نوع مقاله : مقاله پژوهشی

نویسندگان

1 استادیار گروه علوم خاک دانشکده کشاورزی دانشگاه ارومیه

2 دانشیار گروه علوم خاک دانشکده کشاورزی دانشگاه صنعتی اصفهان

چکیده

یک روش آزمایشگاهی برای تعیین سریع و قابل اطمینان آب قابل استفاده خاک برای گیاه (SAW) بر اساس مفاهیم آب قابل دسترس (PAW)، دامنه رطوبتی با حداقل محدودیت (LLWR) و گنجایش آب انتگرالی (IWC) پیشنهاد و کارایی آن ارزیابی شد. نگهداشت آب (θ) برای 20 خاک کشاورزی در 13 مکش ماتریک (h) توسط دستگاه­های جعبه شن و صفحه فشاری تعیین شده و برای برازش مدل ون­گنوختن منحنی مشخصه رطوبتی خاک در روش مبنا (مرجع) به کار رفت. برای منحنی مشخصه رطوبتی خاک در روش پیشنهادی تنها از h­های صفر، 330 و hPa 15000 استفاده شد. مقاومت فروروی (Q) 10 نمونه دست­نخورده در رطوبت­های مختلف برای هر خاک با استفاده از ریزفروسنج در آزمایشگاه اندازه­گیری شد. به غیر از PAW با فرض h برابر hPa 100 برای گنجایش زراعی، تفاوت معنی­داری بین میانگین مقادیر مختلف SAW محاسبه­شده با روش پیشنهادی و روش مبنا وجود نداشت. روابط رگرسیونی خطی قوی بین مقادیر نظیر SAW محاسبه­شده با روش پیشنهادی و روش مبنا به دست آمد. بنابراین بدون نیاز به اندازه­گیری­های زمان­بر منحنی­های مشخصه رطوبتی و مقاومت فروروی خاک در h­های مختلف، تنها با اندازه­گیری مقدار نگهداشت آب خاک در h­های صفر، 330 و hPa 15000 و اندازه­گیری سریع مقاومت فروروی در رطوبت­های مختلف می­توان کمیّت­های مختلف آب قابل استفاده خاک برای گیاه را تعیین نمود. روابط خطی منفی و معنی­دار بین مقادیر PAW، LLWR و IWC با چگالی ظاهری نسبی (RBD) در خاک­های مورد بررسی، نشان داد که مقادیر SAW محاسبه­شده با روش پیشنهادی حساس به شرایط ساختمانی خاک بوده و می­توانند به عنوان شاخص­های کیفیت فیزیکی خاک استفاده شوند. نتایج بدست­آمده مؤید مفید­بودن این روش برای بدست­آوردن سریع و قابل اطمینان شاخص­های آب قابل استفاده خاک برای اهداف کاربردی و برنامه­ریزی آبیاری است. 

کلیدواژه‌ها

عنوان مقاله [English]

Proposing and Evaluating a Laboratory Method for Quick Determination of Different Quantities of Soil Available Water to Plant

نویسندگان [English]

  • Hossein Asgarzadeh 1
  • Mohammad Reza Mosaddeghi 2

1 Department of Soil Science, College of Agriculture, Urmia University, Urmia

2 Department of Soil Science, College of Agriculture, Isfahan University of Technology, Isfahan

چکیده [English]

A laboratory method was proposed and its capability was evaluated for quick and reliable determination of soil available water (SAW) for plant using concepts of plant available water (PAW), least limiting water range (LLWR) and integral water capacity (IWC). Water retention (θ) of 20 agricultural soils was detemined at 13 matric suctions (h) using sand box and pressure plate apparatuses. These data were fitted by the van Genuchten model and considered as the reference method. We used the soil water retention at h values of 0, 330 and 15000 hPa for the model fitting in the proposed method. Penetration resistance (Q) was measured on 10 undisturbed cores at different water contents for each soil using a lab micropenetrometer. Except for PAW (with h of 100 hPa considered as field capacity), there were not significant differences between the mean values of SAW determined by the reference and proposed methods. Strong regression lines were obtained between corresponding SAW values calculated by the two methods. Therefore, it is not needed to measure soil water retention and penetration resistance curves at several h values; instead water retention measurement at h values of 0, 330 and 15000 cm and quick measurement of penetration resistance at different water contents could be used for determination of different quantities for SAW. The PAW, LLWR and IWC were negatively and significantly regressed with relative bulk density (RBD) in the studied soils. These findings show that the SAW values calculated by the proposed method are susceptible to soil structure and might be considered as soil physical quality indices. The results showed suitability of the proposed method for quick and reliable determination of soil available water quantities which are useful for applied purposes and irrigation scheduling.

کلیدواژه‌ها [English]

  • plant available water
  • least limiting water range
  • integral water capacity
  • water characteristic curve
  • penetration resistance
References
Asgarzadeh H, Mosaddeghi MR, Mahboubi AA, Nosrati A and Dexter AR. 2010. Soil water availability for plants as quantified by conventional available water, least limiting water range and integral water capacity. Plant Soil, 335: 229–244.
ASTM. 1992. Annual book of ASTM standards. American Society for Testing and Materials, Philadelphia, PA.
Bengough AG, Bransby MF, Hans J, McKenna SJ, Roberts TJ and Valentine TA. 2006. Root responses to soil physical conditions; growth dynamics from field to cell. Journal Exp. Bot. 57: 437–447.
Betz CL, Allmaras RR, Copeland SM and Randall GW. 1998. Least limiting water range: traffic and long term tillage influences in a Webster soil. Soil Sci. Soc. Am. J. 62: 1384–1393.
Da Silva AP, and Kay BD. 1997. Estimating least limiting water range of soils from properties and management. Soil Sci. Soc. Am J. 61: 877–883.
Da Silva AP, and Kay BD. 2004. Linking process capability analysis and least limiting water range for assessing soil physical quality. Soil and Tillage Research, 79: 167–174.
Da Silva AP, Kay BD and Perfect E. 1994. Characterization of the least limiting water range of soils. Soil Sci. Soc. Am. J. 58: 1775–1781.
De Vos BM, Van Meirvenne, Quataert P, Deckers J, Muys B. 2005. Predictive quality of pedotransfer functions for estimating bulk density of forest soils. Soil Sci. Soc. Am. J. 69: 500–510.
Dexter AR, 2004. Soil physical quality; Part I. Theory, effects of soil texture, density, and organic matter, and effects on root growth. Geoderma, 120: 201–214.
Dexter AR, Czyż EA, and Gaţe OP. 2007. A method for prediction of soil penetration resistance. Soil and Tillage Research, 93: 412–419.
Gee GW and Bauder JW. 1986. Particle size analysis. In: Klute A (ed.), Methods of soil analysis, Part 1: Physical and mineralogical methods. 2nd Edition, Agron Monogr 9. ASA/SSSA, Madison, WI. 383−411 p.
Groenevelt PH, Grant CD and Murray RS. 2004. On water availability in saline soils. Aust. J. Soil Res. 42: 833–840.
Groenevelt PH, Grant CD and Semetsa S. 2001. A new procedure to determine soil water availability. Aust. J. Soil Res. 39: 577–598.
HakanssonI.1990. A method for characterizing the state of compactness of the plough layer. Soil Till. Res. 16: 105–120.
Håkansson I and Lipiec J. 2000. A review of the usefulness of relative bulk density values in studies of soil structure and compaction. Soil Till. Res. 53: 71–85.
Hutson JL and Cass A. 1987. A retentivity function for use in soil-water simulation models. J. Soil Sci. 38: 105–113.
Karlen DL. 2004. Soil quality as an indicator of sustainable tillage practices. Soil Till. Res. 78: 129–130.
Minasny B and McBratney AB. 2003. Integral energy as a measure of soil-water availability. Plant and Soil, 249:253–262.
Mosaddeghi MR, Morshedizad M, Mahboubi AA, Dexter AR and Schulin R. 2009. Laboratory evaluation of a model for soil crumbling for prediction of the optimum soil water content for tillage. Soil Till. Res. 105: 242–250.
Reynolds WD, Bowman BT, Drury CF, Tan CS and Lu X. 2002. Indicators of good soil physical quality: density and storage parameters. Geoderma, 110: 131–146.
Reynolds WD, Drury CF, Yang XM, Fox CA, Tan CS and Zhang TQ. 2007.Land management effects on the near-surface physical quality of a clay loam soil. Soil Till Res. 96: 316–330.
Reynolds WD, Drury CF, Yang XM and Tan CS. 2008. Optimal soil physical quality inferred through structural regression and parameter interactions. Geoderma, 146: 466–474.
Reynolds WD and Topp GC. 2006. Soil waterdesorption and imbibition: tension and pressure techniques. 981–997 P. In: Carter, M.R., E.G. Gregorich (Eds.), Soil sampeling and methods of analysis, CRC Press Taylor & Francis Group.
Sims JT. 1996. Lime requirement. In: Sparks, D.L. Page, A.L. Helmke, P.A. Loeppert, R.H. Soltanpour, P.N. Tabatabai, M.A. Johnston, C.T. and Sumner, M.E. (Eds.) Methods of soil analysis. Part 3. Chemical methods. ASA/SSSA Madison, Wisconsin, USA. 491–515 p.
Thomas GW. 1996. Soil pH and soil acidity. In: Sparks, D.L. Page, A.L. Helmke, P.A. Loeppert, R.H. Soltanpour, P.N. Tabatabai, M.A. Johnston, C.T. and Sumner, M.E. (Eds.) Methods of soil analysis. Part 3. Chemical methods. ASA/SSSA Madison, Wisconsin, USA. 475–490p.
Van Genuchten MTh. 1980 A closed form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Sci. Soc. Am. J. 44: 892–898.
Veihmeyer FJ, Hendrickson AH. 1927 The relation of soil moisture to cultivation and plant growth. Proc. 1st Intern. Cong. Soil Sci. 3: 498–513.
Veihmeyer FJ and Hendrickson A.H., 1931. The moisture equivalent as a measure of the field capacity of soils. Soil Sci. 32: 181–193.
Verma S and Sharma PK.2008.Long-term effects of organics, fertilizers and cropping systems on soil physical productivity evaluated using a single value index (NLWR). Soil and Till. Res. 98: 1–10.
Walkley and BlackIA. 1934. An examination of digestion method for determining soil organic matter and a proposed modification of the chromic acid titration. Soil Sci. 37: 29–38.