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نوع مقاله : مقالات پژوهشی

نویسندگان

دانشگاه صنعتی اصفهان

چکیده

فرسایش بادی یکی از اصلی ترین فرآیندهای تخریب اراضی و یکی از جدی ترین مشکلات اکوسیستم و محیط زیست در مناطق خشک و نیمه‌خشک نظیر مناطق مرکزی ایران است. فرسایش بادی در منطقه شرق اصفهان و ناحیه سگزی به علت بهره‌برداری نامناسب از اراضی فقیر، بهره‌برداری از معادن رس و گچ و خشکسالی های اخیرافزایش داشته است. فرآیند درشت شدنبافت خاک (نتیجه کاهش اندازه ریز ذرات خاک)، از دست رفتن مواد آلی و تخریب پوشش گیاهی پیامدهای فرسایش بادی بوده است. بنابراین نیاز به اطلاعات معتبر در مورد شدت فرسایش بادی و تأثیر فرسایش بادی بر روی خصوصیات فیزیکی و شیمیایی خاک برای انجام عملیات حفاظت خاک ضروری می باشد. در این تحقیق به کمک روش
سزیم-137 نقاط فرسایش و رسوب در طول یک ترانسکت در منطقه سگزی (شرق اصفهان) تعیین و سپس اثر فرسایش بادی بر برخی ویژگی های فیزیکی و شیمیائی خاک در نقاط فرسایش و رسوبگذاری بررسی شد. در این پژوهش، درمنطقه مورد مطالعه در طول یک ترانسکت شمال شرقی- جنوب غربی به طول 42 کیلومتر به فواصل 2 تا 5 کیلومتر در 16 نقطه نمونه برداری صورت گرفت. در هر نقطه از اعماق 5-0، 10-5 ، 20-10، 30-20 و50-30 نمونه‌برداری خاک انجام شد و نمونه های برداشت شده مورد آنالیزهای فیزیکی، شیمیائی و اندازه‌گیری محتوای سزیم-137 قرار گرفتند. نتایج این مطالعه نشان داد که در نقاط 1 تا 8، 10 و 12 تا 16 فرآیند فرسایش و در نقاط 9 و 11 فرآیند رسوب‌گذاری اتفاق افتاده است. نتایج نشان داد روش سزیم- 137 می تواند به صورت کمّی میزان فرسایش و رسوب بادی در منطقه مورد مطالعه را تخمین بزند. مقایسه میانگین خصوصیات فیزیکی و شیمیایی خاک در این مطالعه بین مناطق فرسایش، رسوب‌گذاری و مرجع نشان داد فرآیندهای فرسایش و رسوب به شدت ویژگی های فیزیکی و شیمیائی خاک رادر طول ترانسکت تحت تأثیر قرار داده است. این نتایج برگرفته از سزیم-137 برای اولین بار نتایج قابل توجهی برای تحقیقات آینده در مورد فرسایش بادی در مناطق خشک ایران به دست آورد.

کلیدواژه‌ها

عنوان مقاله [English]

Variability of Some soil physical and chemical properties along a transect under wind erosion processes in Segzi district, Isfahan

نویسندگان [English]

  • F. Ghiesari
  • S. Ayoubi

Isfahan University of Technology

چکیده [English]

Introduction: Arid and semiarid environment is the main climatic condition in central Iran, as well as 80 million km 2 of Iran (> 50%) is affected by wind erosion. During the last decades, the area affected by wind erosion and desertification processes has increased as a result of human activity, climate change and recent drought (Karimzadeh, 2001). Thus, it is crucial to control wind erosion in the arid regions of Iran as the most serious environmental problem. In this regard, the information on the rate of soil erosion is needed for developing management practices and making strategic decisions.. Soil erosion rate has increased as a result of improper gypsum and clay mining operations In the Segzi region of Isfahan,. coarsening of the soil texture (as a result of the loss of fine textured materials), depletion of soil organic matter and degeneration of vegetation are wind erosion damages occurred widely. The objective of this study was to estimate wind erosion rates with 137Cs technique, and also to determine changes in soil physical and chemical properties by wind erosion process, along the wind erosion transect across the Segzi district, east of Isfahan.
Materials and Methods: This study was conducted in arid region of east of Isfahan Province. sixteen sites were selected along a northeast- southwest transect with 42 km length. Eighty soil samples were taken from 0-30 cm in 5 cm layer depth sections. Some physical and chemical properties were measured and a reference site with lowest rate of soil erosion and sedimentation was also studied. 137-Cs technique was used for determination of erosional and depositional sites. Analysis of variance was used to compare physical and chemical properties sites to reference site.
Results and Discussion: The results showed that sites of 1 to 8, 10 and 12-16 were identified as erosional sites and two sites of 9 and 11 were recognized as depositional sites. Soil organic matter and total nitrogen contents were reduced significantly In eroded sites compared to reference site. Similarly, clay content was reduced in the eroded sites compared to depositional sites. But,the amount of gypsum and calcium carbonate equivalent increased in eroded sites. Bulk density significantly declined in eroded (23.95%) and depositional (33.33%) sites comparing to reference site. Silt and sand content significantly were increased and decreased in depositional sites respectively compared to reference site. High speed winds caused to translocate the fine and coarser particles to farther and closer distances from detachment locations. Therefore, soil texture was mainly affected by soil erosion and changed to coarser classes. Compare means between physical and chemical properties in the eroded and deposited sites and reference site showed that physical and chemical properties were affected by erosion and deposition processes significantly.
Conclusion: Overall results indicated that Cs-137 is powerful technique for differentiation between erosional and depositional sites in the regions under wind erosion. Moreover, the this study confirmed that eroded and depositional sites wrer significantly affected by wind erosion process and soil attributes were changed compared to reference site. and proper management, especially in gypsum mines of Segzi district should be considered .

کلیدواژه‌ها [English]

  • Wind erosion
  • deposition
  • Cesium-137
  • arid region
1- Azimzadeh H.R., Ekhtesasi M., Hatami M., and AkhavanGhalibaf M. 2002. Effects of some physical and chemical properties on wind soil erodibility and development of a model to estimate it in Yazd Ardekanplain. Journal of Agricultural Sciences and Natural Resources, 9: 1-12 (in Persian with English abstract).
2- Beremmer J.M., and Mulvancey C.S. 1982. Total nitrogen.In: Page A.L. (Ed), Methods of Soil Analysis Part 2: Chemical and Microbiological Properties, second ed. Agronomy Monograph No. 9 American Society of Agronomy, Madison, WI, USA.
3- Blourchi M. 1990. Conservation and Radio-Controlling of Environment. Iranian Atomic Association Pub. 13P. (in Persian).
4- Chepil W.S. 1953. Factors that influence cold structure and erodibility of soil by wind soil texture. Soil Science. 75: 473-483.
5- Darvish M. 1378. Inhibition of desertification. Available at: htpp: //www.mohammaddarvish.ir
6- EkhtesasiM., and Ahmadi H. 1993. Determination of sand dunes sources in Yazd-Ardekan basin, with special attention to morpho-dynamic processes in wind environment. Research center of Natural Resources, Yazd. 171. (in Persian).
7- Hess P.R. 1976. Particle size distribution in gypsic soils. Plant Soil, 44: 241-247.
8- Karimzadeh H.R. 2003. Soil development in various landforms and source determination of wind deposits in eastern Isfahan district. PhD dissertation. College of Agriculture, Isfahan University of Technology, Isfahan. Iran. ( in Persian).
9- Li M., Li Z., Liu P., and Yao L. 2004. Using Cesium-137 technique to study the characteristics of different aspect of soil erosion in the wind-water Erosion Crisscross Region on Loess Plateau of China. Applied Radiation and Isotopes, 62: 109–113.
10- Mahmudabadi M., Dehghani F., and Azimzadeh H.R. 2012. Investigation of particle size distribution effects on wind erosion intensity. Soil Management and Sustainable Production, 1: 1-17.
11- Nelson D.W., and Sommers L.E. 1982. Total carbon, organic carbon and organic matter. In: Page A.L., Miller R.H., Keeney D.R. (Eds.), Methods of Soil Analysis, 2nd edition. Agronomy, Madison, WI, USA.Part 2, pp. 539– 577.
12- Pierre C., Bergametti G., Marticorena B., Abdourhamane A., Toure J.L.,Rajot and Kergoat L. 2014. Modeling wind erosion flux and its seasonality from a cultivated sahelian surface: A case study in Niger. Catena,122: 61-71.
13- Ping Y., Zhibao D., Guangrong D., Xinbaoand Z., and Yiyun Z. 2000. Preliminary results of using 137- Cs to study wind erosion in the Qinghai-Tibet Plateau. Journal of Arid Environments,47: 443-452.
14- Refahi, H. 2005. Wind erosion and its control. Tehran University Press, 3th Edition. 320 p.(in Persian).
15- Sabeti, H. 1995. Trees and Shrubs of Iran. Yazd University Press (in Persian).
16- Salehi, M.H. 1998. Determination of salt accumulation and sources in Segzi plain and their effects on wind erosion. MS.cTheis. Isfahan University of Technology. Isfahan. Iran.
17- Walling D.E., and Quine T.A. 1993. Use of Cs-137 as a tracer of erosion and edimentation. Hand book of the application of Cs-137 techniqes. 195 pages.
18- Weather data. Available at: http: // www. Weather.ir
19- Yan P., and Shi P. 2004. Using the 137-Cs technique to estimate wind erosion in Gonghe basin, Qinghe province, Chine.Soil Science,169: 295-305.
20- Zarrinkafsh M. 1994. Applied Soil Science. Tehran University. 342p. (in Persian).
21- Zhang L.C., Zou X.Y., Yang P., Dong Y.X., Li S., Wei X. H., Yang S., and Pan X.H. 2007. Wind tunnel test and 137Cs tracing study on wind erosion of several soils in Tibet.Soil and Tillage Research, 94: 269–282.
22- Zhao L.H., Yi X.Y., Zhou R.L., Zhou X.Y., Zhang T.H., and Drake S. 2005. Wind erosion and sand accumulation effects on soil properties in Horqin Sandy Farmland, Inner Mongolia. Catena, 65: 71- 79.
23- Zobeck Ted M., and Van Pelt R. 2014. Wind Erosion. Publications from USDA-ARS / UNL Faculty.Paper 1409.http://digitalcommons.unl.edu/usdaarsfacpub/1409
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