مطالعه پذیرفتاری مغناطیسی خاک‏های یک ردیف پستی و بلندی مطالعه موردی: دشت بشار، استان کهگیلویه

نوع مقاله : مقالات پژوهشی

نویسندگان

دانشگاه یاسوج

چکیده

پذیرفتاری مغناطیسی (χ) به میزان گسترده‌ای جهت ارزیابی تکامل خاکرخ‌ها استفاده می‌شود. اندازه‏گیری پذیرفتاری مغناطیسی روشی سریع، غیر تخریبی، ساده و نسبتاً ارزان می‏باشد و در مطالعات مرتبط با پیدایش خاک کاربرد زیادی دارد. از سوی دیگر توالی پستی و بلندی نیز می‌تواند بیانگر تکامل خاک در واحدهای مرتبط با آن ‏باشد. بنابراین به منظور اطلاع از ارتباط بین پذیرفتاری مغناطیسی خاک با میزان تکامل خاک در یک ردیف پستی و بلندی، 11 خاکرخ در واحدهای مختلف فیزیوگرافی در دشت بشار یاسوج حفر و نمونه‏‏برداری انجام شد. پذیرفتاری مغناطیسی نمونههای خاک در فرکانس‏های 46/0و 6/4 کیلوهرتز اندازهگیری شد. به طور کلی نتایج این پژوهش نشان داد که پستی و بلندی، وضعیت زهکشی و کاربری از مهمترین عوامل تاثیرگذار بر تشکیل و تکامل خاک‌های منطقه بوده‌اند. در اغلب خاکرخ‌های مطالعه‌شده مقدار χ با افزایش عمق کاهش می‌یابد و در برخی خاک-ها میزان χ به دلیل انتقال ذرات ریز فرومگنتیک به همراه ذرات رس در افق B حداکثر بوده‌است. بیشترین مقدار پذیرفتاری (به میزان SI*10-87/52) به طور عمده در خاکرخ‌هایی واقع بر سطوح پایدارتر، شرایط زهکشی بهتر و تکامل نسبی بیشتر مشاهده شد. توزیع آهن پدوژنیک (Fed) به میزان زیادی در خاک‌ها با توزیع پذیرفتاری همبستگی نشان داد (R2=0.61). رابطه مثبت و معنی داری بین χ و Fed و همچنین با آهن عصاره‌گیری‌شده با اسید نیتریک (Fen) یا آهن شبه‌کل مشاهده شد. شرایط اکوییک در خاک‌های مورد مطالعه موجب کاهش پذیرفتاری، میزان Fed و نسبت Fed/Fen به ترتیب به میزان 43 ، 44 و 65 درصد شده‌است. این شرایط تفاوت محسوسی بر میزان آهن شبه‌کل نداشته‌است.

کلیدواژه‌ها


عنوان مقاله [English]

Study of Magnetic Susceptibility of the Soils of a Toposequence Case Study: Beshar Plain, Kohgilouye Province

نویسندگان [English]

  • Mahmoud Enjavinejad
  • Hamidreza Owliaie
  • Ebrahim Adhami
Yasouj University
چکیده [English]

Introduction: Magnetic susceptibility measurements can serve a variety of applications including the determination of changes in soil-forming processes, the study of parent material effects, understanding sedimentation processes, soil drainage conditions, and even the separation and identification of soil delineations. The technique is especially attractive since it is relatively rapid, non-destructive, and can be applied to both intact and disturbed samples of soils. Magnetic susceptibility is defined as the ratio of the total magnetization induced in a sample relative to the intensity of the magnetic field that produces the magnetization. Iron oxides are the most abundant of the metallic oxides in most soils; they are present in all climatic regions, in several mineral forms, and at variable concentrations. Typically, selective dissolution techniques are used to quantify the relative proportion of Fe oxides. Due to the large contribution of iron-bearing minerals to magnetic susceptibility, their presence in most soils, and the effects of the biophysical environment on them, pedologists have been paying growing attention to magnetic susceptibility as a means to understand soil and landscape processes. The effects of topography on χ were studied for example by many workers. They found that soil susceptibility changes with the position of a soil profile on a slope. Texture and drainage class assumed to be the main reasons. The soils of the Beshar Plain formed on the relatively same parent materials and are mainly affected by topography and land use. The objective of this study was to examine the role of topography and land use on pedogenic processes and their relation to soil χ, as well as, profile distribution of secondary Fe oxides, and the χ profiles.

Materials and Methods: This study was conducted on the Beshar Plain, Kohgilouye Province, in southwest of Iran. Physiographically this plain comprises hill, piedmont plain, river traces, and plateau. Eleven representative pedons were dug along a transect crossing the main physiographical units. Five pedons demonstrated aquic soil moisture regime. The mean annual temperature and precipitation at the site was 14.7°C and 800 mm, respectively. Soil moisture and temperature regimes of the study area were xeric and thermic, respectively. The soils were classified according to soil taxonomy and WRB. The soil pH was measured in a saturation paste and electrical conductivity (EC) in a saturation extract. Cation exchange capacity (CEC) was determined using sodium acetate (NaOAc) at a pH of 8.2. Soil texture was determined using the pipette method. Calcium carbonate equivalent (CCE) was measured by acid neutralization. Organic carbon was determined by wet oxidation method. Pedogenic Fe (Feo) and pseudo-total Fe (Fen) were extracted with the CBD method and HNO3, respectively.The magnetic susceptibility of bulk samples was determined using a Bartington MS2 meter equipped with the MS2B Dual Frequency sensor, capable of taking measurements at both low (χlf at 0.46 kHz) and high (χhf at 4.6 kHz) frequencies.
Results and Discussion: The soils were classified as taxonomic orders of Entisols, Mollisols, Inceptisols and Alfisols, according to the world reference base for soil resources (WRB) as reference soil groups of Kastanozems, Regosols, Gleysols, Luvisols, Fluvisols and cambisols. The dominant pedogenic processes in the soils were the accumulation of organic matter, the leaching of carbonates, and formation of calcic horizons, the mobilization of clay and development of argillic horizons. The results indicated that the soils are affected mainly by topography, drainage class and land use. Most pedons exhibited maximum of χ at the soil surface, suggesting preferential loss of diamagnetic components, as well as more pedogenic formation of antiferromagnetic minerals. Magnetic measurements showed that the χ values of aquic soils were much lower than those of non-aquic soils (43%). The highest value of χ was noted in pedons which are located on stable physiographic units and the lowest belong to those which are located on river lower terraces. Fed and fen was also positively correlated with χ in the soils studied. Aquic condition also decreased Fed and Fed/Fen, 44 and 65 percent, respectively with no clear effect on Fen. Low to medium amounts of χfd in the studied soils indicated that superparamagnetic gains are not too dominant in the soils. Higher values of χfd were typically observed in the A horizons than at depth, suggesting a greater proportion of ultrafine grains at soil surface. A positive correlation existed between χfd and χ in the soils.

کلیدواژه‌ها [English]

  • Aquic condition
  • Fe oxide
  • land use
  • soil evolution
1- Alexander E.B., and Holowaychuk N. 1983. Soil on terraces along the Cauca river Colombia: Chronosequene charachkeristics. Soil Science Society of America Journal, 47: 721-727.
2- Ayoubi Sh., Amiri S., and Tajik S. 2014. Lithogenic and anthropogenic impacts on soil surface magnetic susceptibility in an arid region of Central Iran. Archives of Agronomy and Soil Science, 60(10): 1467–1483.
3- Boling A.A., Tuong T.P., Suganda H., Konboon Y., Harnpichitvitaya D., Bouman B.A.M., and Franco D.T. 2008. The effect of toposequence position on soil properties, hydrology, and yield of rainfed lowland rice in Southeast Asia. Field Crops Research, 106: 22–33.
4- Bouyoucos G.J. 1962. Hydrometer method improved for making particle size analysis of soils. Agronomy Journal, 54: 464-465.
5- Camargo L.A., Júnior J.M., Pereira J.T., Rabelo A.S. and Bahia D.S. 2014. Clay mineralogy and magnetic susceptibility of Oxisols in geomorphic surfaces.Scientia Agricola, 71(3): 244-256.
6- Chapman H.D. 1965. Cation exchange capacity. In: Black, C.A. (ed.), Methods of soil analysis. American Society of Agronomy, Madison, WI. 2: 891-901.
7- Crockford R.H., and Fleming R.M., 1998. Environmental magnetism as a stream sediment tracer: an interpretation of the methodology and some case studies. Australian Journal of Soil Research, 36: 167–184.
8- Dearing J.A. 1999. Environmental magnetic susceptibility, using the Bartington MS2 System. Kenilworth, UK: Chi Publ. 54 pp.
9- Dearing J.A., Morton R.I., Price T.W., and Foster, I.D.L., 1986.Tracing movements of top soil by magnetic measurements: two case studies. Physics of the Earth and Planetary Interiors, 42: 93–104.
10- Dearing J.A., Hay K.L. Balsan S.M.J. and Huddleston A.S., Wellington E.M.H. and Loveland P.J. 1996. Magnetic susceptibility of soil: An evaluation of contributing theories using a national data set. Geophysical Journal International, 127: 728-734.
11- De Jong E., Nestor P.A., and Pennock D.J. 1998. The use of magnetic susceptibility to measure long-term soil redistribution. Catena, 32: 23–35.
12- De Jong E., Pennock D.J., and Nestor P.A. 2000. Magnetic susceptibility of soils in different slope positions in Saskatchewan, Canada. Catena, 40: 291-305.
13- Feng Z.D. and Johnson W.C. 1995. Factors affecting the magnetic susceptibility of a loess-soil sequence, Barton County, Kansas, USA. Catena, 24: 25-37.
14- Fine P., Singer M.J., Laven R.Verosub K., and Southard R.J. 1989. Role of pedogenesis in distribution of magnetic susceptibility in two California chronosequences. Geoderma, 44: 287- 306.
15- Fine P., Singer M.J. and Verosub K.L. 1992. The use of magnetic susceptibility measurements in assessing soil uniformity in chronosequence studies. Soil Science Society of America Journal, 56: 1195-1199.
16- Grimley D.A., Arruda N.K., and Bramstedt M.W. 2004. Using magnetic susceptibility to facilitate more rapid, reproducible and precise delineation of hydric soils in the Midwestern USA. Catena, 58: 183-213.
17- Holmgren G.G.S. 1976. A rapid citrate-dithionate extractable iron procedure. Soil Science Society of American Proceeding, 31: 210-211.
18- Karimi A., Khademi H., and Ayoubi Sh. 2013.Magnetic susceptibility and morphological characteristics of a loess–paleosol sequence in northeastern Iran. Catena, 101: 56–60.
19- Mokhtari Karchegani P., Ayoubi Sh.,Gao Lu Sh., and Honarjo N. 2011. Use of magnetic measures to assess soil redistribution following deforestation in hilly region. Journal of Applied Geophysics, 75: 227–236.
20- Mullins C.E. 1977. Magnetic susceptibility of the soil and its significance in soil science-A review. Journal of Soil Science, 28: 223-246.
21- Nafeh M. H. and Brussel M. K. 1985. Electricity and magnetism. John Wiley, New York, NY.
22- Nelson D.W. and Sommers L.E. 1982. Total carbon, organic carbon, and organic matter. In: Page, A.L. (ed.), Methods of Soil Analysis, Part 2. American Society of Agronomy, Madison, Wisconsin, pp. 53: 9-579.
23- Oldfield F. 1991. Environmental magnetism - personal perspective. Quaternary Science Reviews, 10: 73–83.
24- Owliaie H.R., Heck R.J. and Abtahi A. 2006a. The magnetic susceptibility of soils in Kohgilouye, Iran. Canadian Journal of Soil Science, 86: 97-107.
25- Owliaie H.R., Heck R.J. and Abtahi A. 2006b. Distribution of magnetic susceptibility in Kohgilouye Boyerahmad soils, southwestern Iran. Proceeding of 18th World Congress of Soil Science. Philadelphia, Pennsylvania. USA.
26- Owliaie H.R., Adhami E., Chakerollhosseini M.R. Rajaie M., and Kasraian A. 2008. Source Evaluation of Magnetic Susceptibility Using CBD Treatment and Micro CT-Scan Images in Some Soils of Fars Province. Journal of Soil and Water Science, 46: 773-787. in Persian with English abstract.
27- Owliaie H.R., Adhami E. Jafari S. Rajaie M., and Ghasemi Fasaei R. 2010. Distribution of magnetic susceptibility in relation to iron compounds in some selected soils of Fars Province. Iranian Research of Water and Soil, 41: 147-159. in Persian with English abstract.
28- Owliaie H.R., and Najafi Ghiri M. 2014. Effect of topography and land use on the soil magnetic susceptibility, Case study: Madvan Plain, Kohgilouye Province. Journal of Soil and Water Science, 40: 159-169. in Persian with English abstract.
29- Quijano L., Gaspar L., Lopez-Vicente M.,Chaparr A.E., Machin J., Navas A. 2011. Soil magnetic susceptibility and surface topographic characteristics in cultivated soils. Latinmag Letters, Volume 1, Special Issue, D10, 1-6. Proceedings Tandil, Argentina.
30- Rhodes J.D. 1996. Salinity: Electrical: conductivity and total dissolved solids. In: Sparks D.L. (ed.) Methods of Soil Analysis. Part 3: chemical methods SSSA. Madison, WI.
31- Richards L.A. (ed.). 1954. Diagnosis and improvement of saline and alkali soils. USDA Handb. No. 60. U.S. Gov.
32- Schwertmann U. and Taylor R.M. 1989. Iron oxides. PP. 379-438. In: Dixon J.B. and Weed S.B. (Eds.), Minerals in soil environment. Soil Science Society of America, Madison, USA.
33- Shakeri S. and Owliaie H.R. 2011. Effect of topography on soil formation of Izadkhast region. Proceeding of the 12th Iranian Soil Congress. Tabriz Univ. pp.131-132.
34- Singer M.J., and Fine P. 1989. Pedogenic factors affecting magnetic susceptibility of California soils. Soil Science Society of America Journal, 53: 1119-1127.
35- Siqueira D.S., Marques J. Pereirab G.T. Teixeiraa D.B. and Vasconcelosc V. 2015. Detailed mapping unit design based on soil–landscape relation and spatial variability of magnetic susceptibility and soil color. Catena, 135: 145-162.
36- Soil Survey Staff, 1993. Soil Survey Manual.USDA. Handbook No. 18.Washington, DC.
37- Spector, C. 2001. Soil Forming Factors : The Story of Rocks and Soil . NASAS Goddard Space Flight Center.
38- Sposito G., Lund L.J. and Chang A.C. 1982. Trace metal chemistry in arid-zone field soils amended with sewage sludge: I. Fractionation of Ni, Cu, Zn, Cd, and Pb in solid phases. Soil Science Society of America Journal, 46: 260–264.
39- Stucki J.W. 1988. Structural iron in smectites. In: Stucki J.W. (ed.), Iron in Soils and Clay Minerals. D. Reidel Publishing Co. Dordrecht, Holland, 1988, 625-675.
40- Thompson R., and Oldfield F. 1986. Environmental Magnetism. Allen and Unwin, London. 227p.
41- Vidic N.J., and Verosub K.L. 1999.Magnetic properties of soils of the Ljubjana Basin chronosequences, Slovenia. Chin. Sci. Bull. 44:75–80.
42- Wang S.P., Shou G.S., Gao S.H. and Guo J.P. 2005. Soil organic carbon and labile carbon along a precipitation gradient and their responses to some environmental changes. Pedosphere, 15(5): 676-680.
43- Williams R.D., and Cooper J.R., 1990. Locating soil boundaries using magnetic susceptibility. Soil Science, 150 (6): 889–895.
44- Yu J.Y.and Lu S.G., 1991. Soil Magnetism. Jingxi Science and Technology Press, Nanchang.
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