ارتباط بعد فرکتالی توزیع اندازه ذرات با برخی خصوصیات فیزیکی خاک

نوع مقاله: مقاله پژوهشی

نویسندگان

1 دانشگاه تبریز

2 دانشگاه رشت

چکیده

بعد فرکتالی (Dm) توزیع ذرات خاک (<2mm) به عنوان ابزار مناسبی جهت تخمین خصوصیات مرتبط با بافت خاک معرفی شدهاست. هدف از این تحقیق بررسی ارتباط بین Dm با برخی خصوصیات فیزیکی نظیر اجزاء بافت (شن، سیلت و رس)، تخلخل و هدایت هیدرولیکی موثر (Ke) خاک می‌باشد. بدین منظور 36 سری خاک با خصوصیات متفاوت از منطقه شمال‌غرب ایران انتخاب و نمونه‌برداری شد. توزیع اندازه ذرات در بخش سیلت و رس به روش هیدرومتری و در بخش شن به روش الک کردن تعیین و Dm با استفاده از مدل بیرد و همکاران محاسبه گردید. موادآلی به روش اکسایش تر و تخلخل کل خاک به روش توزین اندازه­گیری گردید. هدایت هیدرولیکی موثر خاک با استفاده از باران سازی با فلوم شیب‌پذیر به ابعاد 0/1×5/0 متر در شیب 9% و در سه شدت بارندگی 20، 37 و 47 میلی‌متر بر ساعت تعیین گردید. تجزیه آماری نتایج نشان داد که Dm همبستگی مثبت و معنی‏داری با مقادیر رس (**963/0)،  سیلت (**371/0) و تخلخل کل (**642/0) و همبستگی منفی و معنی‏داری با درصد شن (**748/0) و میانگین هندسی قطر ذرات (**814/0) خاک داشته است. بنابراین Dm می‌تواند در شبیه‏سازی اجزاء بافت و کلاس بافت خاک کاربرد داشته باشد. همبستگی بالای Dm با تخلخل خاک نیز گویای آن است که مقادیر بزرگ‏تر Dm با خود تشابهی بیشتر توزیع اندازه منافذ خاک، در ارتباط می‏باشد.
 

کلیدواژه‌ها

موضوعات


عنوان مقاله [English]

Relationship Between Fractal Dimension of Particle Size Distribution and Some Physical Properties of Soils

نویسندگان [English]

  • A Ahmadi 1
  • MR Neyshabouri 2
  • H Asadi 2
چکیده [English]

Fractal dimension (Dm) of particle size distribution (PSD) has been introduced as a predictor of soil texture-related properties. This study investigates relationships between Dm and some of the physical properties of soils. Samples from 36 soil series with varying properties were collected from northwest of Iran. Sand fraction was determined by sieving, and silt and clay fractions by the hydrometer methods. Fractal dimension of PSD was computed by Bird et al. model. Organic matter content and total porosity of the samples were measured by wet oxidation and gravimetric methods, respectively. A rainfall simulator with drainable tilting flume (1×0.5 m) at 9% slope was employed and the effective hydraulic conductivity (Ke) was calculated at 20, 37, and 47 mm h-1 rainfall intensities. Statistical analysis showed that in contrast to significant and positive correlations occurred between Dm and each of clay (0.963**), silt (0.371**) and total porosity (0.642**), the correlations between Dm and either of sand (0.748**) or geometric mean diameter of particles (dg) were negative (0.748**). Therefore, Dm had significant relations with soil textural fractions and textural classes, and might be used as an integrating index in modeling studies. Results also showed that greater Dm was associated with greater self-similarity in pore size distribution.

کلیدواژه‌ها [English]

  • Fractal dimension
  • Northwest of Iran
  • Physical properties of soils
  • Soil particle size distribution
بیات ح، 1387. ایجاد توابع انتقالی برای پیش‌بینی منحنی رطوبتی از طریق شبکه‌های عصبی مصنوعی (ANNs) و مدیریت گروهی داده‌ها (GMDH) با استفاده از پارامترهای فرکتالی و تجزیه به مولفه‌های اصلی. پایاننامه دکتری گروه خاکشناسی، دانشکده کشاورزی، دانشگاه تبریز.
Anonymous, 1992. Technical manual: Rainfall simulator, EID 340.Voreppe, Deltalab, France.
Arya L and Paris J, 1981. A physico-empirical model to predict soil moisture characteristic from particle-size distribution and bulk density data. Soil Sci Soc Am J 45:1023-1030.
Assouline S and Mualem Y, 1997. Modeling the dynamics of seal formation and its effect on infiltration as related to soil and rainfall characteristics. Water Resour Res 33:1527–1536.
Assouline S and Mualem Y, 2000. Modeling the dynamics of seal formation: Analysis of the effect of soil and rainfall properties. Water Resour Res 36:2341–2349.
Bacchi OOS, Reichardt K and Nova NAV, 1996. Fractal scaling of particle and pore size distributions and its relation to soil hydraulic conductivity. Sci Agric 53: 356-361.
Baumhardt RL, Romkens MJM, Whisler FD and Parlange JY, 1990. Modeling infiltration into a sealing soil. Water Resour Res 26:2497–2505.
Bird NRA, Perrier E and Rieu M, 2000. The water retention function for a model of soil structure with pore and solid fractal distributions. Eur J Soil Sci 51:55– 63.
Flint LE and FlintAL, 2002. Porosity. Pp:241-254. In: Warren AD (ed). Methods of Soil Analysis. Part 4. Physical Methods. Soil Sci Soc Am Inc., USA.
Gee GW and Or D, 2002. Particle-size analysis Pp.255-295. In: Warren AD (ed). Methods of Soil Analysis. Part 4. Physical Methods. Soil Sci Soc Am Inc., USA.
Huang G and Zhang R, 2005. Evaluation of soil water retention curve with the pore-solid fractal model. Geoderma 127:52-61.
Hwang SI, Lee KP, Lee DS and Powers SE, 2002. Models for estimating soil particle-size distributions. Soil Sci Soc Am J 66:1143-1150.
Kutlu T, Ersahin S and Yetgin B, 2008. Relations between solid fractal dimension and some physical properties of soils formed over alluvial and colluvial deposits. J Food Agri Environment 6:445-449.
Lobe I, Amenlung W and du Preez CC, 2001. Looses of carbon and nitrogen with prolonged arable cropping from sandy soils of the South African Highveld. Eur J Soil Sci 52:93-101.
Mandelbrot BB, 1967. How long is the coast of Britain? Statistical self-similarity and fractional dimension. Science 156: 636–638.
Mena M, Deeks LK and Williams AG, 1999. An evaluation of a fragmentation dimension technique to determine soil erodobility. Geoderma 90:87-98.
Millán H, Gonzáles-Posada M, Aguliar M, Domínguez J and Céspedes L, 2003. On the fractal scaling of soil data, particle-size distributions. Geoderma 117:117-128.
Nelson DW and Somners LE, 1996. Total carbon, total organic carbon and organic matter. Pp. 961-1010. In: Sparks DL (ed). Methods of Soil Analysis Part 3: Chemical Methods. Soil Science Society of America, Madison WI, USA.
Pirmoradian N, SepaskhahAR and Hajabbasi MA, 2005. Application of fractal theory to quantify soil aggregate stability as influenced by tillage treatments. Biosystems Engin 90:227-234.
Rieu M and Sposito G, 1991. Fractal fragmentation, soil porosity, and soil water properties: II. Applications. Soil Sci Soc Am J 55:1239-1244.
Su YZ, Zhao HL, Zhao WZ and Zhang TH, 2004. Fractal features of soil particle size distribution and the implication for indicating desertification. Geoderma 122:43–49.
Wang X, Li MH, Liu S and Liu G, 2006. Fractal characteristics of soils under different land-use patterns in the arid and semiarid regions of the Tibetan Plateau, China. Geoderma 134:56–61.
Xu Y, 2004. Calculation of unsaturated hydraulic conductivity using a fractal model for the pore-size distribution. Computers and Geotechnics 31:549-557.