نحوه تشکیل و تکامل خاک های منطقه کوه بیرک- شهرستان مهرستان در سطوح ژئومورفیک مختلف

نوع مقاله : مقالات پژوهشی

نویسندگان

دانشگاه شهید باهنر کرمان

چکیده

استفاده مطلوب و پایدار از خاک در صورتی امکان پذیر است که شناخت صحیح و کامل از خصوصیات آن داشته باشیم. تحقیق حاضر به منظور مطالعه ی نحوه تشکیل و تکامل خاک های منطقه کوه بیرک- شهرستان مهرستان در سطوح مختلف ژئومورفیک انجام گردید. رژیم رطوبتی و حرارتی منطقه به ترتیب، اریدیک و ترمیک می باشد. برای انجام این مطالعه، 8 خاکرخ در سطوح مختلف (پدیمنت سنگی، پدیمنت پوشیده، مخروط افکنه و تراس بالایی) حفر، نمونه برداری و تشریح گردید. نمونه های خاک تحت آزمایش های معمول فیزیکی و شیمیایی، کانی شناسی رسی و میکرومورفولوژی قرار گرفتند. خاک ها بر اساس سیستم رده بندی آمریکایی (2014) و سیستم مرجع جهانی (2014)، رده بندی شدند. سطح ژئومورفیک پدیمنت سنگی در مقایسه با سطوح دیگر، از تکامل بیشتری برخوردار بود که وجود افق آرجیلیک و پتروکلسیک مؤید این مطلب است. سطح پدیمنت پوشیده نسبت به سطوح دیگر دارای بیشترین شوری می باشد. کانی شناسی بخش رس خاک های منطقه، حاکی از وجود کانی های رسی کائولینیت، ایلیت، کلریت، اسمکتیت و پالیگورسکیت می باشد. در سطح پدیمنت پوشیده از پایداری پالیگورسکیت کاسته شده و اسمکتیت کانی غالب می باشد. مطالعات میکرومورفولوژی، نشان دهنده ی وجود پوشش رس و پوشش و پرشدگی آهک در سطح پدیمنت سنگی، پرشدگی آهک در سطح مخروط افکنه و صفحات در هم قفل شده گچ در سطوح پدیمنت پوشیده و تراس بالایی می باشد. نتایج تحقیق، نمایان گر نقش مهم سطوح ژئومورفیک در تغییر پذیری خصوصیات خاک های منطقه مورد مطالعه می باشد.

کلیدواژه‌ها


عنوان مقاله [English]

Genesis and Development of Soils along Different Geomorphic Surfaces in Kouh Birk Area, Mehrestan City

نویسندگان [English]

  • Mohammad Akbar Bahoorzahi
  • Mohammad Hady Farpoor
  • Azam Jafari
ShahidBahonar University of Kerman
چکیده [English]

Introduction: The optimum and sustainable use of soil is only possible with correct and complete understanding of its properties. The objectives of the present research were to study 1) genesis and development of soils related to different geomorphic surfaces in Kouh Birk Area (Mehrestan City), 2) Soil classification according to Soil Taxonomy (2014) and WRB (2014) systems, and 3) physicochemical properties, clay mineralogy and micromorphology of soils.
Materials and Methods: Mean annual rainfall and soil temperature in the selected location are 153.46 mm and 19.6 oC, respectively. From geological point of view, the studied area is a part of west and south west zones and Flysch zone of east Iran. Soil temperature and moisture regimes of this part are thermic and aridic, respectively. Eight representative pedons on different surfaces including rock pediment, mantled pediment, Alluvial fan and Upper terraces were selected, sampled, and described. Routine physicochemical analyses, clay mineralogy, and micromorphological observations performed on soil samples. Soil reaction, texture, electrical conductivity, calcium carbonate, and gypsum were identified. Four samples including Bt horizon of pedon 1, Bk1 horizon of pedon 4, By2 horizon of pedon 5 and Bk1 horizon of pedon 7 were selected for clay mineralogy investigations. Four slides including Mg saturated, Mg saturated treated with ethylene glycol, K saturated, and K saturated heated up to 550 oC were analyzed. A Brucker X-Ray diffractometer at 40 kV and 30 mA was used for XRD analyses. Undisturbed soil samples from Bt horizon of pedon 1, Bk2 horizon of pedon 2, Btn horizon of pedon 3, By2 horizon of pedon 5, Bk1 horizon of pedon 7, and By1 horizon of pedon 8 were selected for micromorphological observations. A vestapol resin with stearic acid and cobalt as hardener was used for soil impregnation. Bk-Pol petrographic microscope was used for micromorphology investigations.
Results and Discussion: Due to the presence of argillic and petrocalcic horizons in rock pediment, soils of this surface were more developed compared to other landforms. High amount of CaCO3 (39.5%) was observed in pedon 4 on rock pediment geomorphic surface which is attributed to calcareous parent material. The presence of argillic horizon in this geomorphic position is due to the more available water of the past climate. The maximum salinity was observed in the mantled pediments. Calcic over gypsic horizons formed in pedon 7 on alluvial fan surface due to higher solubility of gypsum than calcium carbonate. Kaolinite, illite, chlorite, and palygorskite clay minerals were found in pedons 1 and 4 on rock pediment. Palygorskite in this position seems to be pedogenic, but kaolinite, illite, and chlorite are inherited from parent material. Mantled pediment and alluvial fan showed smectite, kaolinite, illite, chlorite, and palygorskite clay minerals. Pedogenic smectite in this position is probably formed from weathering of illite and chlorite. On the other hand, palygorskite stability decreased in mantled pediment surface. This is the reason why smectite was the dominant clay mineral in this landform. Clay and calcite coatings were investigated in Bt horizon of pedon 1 (rock pediment). Coatings and infillings of calcite in Bk2 horizon of the same geomorphic position caused a calcic crystallitic b fabric. A diffused clay coating due to the presence of Na in Btn horizon of pedon 3 in rock pediment was observed. Micromorphological observations of By2 horizon in pedon 5 (mantled pediment) showed gypsum interlocked plates and gypsum infillings. Interlocked plates formed due to re-solubility of gypsum crystals. Micro spars and infillings of calcite are among dominant pedofeatures found in Bk1 horizon of pedon 7 (alluvial fan geomorphic surface). A calcic crystallitic b fabric and Primary calcite mineral were also observed in this pedon. Release of Ca from calcareous parent material caused Ca+2 to SO4-2 ratio to be increased which could be a probable source of gypsum formation. Results of the study showed that more and less developed soils formed on rock pediment and upper terrace geomorphic surfaces, respectively. Illuviation of clay, gypsum, and CaCO3 together with formation of cambic, calcic, petrocalcic, gypsic, argillic, and natric horizons were among the dominant pedogenic processes in studied soils. Paleosols containing Bt horizons were only observed on rock pediment geomorphic surface. Kaolinite, illite, chlorite, and palygorskite clay minerals were observed in almost all surfaces. Smectite was not discovered in rock pediment, but was only investigated in mantled pediment and alluvial fan which could be attributed to higher available moisture of formation time in these surfaces. Secondary calcite and gypsum caused stability of pedogenic palygorskite in soils under study. Micromorphological observations proved the presence of clay and calcite coatings, calcite and gypsum infillings, and gypsum interlocked plates. Gypsum pedofeatures were not observed in rock pediment, but clay and calcite pedofeatures were only found. On the other hand, clay and calcite pedofeatures were not observed in upper terraces and gypsum pedofeatures were the only features determinded in this position.
Conclusion Results of the present research showed that difference in soil characteristics is highly affected by geomorphology.

کلیدواژه‌ها [English]

  • Argillic
  • Clay and Calcite Coating
  • Geomorphology
  • Palygorskite
  • Sistan and Baloochestan
1- Banaei M.H. 1998. Soils Moisture and Temperature Regimes Map of Iran. Soil and Water Research Institute of Iran, Tehran.
2- Boixadera J., Poch R.M., Garcia-Gonzalez M.T., and Vizcayno C. 2003. Hydromorphic and clay-related processes in soils from the Lanosde Moxos (northern Bolivia). Catena, 54: 403-424.
3- Bouyoucos G.J. 1962. Hydrometer method improved for making particle size analysis of soils. Agronomy Journal, 54: 464-465.
4- Bouza P.J., Simon M., Aguilar J., Valle H., and Rostage M. 2007. Fibrous-clay mineral formation and soil evolution in Aridisols of northeastern Patagonia, Argentina. Geoderma, 139: 38-50.
5- Bullock P., Fedoroff N., Jongerius A., Stoops G., and Turina T. 1985. Handbook for Soil Thin Section Description. Waine Research publishing, Albrighton, U.K.
6- Farpoor M.H., Eghbal M.K., and Khademi H. 2004. Genesis and micromorphology of saline and gypsiferousAridisols on different geomorphic surfaces in Nough area, Rafsanjan. Journal of Science and Technology of Agriculture and Natural Resources, 7(3): 71-92. (in Persian with English abstract)
7- Farpoor M.H., and Irannejad M. 2011. Genesis, clay mineralogy and micromorphology of Paleosolslocated on Givdaryalluvial fan, Rafsanjan. Iranian Journal of Crystallography and Mineralogy, 19(4): 761-772. (in Persian with English abstract)
8- Farpoor M.H., Neyestani M., Eghbal M.K., and EsfandiarpourBorujeni I. 2012. Soil–geomorphology relationships in Sirjan playa, south central Iran. Geomorphology, 138: 223–230.
9- Geology and Mineral Exploration Organization of Iran. 2005. Geology Map (1:100000) of Birk (2). (in Persian)
10- Gerrard J. 1992. Soil Geomorphology. Chapman and Hall Pub. Company, Landan.
11- Goudie A. 2004. Encyclopedia of Geomorphology (Vol. 2). Psychology Press.
12- Graham R.C., and Boul S.W. 1990. Soil-geomorphic relations on the Blue Ridge Front. II. soil characteristics and pedogenesis. Soil Science Society of America Journal, 54: 1188-1194.
13- IUSS Working Group WRB. 2014. International Soil Classification System for Naming Soils and Creating Legends for Soil Maps. World Soil Resources Reports No. 106. FAO, Rome.
14- Jackson M.L. 1975. Soil Chemical Analysis-Advanced Course. University of Wisonsin, College of Agriculture, Department of Soil Science, Madison, WI.
15- Jafari M., and Sarmadian F. 2012. Fundamentals of Soil Science and Soil Taxonomy. Tehran University Press. (in Persian)
16- Kemp R.A., and Zarate M.A. 2000. Pliocene pedosedimentary cycles in the southern Pampas, Argentina. Sedimentology, 47: 3-14.
17- Kemp R.A., Tomas P.S., Sayago J.M., Debyshire E., King M., and Wagner L. 2003. Micromorphology OSL dating of the basalt part of the loess-paleosol sequence at La Mesuda in Tucuman Province, northwest Argentina. Quaternary International, 106-107: 111-117.
18- Khademi H., and Mermut A.R. 1998. Source of palygorskitegypsiferousAridisols and associated sediments from central Iran. Clay Minerals, 33: 561-578.
19- Khormali F., and Abtahi A. 2003. Origin and distribution of clay minerals in calcareous soils of arid and semiarid soils of Fars Province, southern Iran. Clay Minerals, 38: 511-527.
20- Khormali F., and Abtahi A. 2003. Origin and distribution of clay minerals in soils of different climatic areas of Fars Province. p. 127-129. In Proceedings of the 8th Soil Science Congress of Iran. (in Persian)
21- Khormali F., Abtahi A., and Mahmoodi S. 2003. Argillic horizon micromorphology in calcareous soils of Fars Province. p. 192-194. In Proceedings of the 8th Soil Science Congress of Iran. (in Persian)
22- Khormali F., Abtahi A., Mahmoodi S., and Stoops G. 2003. Argillic horizon development in calcareous soils of arid and semi-arid regions of southern Iran. Catena, 776: 1-29.
23- Kittrick J.A., and Hoppe E.W. 1963. A procedure for the particle size separation of soils for X-ray diffraction analysis. Soil Science, 96:312-325.
24- Mahjoory R.A. 1975. Clay mineralogy, physical and chemical properties of some soils in arid regions of Iran. Soil Science Society of America Proceedings, 39: 1157-1164.
25- Millot G. 1970. Geology of Clay. Masson. Et Cie., Paris.
26- Moazallahi M., and Farpoor M.H. 2012. Soil genesis and clay mineralogy along the xeric–aridicclimotoposequence, south central Iran. Journal of Agricultural Science and Technology, 14: 683-696.
27- Natural Resources and Watershed Management Organization of Sistan and Baluchestan. 2009. Detailed- Executive Studies of Bakhti Watershed, Zaboli. 10: 1-20. (in Persian)
28- Nazari N. 2003. Morphological and Physiochemical Properties and Mineralogy of Soils and their Genesis and Classification along a Toposequence in RejeinArea of Mianeh, East Azarbaijan Province. MSc Dissertation, Faculty of Agriculture, Department of Soil Science, University of Shiraz. (in Persian with English abstract)
29- Nelson R.E. 1982. Carbonate and gypsum. p. 181-196. In A.L. Page et al. (ed.) Methods of Soil Analysis. Part 2. 2nd ed. Agron. Monogr. 9. ASA and SSSA, Madison, WI.
30- Owji M.R., and Baghernejad M. 2007. Physicochemical, morphological and mineralogical properties of some soils in high plains of Fars Province. In Proceedings of the 6th Soil Science Congress of Iran. Ferdowsi University of Mashhad (in Persian)
31- Page S.E., Wust R.A.J., Wriss D., Rieley J.O., Shotyk W., and Limin S. 2004. A record of late Pleistocene and Holocene carbon accumulation and implication for past, present and future carbon dynamics. Journal of Quaternary Science, 19: 625-635.
32- Sanjari S., and Brumand N. 2014. Clay mineralogy of soils located on different geomorphic surfaces in Sarduieh-Jiroftarea. Journal of Soil Researches, 28(1):209-219. (in Persian with English abstract)
33- Schaefer C., and Dalrymple J. 1996. Pedogenesis and relation properties of soils with columnar structure from Roramia, north Amazonia. Geoderma, 71: 1-17.
34- Schoeneberger P.J., Wysocki D.A., Benham E.C., and Soil Survey Staff. 2012. Field Book for Describing andSampling Soils, Version 3.0. Natural Resources Conservation Service, National Soil Survey Center, Lincoln, NE.
35- Shankar N., and Achyutan H. 2007. Genesis of calcic and petrocalcic horizons from Comibatore, Tamil Nadu: micromorphology and geochemical studies. Quaternary International, 175:140-154.
36- Singer A. 1989. Palygorskite and sepiolite group minerals. p. 829-872. In J.B. Dixon et al. (ed.) Minerals in Soil Environments. Soil Science Society American, Madison, WI.
37- Soil Survey Staff. 2014. Keys to Soil Taxonomy,12th edition. USDA-Natural Resources Conservation Service, Washington, DC.
38- Stoops G. 2003. Guidelines for the Analysis and Description of Soil and Regolith Thin Sections. SSSA, Madison, WI.
39- Toomanian N., Jalalian A., and Eghbal M.K. 2001. Genesis of gypsum enriched soils in north-west Isfahan, Iran. Geoderma, 99(3): 99-224.
40- Verheye W., and Stoops G. 1973. Micromorpholoical evidence for identification of an argillic horizon in Terra Rossasoils. p. 817-831. In G.K. Rutherford (ed.) Soil Microscopy. The Limestone Press, Kingston, Canada.
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