| چکیده انگلیسی مقاله |
1- Introduction
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- Methodology
This research was conducted on agricultural lands of Ivrig village of Hir in Ardabil (with a geographical location of 38º 10' north latitude and 48º 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 C0, 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 (ɵm), 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- Results
Results 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 Pearson's correlation showed that there is a negative and significant correlation between soil organic carbon and sand and the dispersion ratio (DR). In contrast, there was a positive and significant correlation between soil organic carbon and total silt and soil structural stability index (SSI) at the probability level of 1 %. In our research, a negative and significant correlation was found between the soil erodibility factor (K) and DR index and total sand at the probability level of 1%. Soil erodibility factor (K) significantly correlated with total and water dispersible (WDSi) silt at the probability level of 1%.
4- Discussion & Conclusions
Organic carbon is depleted in Ivrig agricultural soils over time (OC<1 in 76 % of soils). Therefore, it is expected that the soil aggregation process is weak in this area and even according to the results of the experiments, it is possible to assume that some soil aggregates have disintegrated. For these reasons, the amount of water dispersible clay and silt was high in the studied samples. The stability and strength of the soil enhances by increasing the amount of SSI, CFI, and OC indices and decreasing the amount of DR, CDR, WDC, WDSi, and K indices. Therefore, soils with high structural stability are resistant to erosion. According to our data (lower values for SSI, CFI and OC), it can be concluded that the soil structure was weak in Ivrig region soils and these lands are highly vulnerable to erosion factors because of higher values for DR, CDR, WDC, WDSi and soil erodibility factor (K). It seems that organic carbon affects all the studied parameters and indicators and increases the soil's resistance to erosion by increasing the stability of the soil. Increasing soil organic carbon and adopting appropriate agricultural management, including the use of cultivation methods without tillage and minimal tillage, are suitable solutions to protect these lands. |
| نویسندگان مقاله |
مرتضی خانزاده ایوریق | Morteza khanzadeh Ivrig
Department of Soil Science and Engineering, Faculty of Agricultural and Natural Resources, University of Mohaghegh Ardabili, Ardabil
گروه علوم و مهندسی خاک، دانشکده کشاورزی و منابع طبیعی، دانشگاه محقق اردبیلی، اردبیل
اسماعیل گلی کلانپا | Esmaiel Goli kalanpa
Department of Soil Science and Engineering, Faculty of Agricultural and Natural Resources, University of Mohaghegh Ardabili, Ardabil
گروه علوم و مهندسی خاک، دانشکده کشاورزی و منابع طبیعی، دانشگاه محقق اردبیلی، اردبیل
حسین شهاب آرخازلو | Hossein Shahab Arkhazlo
Department of Soil Science and Engineering, Faculty of Agricultural and Natural Resources, University of Mohaghegh Ardabili, Ardabil
گروه علوم و مهندسی خاک، دانشکده کشاورزی و منابع طبیعی، دانشگاه محقق اردبیلی، اردبیل
مهناز علیزاده | Mahnaz Alizadeh
Department of Soil Science and Engineering, Faculty of Agricultural and Natural Resources, University of Mohaghegh Ardabili, Ardabil
گروه علوم و مهندسی خاک، دانشکده کشاورزی و منابع طبیعی، دانشگاه محقق اردبیلی، اردبیل
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