نوع مقاله : مقاله پژوهشی

نویسندگان

1 عضو هیئت علمی بخش تحقیقات فنی و مهندسی مرکز تحقیقات کشاورزی و منابع طبیعی گلستان

2 عضو هیئت علمی دانشگاه تربیت مدرس

چکیده

برای توسعه و کاربرد مدل‌های ریاضی برای پیش‌بینی انتقال آب و املاح در شرایط آبیاری، لازم است این­گونه مدل‌ها برای مناطق مختلف واسنجی و ارزیابی شوند.  به همین منظور، مدل SWAP به مدت دو سال زراعی (81-80 و82-81) در زمین تحت کشت گندم در شمال گرگان مورد ارزیابی قرار گرفت؛ این مدل، شرایط مزرعه­ای انتقال آب، املاح و حرارت را در خاک شبیه­سازی می­کند.  داده‌های مورد نیاز این پژوهش با استفاده از چهار سطح آب آبیاری شامل 50 (W1)، 75 (W2)، 100 (W3) و 125 (W4) درصد نیاز گیاه به همراه چهار سطح شوری شامل S1، S2، S3 و S4 جمع­آوری شد که در سال اول به ترتیب برابر 6/1، 9/7، 8/10 و 6/13 و در سال دوم معادل 1، 3/9، 2/12 و 7/14 دسی‌زیمنس بر متر در قالب طرح بلوک‌های کاملاً تصادفی به صورت کرت‌های خردشده با سه تکرار اجرا شده بود.  به استناد تحلیل‌های آماری، با وجود متغیر‌های متعدد در شرایط مزرعه‌ای، مدل SWAP، مقدار رطوبت، شوری خاک، و عملکرد نسبی گندم را به خوبی شبیه‌سازی کرد.  در همة موارد ضریب همبستگی بالاتر از 80 درصد و میانگین مربعات خطا کمتر از انحراف معیار داده‌ها بود.  اما در سال اول و در مرحلة آخر رشد گندم به دلیل فرض زهکشی آزاد برای شرایط مرزی پایین و بالا آمدن سفرة آب زیرزمینی در این زمان، رطوبت خاک در عمق 80 تا 100 سانتی‌متری توسط مدل کمتر از مقادیر واقعی پیش‌بینی­شده بود.  اختلاف مقادیر شبیه‌سازی­شده و مقادیر اندازه‌گیری­شدة تبخیر و تعرق در سال دوم به دلیل فراوانی روزهای بارندگی و در نظر نگرفتن سهم نفوذ عمقی مطلوب نبود.

عنوان مقاله [English]

Evaluating SWAP Model for Simulation of Water and Solute Transport in Soil Profile

چکیده [English]

Many mathematical models have been applied and developed for simulation of water and solute transport in irrigated agriculture. Using a model, it should be first calibrated and validated for different regions. SWAP is a field scale model that simulates water, solute and heat movement in the soil profile. In this study, the SWAP model was evaluated for two years (2001 and 2002) on wheat in a semi-arid area in North of Gorgan. Required data were collected by field experiments. The experiments were consisted of four water quantity levels (50, 75, 100 and 125 percent of crop water requirements) and four water quality levels including S1, S2, S3 and S4 having 1.6, 7.9, 10.8 and 13.6 dS/m in the first year and 1, 9.3, 12.2 and 14.7 dS/m in the second year, respectively. The experimental design was performed by randomized complete block design as a split plot layout with three replications. Based on statistical analysis, results from the simulation of SWAP model were in good agreement with the field measurements of water content (θ), salinity (ECe) along the soil profile and wheat relative yield. In all cases, correlation coefficient (R), was higher than 80 percent and root mean square error (RMSE) was less than standard division (Sd). In the first year, bottom boundary condition was supposed to be free drainage, but due to fluctuations of water table in harvest time, model under predicted soil water content in 80-100 cm depth. Since the high frequency of rainfall (especially in second year) and elimination of deep percolation, the discrepancy between the measured and predicted ET was not satisfied.

کلیدواژه‌ها [English]

  • ET
  • simulation
  • SWAP model
  • Water and solute transport
  • Wheat
Bastiaanssen, W. G. M., Huygen, J., Schakel, J. K. and Van Den Broek, B. J. 1996. Modeling the Soil-Water-Crop-Atmosphere System to Improve Agricultural Water Management in Arid Zone (SWATRE). In: Van Den Broek, B. J. (Ed.). Dutch Experiences Irrigation Water Management Modeling. Report 123. Winand Staring Center. Wageningen. Netherlands.
Bresler, E. and Hoffman, G. J. 1984. Irrigation management for soil salinity control: Theories and tests. Soil Sci. Soc. Am. J.50, 1552-1559.
Clemente, R. S., De Jong, R., Hayhoe, H. N., Reynolds, W. D. and Hares, M. 1994. Testing and comparison  of  three unsaturated soil water flow models. Agric. Water Manag. 25, 135-152.
Doorenbos, J. and Kassam, A. H. 1979. Yield response to water. Irrig. Drain. Paper 33. FAO. Rome.
Dorji, M. 2003. Integration of SWAP model and sebal for evaluation of on-farm irrigation scheduling with minimum field data. M. Sc. Thesis. International Institute for Geo-information Science and Earth Observation. Enschede. the Netherlands. ITC.
Droogers. P., Bastiaanssen, W. G. M., Beyazgul, M., Kayam, Y., Kite, G. W. and Murray-Rust, H. 2000. Distributed agro-hydrological modeling of an irrigation system in western Turkey. Agric. Water Manag.  43, 183-202.
Faria, R. T., Madramootoo, C. A., Boisvert, J. and Prasher, S. O. 1992. A comparison of the versatile soil moisture budjet and SWACROP models in Brazil. The American Society of Agricultural Engineers Charlohe. June. 21-24. North Carolina.
Fechter, J., Allison, B. E., Sivalcumar, M. V. K., Van Der Ploeg, R.R. and  Beley, J. 1991. An evaluation of the SWATRE and CERES-Milet models for southwest Niger. Proceedings of the Niame Workshop IAHS Pub.
Feddes, R. A., Kowalik, P. J. and Zaradny, H. 1978. Simulation of Field Water Use and Crop Yield. Pudoc. Wageningen.
Homaee, M. 1999. Root water uptake under non-uniform transient salinity and water stress. Ph.D. Thesis. Wageningen  Agricultural University.
Jury, W. A., Gardner, W. R. and Gardner, W. H. 1991. Soil Physics. Fifth edition. Wiley. N. Y.
Keith, L. and Green, R. E. 1991. Statistical and graphical methods for evaluating solute transport models: Overview and application. J.  Cont. Hydrol. 7, 51-73.
Kiani, A. R., Asadi, M. E., Homaee, M. and Mirlatifi, M. 2005. Wheat production function under salinity and water stress conditions. Proceedings of MTERM International Conference. June 6-10. AIT. Thailand.
Loague, K. and Green, R. E. 1991. Statistical and graphical methods for evaluating solute transport models: overview and application. J. Cont. Hydrol. 7, 51-73.
Maas, E. V. and Hoffman, G. J. 1977. Crop salt tolerance current assessment. J. Irrig. Drain. Eng. 103(2): 115-134.
Minhas, P. S. and Gupta, R. K. 1993. Conjunctive use of saline and non saline waters. III. Validation of applications of transient model for wheat. Agric. Water Manag. 23, 149-160.
Molz, F. J. 1981. Models of water transport in the soil - plant system. A review. Water Resour. Res. 17(5): 1245-1260.
Richards, L. A. 1931. Capillary conduction of liquids in porous mediums. Physics. 1, 318-333.
Ruiz, M. E. and Utset, A. 2003. Models for predicting water use and crop yields. A Cuba experience. Available on the: http://users.ictp.it/~pub-off/Lectures/inso18/28 Ruiz.pdf.
Singh, R. 2003. Water productivity of irrigated crops in Sirsa distraction, India. Interaction of remote sensing crop and soil models and GIS. In: Van Dam, J. C. and Malik, R. S. (Eds.). WATRO Final Report. ISBN 90-6464-864-6.
Smith, M., 1992. Cropwat: A computer program for irrigation planning and management. FAO Irrig. Drain. paper No. 46.
Taylor, S. A. and Ashcroft, G. M, 1972. Physical Edaphology. Freeman and Co. San Francisco. California.
Van Dam, J. C., Huygen, J., Wesseling, J. G., Feddes, R. A., Kabat, P., Van Walsum, P. E. V., Groenendijk, P. and Van Diepen, C. A. 1997. Theory of SWAP, version 2. Simulation of water flow, solute transported plant growth in the soil-water-atmosphere-plant environment. Report No.71. Dept.  Water Resour. Wageningen Agricultural University.
Van Genuchten, M. Th. 1980. A closed form equation for predicting the hydraulic conductivity of unsaturated soils. Soil Sci. Soc. Am. J. 44, 892-898.
Van Genuchten, M. Th., Leij, F. J. and Yates, S.R., 1991. The RETC code for quantifying the hydraulic functions of unsaturated soils. Report No. EPA/600/2-91/065. Ada. Okla. U.S. Environmental Protection Agency. Kerr, R. S. Environmental Research Laboratory.    
Wenkert, W. 1983. Water Transport and Balance Within the Plant: An overview.P.137-172. In: Taylor, H. M. (Eds.). Limitations to Efficient Water Use in Crop Production. ASA, CSSA, and SSSA, Madison, WI.
Wesseling, J. G., 1991. Meerjarige simulaties van grondwateronttrekking voor verschillende bodemprofielen, grondwatertrappen en gewassen met het model SWATRE. Report No. 152. Winald Staring Centre. Wageningen.
Wyseure, G. C. L., Sanmuganathan, K. and  O’Callaghan, J. R. 1994. Use of simulation for combining rainfed and irrigated sugarcane production in dry zone of Sri Lanka. Electron Agri. 11, 323-335.