of