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تورم تناوبی پلیمرهای ابرجاذب در محیط متخلخل خاک | ||
| تحقیقات مهندسی صنایع غذایی | ||
| مقاله 1، دوره 8، شماره 4، اسفند 1386، صفحه 1-18 اصل مقاله (1.82 M) | ||
| نوع مقاله: مقاله پژوهشی | ||
| نویسندگان | ||
| سهیلا ابراهیمی1؛ مهدی همایی2؛ ابراهیم واشقانی فراهانی* 2 | ||
| 1دانشجوی سابق کارشناسی ارشد دانشگاه تربیت مدرس | ||
| 2دانشیار دانشگاه تربیت مدرس | ||
| چکیده | ||
| پلیمرهای ابرجاذب قابلیت جذب مقادیر زیادی آب و مواد غذایی دارند و افزون بر تأمین بهینة آب مصرفی گیاهان هدرروی آب از طریق تبخیر و آبشویی نیزدر آنها بسیار کم است. بنابراین، بررسی رفتاراین مواد در خاک، بهویژه در چرخههای متناوب خشک و ترشدن ضروریاست. هدف از این پژوهش، بررسی رفتار تورم تناوبی دو نمونه پلیمر از خانواده پلیآکریل آمید با نام اختصاری "طراوت 100A-" و "طراوت 200A-" و تعیین توانایی آنها در جذب آب، در چرخههای مکرر خشک و ترشدن در محیط متخلخل خاک است. بدین منظور، رفتار تورمی ایندو پلیمر در دو نوع خاک لوم و شنی بررسی شد. تیمارها شامل 0،25/0، 5/0، 75/0، و 1 گرم پلیمر در کیلوگرم خاک با سه تکرار بود. مقدار آب خاک برای هر تیمار در فشارهای 0، 100،300، 500،1000، 3000، 5000، 15000 کیلوپاسکال اندازهگیری شد و منحنیهای رطوبتی برای هر نمونه آزمایشی بهدست آمد. نمونهها در آون خشک و دوباره مرطوب شدند. این روند 5 بار تکرار و منحنیهای رطوبتی مربوطه برای تمام دورهها ثبت شد. نتایج نشان داد در هر مکش، با افزایش مقدار پلیمر در خاک، رطوبت حجمی خاک افزایش مییابد. بیشترین دامنة تاثیر پلیمر بر قابلیت نگهداشت آب خاک در مکشهای پایینتر (5000-0 کیلوپاسکال) مشاهده شد. همچنین، در تمام دورههای تر- خشکی و در هر مکش مقدار نگهداشت آب خاک در پلیمر طراوت 200A- بیشتر از طراوت 100A- بود. در هر دو نوع پلیمر و در همه تیمارهای به کار برده شده، افزایش ناگهانی رطوبت حجمی خاک- پلیمر از دوره اول به دوم، مشاهده شد. از سیکل دوم تا چهارم، رطوبت حجمی خاک- پلیمر در هر دو نوع پلیمرتغییرات همسویی نشان داد. در تناوب پنجم، پلیمر 100T-A افتی جزیی نسبت به دوره قبل نشان داد. بررسی پارامتریک منحنیهای رطوبتی هر دو پلیمر نیز نشان داد که با افزایش مقدار پلیمر کاربردی، پارامترهای qs،n، وqr در تمام تیمارها افزایش مییابد، اما تغییرات پارامترqr چندان قابل توجه نبود. مقدار پارامتر αبرای هر دو پلیمر در خاک شنی کاهش و در خاک لومی افزایش یافت. | ||
| عنوان مقاله [English] | ||
| Cyclic Swelling of Superabsorbent Polymers in Soil Porous Media | ||
| چکیده [English] | ||
| Both arid and semi-arid regions, which make up the greatest portion of the earth, suffer from a lack of precipitation and unsuitable water distribution. The agricultural sector consumes most of the fresh water resources in comparison with other sectors. Thus, it is important to increase water use efficiency (WUE) and practical ways to maintain soil water. Superabsorbent polymers are water containers that absorb and retain large quantities of water when applied to the soil. These materials release the absorbed water, allowing the plants to consume adequate amounts of water at all growth stages. This study investigated the cyclic swelling behavior of superabsorbent polymers. Two polymers, TA-100 and TA-200, were applied to loamy and sandy soils. The treatment levels consisted of 0, 0.25, 0.5, 0.75 and 1 gr of both polymers per kg of dry-weighed soil in 3 replicates. The water content for each treatment was measured at 0, 100, 300, 500, 1000, 3000, 5000 and 15000 kPa and soil water retention curves (WRC) were obtained for each soil sample. The samples were then oven-dried and re-wetted five times and the WRCs were again obtained. The results indicated that, by applying more polymers to the soil, the water content at any soil water pressure head increased. However, this influence declined for the next four drying-wetting cycles. The most dominant influence of the superabsorbent polymers on water retention for each drying-wetting cycle appeared in the lower soil water pressure heads (0-5000 kPa). A comparison of the TA-100 and TA-200 polymers indicated that the TA-200 has a larger water retention capacity and also appeared to absorb more water than did the TA-100 during the subsequent four cycles. Parametric analysis of the retention curves indicated that qs و n and qr parameters in all treatments increased when more polymer was applied. However, the variation of magnitude of qr was small. It was also observed that when any type of superabsorbent was applied, the α parameter decreased in sandy soil and increased in loamy soil. | ||
| کلیدواژه‌ها [English] | ||
| Cyclic Swelling, polymer, Retention Curve, superabsorbent, water holding capacity | ||
| مراجع | ||
|
Abraham, J. and Rajasekharan Pillai, V. N. 1995. N, N-methylene bisacrylamide-crosslinked polyacrylamide for controlled release urea fertilizer formulations. Communication Soil Sci. Plant Analysis. 26, 3231-41.
Aly, S. M. and Letey, J. 1991. Physical properties of sodium-treated soil as affected by two polymers. Soil Sci. Soc. Am. J. 54, 501-504.
Anon. 1999. Iran's agriculture in a view. Ministry of Agriculture. Department of Planning and Budget. (in Farsi)
Baasiri, M., Ryan, J., Mucheik, M. and Harik, S. N. 1986. Oil application of a hydrophilic conditioner in relation to moisture, irrigation frequency and crop growth. Communication Soil Sci. and Plant Analysis. 17, 573-589.
Barati, A. 1994. Optimmal conditions for agricultural Hydro-gels. M. Sc. Thesis. Faculty of Chemical Engineering. Tarbiat Modares University. Tehran. Iran. (in Farsi)
Bres, W. and Weston, L. A. 1993. Influence of gel additive on nitrate, ammonium, and water retention and tomato growth in a soilless medium. Hort. Sci. 28, 1005-1007.
Brooks, R. H. and Corey, A. T. 1964. Hydraulic properties of porous media. Hydrology Paper. No. 3. Colorado State Unit, Forth Collins, Co.
Callebaut, F., Gabriels, D. and Boodt, M. De. 1981. Time responses of sugar beet germination, oxygen diffusion and redox potential to crust formation, polyacrylamide stabilization and peroxide fertilization. Geoderma. 25(3,4): 275-283.
Carter, D. L., Westermann, D. T., Sojka, R. E., Mcek, B. D., Wright, J. L., Brown, M. J. and Lehrsch, G. A. 1995. Controlling nitrate leaching and erosion on irrigated land. Clean water, clean environment. Proceeding of 21st Century Term Agriculture Working to Protect Water Resources Conference.
Cook, D. F. and Nelsons, S. D. 1986. Effect of polyacrylamide on seedling emergence in crust-forming soils. Soil Sci. 141, 328-333.
Grula, M. M., Huang, M. L. and Sewell, G. 1994. Interaction of certain polyacrylamides with soil bacteria. Soil Sci. 158, 291-300.
Gupta, S. C. and W. E. Larson. 1979. Estimating soil water retention characteristics from particle size distribution, organic matter content, and bulk density. Water Resour. Res. 15, 1633-35.
Hamphil, D. D. 1982. Hort. Sci. 17, 256.
Johnson, M. S. 1984. Effect of soluble salts on water absorption by zel-forming soil conditioners. J. Sci. food Agric. 35, 1063-66.
Johnson, M. S. 1984. The effects of gel-forming polyacrylamides on moisture storage in sandy soils. J. Sci. Food Agric. 35, 1196-1200.
Kazanskii, K. S. and Dubrouski, S. A. 1992. Chemistry and physics of agricultural hydrogels. J. AdvancePolymer Sci. 101, 97-133.
Lentz, R. D. and Sojka, R. E. 1994. Field results using polyacrylamide to manage furrow erosion and infiltration. Soil Sci. 158, 274-292.
Leong E. C. and H. Rahardjo. 1997. Review of soil- water characteristic curve equations. J. Geotech. Geoenvir. Eng. 123, 1160-70.
Levin, J., Ben Hur, M., Gal, M. and Levy, G. J. 1991. Rain energy and soil amendments effects on infiltration and erosion of three different soil types. Australian J. Soil Res. 29, 455-465.
Levy, G. J., Levin, J., Gal, M., Benttur, M. and Shainberg, I. 1992. Polymers effects on infiltration and soil erosion during consecutive simulated sprinkler irrigation’s. Soil Sci. Soc. Am. J. 56, 902-907.
Malik, M., Amrhein, C. and Letey, J. 1991. Polyacrylamide to improve water flow and salt removal in a high shrink-swell soil. Soil Sci. Soc. Am. J. 55, 1664-67.
Mitchell, A. R. 1986. Polyacrylamide application in irrigation water to increase infiltration. Soil Sci. 141, 353-358.
Nadler, A. and Letey, J. 1989. Organic polyanions effect on aggregation of structurally disrupted soil. Soil Sci. 148, 346-354.
Nadler, A. and Steinberger, Y. 1993. Trends in structure, plant growth, and microorganisms interrelations in the soil. Soil Sci. 155, 114-122.
Norton, L. D. 1992. Chemical amendments for erosion control. International Winter Meeting. American Society of Agricultural Engineers. Dec. 15-18. Nashville. Tennessee.
Padman, D. R. and Porwal, B. L. and Patel, J. C. 1994. Effect of Levels of Irrigation, Nitrogen and Jalashakti on Growth and Yield of Indian Mustard (Brassica Juncea). Indian J. Agronomy. 39,599-603.
Rubio, H. O., Wood, M. K., Cardenas, M. and Buchanan, B. A. 1989. Effect of polyacrylamide on seedling emergence of three grass species. Soil Sci. 141, 355-360.
Shainberg, I., Laflen, J. M., Bradford, J. M. and Norton, L. D. 1994. Hydraulic flow and water quality characteristics in rill erosion. Soil Sci. Soc. Am. J. 58, 1007-1012.
Sharma, P. K. 1988. Interaction of FeSO4 with polyacrylamide and urea formaldehyde in aggregating light - textured soils. Soil Sci. 146, 158-191.
Sojka, R. E. and Lentz, R. D. 1998. Net infiltration and Soil erosion effects of a few ppm polyacrylamid in farrow irrigation water. Proceeding of the Zed International Symposium on Sealing Crusting and Hardsetting Soils: Prouductivity and Conservation. University of Queensland. Brisbane. Australia.
Steinberger, Y., Sarig, S., Nadler, A. and Barnes, G. 1993. The effect of synthetic soil conditioners on microbial biomass. J. Arid Soil Res. Rehabil. 7, 303-306.
Stern, R., Laker, M. C. and Merwe, A. J. V. D. 1991. Field studies on effect of soil conditioners and mulch on runoff from Kaolinitic and Illitic soils. Australian J. Soil Res. 29, 249-261.
Tripepi, R. R., George, M. W., Dumroese, R. K. and Wenny, D. L. 1991. Birch seedling response to irrigation frequency and a hydrophilic polymer amendment in a container medium. J. Environ. Hort. 9, 119-123.
van Dam J. C., Huygen, J. Wesseling, J. G., Feddes, R. A., Kabat, P., van Walsum, P. E. V., Greoenendijk, P. and van Diepen, C. A. 1997. Theory of SWAP Version 2.0. Simulation of water flow, solute transport and plant growth in the soil- water- plant- atmosphere environment. Techn. Doc 45. Starting Centre. Agric. Res. Dep. Wageningen. The Netherlands.
van Genuchten, M. Th. 1980. A closed- form equation for predicting the hydraulic conductivity of soils. Soil Sci. Soc. Am. J. 44, 161-180.
van Genuchten, M. Th., Leij, F. J. and Yates, S. R. 1991. The RETC code for quantifying the hudraulic function of unsaturated soils. EPA/600/2-91/065, US Salinity Laboratory. USDA-ARS. Riverside, CA.
Vogel, T., Huang, K., Zhang, R. and van Genuchten, M. Th. 1996. The HYDRUS code for simulating water flow, solute transport and heat movement in variably-saturated porous media. Version 5.0. Research Rep. 140. USSL. Riverside, CA.
Wallace, A. and Wallace, G. A. 1986. Polyacrylamide (PAM) and soils. Soil Sci. 141, 334-342.
Wang, Y. T. and Bogher, C. A. 1987. Effect of medium incorporated hydrogen on plant growth and water use of two foliage species. J. Environ. Hort. 5(3): 127-130.
Wang, Y. T. and Boogher, C. A. 1989. Hydrophilic polyacrylamide and fertilizer affect growth and water relations of chlorophytum comosum and plectranthus Australis during winter production. Rio-Grande-Val-Hort. Soc. 42, 51-58.
Woodhouse, J. M. and Johnson, M. S. 1991. The effects of gel-forming polymers on seed germination and establishment. J. Arid Environ. 20, 375-380. | ||
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