بررسی ویژگی‌های فیزیکوشیمیایی و میکرومورفولوژی خاک‌های گچی – قلیائی منطقه شوشاب، استان همدان

نوع مقاله: مقاله پژوهشی

نویسندگان

1 ارزیابی و تناسب اراضی، کانی شناسی، میکرومورفولوژی دانشگاه ملایر

2 گروه علوم خاک دانشگاه ملایر

چکیده

یکی از مسائل اصلی در نواحی خشک و نیمه­خشک محتوای گچ در خاکرخ­ها و شوری خاک است که شامل اراضی غیرقابل کشاورزی بسیاری در ایران هستند و اصلاح این اراضی نیازمند شناخت کامل آنهاست. منطقه شوشاب از جمله این اراضی می­باشد، که تحت اثر شوری و محتوی گچ بالا به مرور زمان سطح زیر کشت آن کاهش یافته است. هدف از این مطالعه نیز بررسی ویژگی­های فیزیکی، شیمیایی و میکرومورفولوژی خاک­های گچی-قلیائی، آن منطقه است. پس از نمونه­برداری از 8 خاکرخ، تجزیه­های فیزیکی و شیمیایی و مطالعات میکرومورفولو­ژی بر روی نمونه­ها صورت گرفت و خاک­ها براساس سامانه رده­بندی آمریکایی رد­بندی شدند. نتایج نشان داد که میزان کربنات کلسیم معادل و گچ خاک با افزایش عمق، زیاد شد. دامنه pH خاک بالا بوده و با عمق تغییری نکرد. حضور گچ، بافت خاک را به سمت اجزاء سیلت و شن متمایل کرد. مقدار سدیم تبادلی در سطح بیشتر و با افزایش عمق خاک، کاهش یافت. مشاهدات میکرومورفولوژی شامل پوشش، زیرپوشش، پرشدگی کامل و ناقص گچ در داخل حفرات و دیواره کانال­ها می­باشد. هم چنین، بلورهای گچ عدسی، ستونی و ریزبلورین در مقاطع نازک مشاهده شدند. شکل عدسی گچ در تمام مقاطع  بدلیل رژیم رطوبتی زریک غالب بود. حضور گچ در منطقه ریزساختار را به مکعبی زاویه­دار و نیمه­زاویه­دار متمایل کرده و منجر به درجه خاکدانگی ضعیف خاکدانه­­ها شده­است. بی­فابریک عمده در مقاطع، بلوری و در برخی موارد نامشخص تشخیص داده شد. به­طور کل وجود نمک و گچ در خاک منطقه وضعیت منافذ و ساختمان خاک را نامطلوب ساخته­است. که یک موضوع جدی زیست محیطی و رشد گیاه محسوب می­گردد. زیرگروه بزرگ جدیدی در زیر رده Xerepts، زیرگروه Gypsic Calcixerepts بر اساس خاکرخ­های مطالعه شده  جهت گنجاندن در رده­بندی خاک، پیشنهاد می­گردد.  

کلیدواژه‌ها


عنوان مقاله [English]

The Study of Physico-chemical and Micromorphological Properties of Gypsiferous-Alkaline Soils in Shoshab area, Hamadan province

نویسندگان [English]

  • Soheyla Hashemi 1
  • Nima Shobyri 2
1 ارزیابی و تناسب اراضی، کانی شناسی، میکرومورفولوژی دانشگاه ملایر
2 Soil Science Deoartment, Malayer University
چکیده [English]

The content of gypsum and salts in soil profiles is one of the major challenges in arid and semi-arid region which comprise un-arable lands in Iran and their reclamation need their complete identification. Shoshab region is one of these lands which areas under cultivation reduced due to high salinity and gypsum content. The purpose of this study was to investigate the physico-chemical and micro-morphological properties of gypsic-alkaline soils in this area. Sampling of eight soil pedons were conducted in order to analysis of physical, chemical and micropedological characteristics and soil profiles were classified according to the Keys to Soil Taxonomy. The results showed that soil gypsum and calcite increased with increasing soil depth. The range of soil pH was high and was not affected by the soil depth. The presence of gypsum induced soil texture to  silt and sand fractions. The exchangeable sodium content was more in surface horizons and reduced with increasing soil depth. Micromorphological observations demonstrated hypocoating, coating, loose continuous, dense complete and dense incomplete infilling of gypsum in voids and channels walls. Lenticular, prismatic, and allabasrtin of gypsum crystals were observed in thin sections as well. Lenticular gypsum form was common in all soil thin sections because of the xeric moisture regime in this region. The dominant presence of gypsum and sodium in the soils induced to angular and sub angular blocky micro-structures and the aggregation effect weakened. The crystallites form was the usual observed b-fabric in all thin sections and in some cases identified as undifferentiated b-fabric. Generally, the existing of salt and gypsum in the soils of this area led to unsuitable soil voids and soil structure which is a serious environmental issue and plant growth promoting.  New great group and subgroups of Xerepts (Gypsic Calcixerepts) are suggested to be included in soil Taxonomy based on the properties of the some studied soil pedons.

کلیدواژه‌ها [English]

  • Alkaline soil
  • Gypsic
  • Voids
  • Structure
Abdelgavad G.M. 1992. Gypsiferous Soil Properties and Management. The Arab center for the studies of arid zones and dry lands. Damascus, Syrian Arab Republic, 68p.

Al-Dabbas A.M., Schanz T., and Yassen M. 2010. Comparison of gypsiferous soils in Samarra and Karbala areas, Iraq. Iraqi Bulletin of Geology and Mining, 6(2): 115-126.

Allison L.E., and Moodi C.D. 1962. Carbonates. In: Black, C.A.  (Ed), Methods of Soil Analysis. Part 2, Soil Science Society of America and American Society of Agronomy, Madison, WI. pp. 1379-1396.

Amit R., and Yaalon D.H. 1996. The micromorphology of gypsum and halite in Reg soils-the Negev desert, Israel. Earth surfaces and landforms, 21: 1127-1143.

 Azizi P., Mahmoodi Sh., Torabi H., Masihabadi M.H., and Homaee M. 2011. Morphological, Physico-Chemical and clay mineralogy investigation on gypsiferous soils in southern of Tehran, Iran. Middle-East Journal of Scientific Research, 7 (2): 153-161.

Banaei M.H. 1998. Soil Moisture and Temperature Regimes Map of Iran. Soil and Water Research Institute of Iran. 589p. (In Persian)

Bower C.A. 1952. Exchangeable cation analysis of saline and alkali soils. Soil Science, 12: 251-261.

Chakherloo1 S., Manafi Sh., and Heidari A. 2014. Ggenesis and micromorphological properties of some saline-sodic soils of the west of Urmia lake. Journal of Soil Management and Sustainable Production, 4(3): 87-111.

Farpoor M.H., Karimianeghbal M., and Khademi H. 2004. Formation and micromorphology of salic-gypsic aridisols in Nogh Rafsanjan area relationship with geomorphic surface.  Soil and Water Science Journal, 7(3): 71-92.

Florea N., and Al-Joumaa Kh. 1998. Genesis and classification of gypsiferous soils of the Middle Euphrates Floodplain, Syria. Geoderma, 87: 67–85.

Gee G.W., and Bauder J.W. 1986. Particle-size Analysis. In: Klute A. (Ed.), Methods of Soil Analysis Part I, Physical and Mineralogical Methods. Soil Science Society of America and American Society of Agronomy, Madison, WI, pp. 383-412.

Hashemi S.S., Baghernejad M., and Khademi H. 2011. Micromorphology of gypsum crystals in southern Iranian soils under different moisture regimes. Journal of agricultural science and Technology, 13: 273-288.

Jafarzadeh A.A., and Burnham C.P. 1992. Gypsum crystallization in soils. Soil Science, 43: 409-421.

Kapur S., Ryan J., Akca E., Celik I., Pagliai M., and Tulun Y. 2007. Influence of Mediterranean cereal based rotations on soil micromorphological characteristics. Geoderma, 142: 318-324.

Kemp R.A., Toms P.S., Sayago J.M., Derbyshire E., King M., and Wagoner L. 2003. Micromorphology and OSL dating of the basal part of the loess-paleosol sequence at La Mesada in Tucuman province, Northwest Argentina. Journal of Quaternary International, 106: 111-117.

Moghiseh A., and Heidari A. 2012. Polygenetic saline gypsiferous soils of the Bam region, Southeast Iran. Journal of Soil Science and Plant Nutrition, 12 (4): 729-746.

Momeni A. 2010. Geographic and salt category of Iran soil resources. Soil and Water Science Journal, 24(3): 203-214.

Murphy C.P. 1986. Thin Section Preparation of Soils and Sediments. Berkhamsted: Academic Publication.

Neyestani M., and Farpoor M.H. 2014. Genesis, clay mineralogy and micromorphology of saline-gypsiferous soils in Kheirabad playa, Sirjan. Arid Biome Scientific and Research Journal, 4 (1): 65-78.

Owliaie H.R. 2012. Micromorphology of pedogenic carbonate features in soils of Kohgilouye, southwestern Iran. Journal of Agriculture Science Technology, 14:225-239.

Owliaie H.R., Abtahi A., and Heck R.J. 2000. Pedogenesis and clay mineralogical investigation of soils formed on gypsiferous and calcareous materials, on a transect, southwestern Iran. Geoderma, 134: 62-81.

Rhoades J.D. 1996. Salinity: Electrical Conductivity and Total Dissolved Solids. In: Sparks D.L. (Ed.), Methods of Soil Analysis, Part III, 3rd Ed., Soil Science Society of America and American Society of Agronomy, Madison, WI, pp. 417-436.

Ryahi A.A., and Khoshfetrat Gh.R. 1985. Soil detailed study of Hosseinabad shamlo lands (Malayer). Ministry of Agriculture, Natural Resources and Agriculture Research Institute, Soil and Water Institute, No. 658.

Servati M., Jafarzadeh A.A., Heydari A., and Shahbazi F. 2013. Evolution of Gypsum and its Pedofeatures in soils on pediment and flood-plain, south of Ahar region, east Azerbaijan, Iran. Journal of Soil and Water Science, 23 (2): 59-70.

Separdar Sh., Delavar M.A., and Sarabchi A. 2009. Mineralogical and micromorphological properties of salt crusts on desert lands Abyek. 11th Iranian Soil Science Congress. Soil management and food security. 12-15 July. Gorgan, Iran. pp. 539-541.

Singh A., and Singh j.K. 2014. Effect of gypsum on the reclamation and soil chemical properties in sodic soils of raebareli district, Uttar Pradesh. International Journal of Scientific Research in Environmental Sciences, 2(12): 429-434.

Stoops, G. 2003. Guide lines for the Analysis and Description of Soil and Regolith Thin Sections. Soil Science Society of America, Medison, WI, USA. 184p.

Stoops G, and Ilowi M. 1981. Gypsum in Arid Soils: Morphology and genesis. Soil Classification Workshop. March. Dodoma, Tanzania. pp. 175-185.

Toomanian N., Jalalian A., and Karimian Eghbal M. 2001. Genesis of gypsum enriched soils in north-west Isfahan, Iran. Geoderma, 99: 199-224.