Document Type : Research Paper
Author
Research Associate Professor, Agricultural Engineering Research Institute (AERI); Agricultural Research, Education, and Extension Organization (AREEO), Karaj, Iran.
Abstract
Water Utility Index (WUI), first introduced by D. White (1958), is defined as one kg of crop produced per one cubic meter of water evpotranspired. This concept was later replaced with the more inclusive one of ‘water productivity’ (WP). The objective behind this latter concept was to provide a measure for interpreting the results of field experiments of water consumption used in making proper provisions for irrigation management, detecting opportunities for water saving and enhancing water productivity, and developing water allocation decision-making support systems. In order to address the water crisis at the national level, the present article presents a detailed definition of the index and the challenges facing its application to develop realistic water saving measures. It is claimed that evaluations solely based on the WP Index, in which the water applied (or, water withdrawn) is the denominator (WPAW), are to some extent misleading. It is argued that the index does not represent real amounts of water saved or effectively used, especially when it comes to the assessment of the so-called ‘water-saving irrigation systems (e.g., pressurized irrigation). To overcome this inadequacy, it is initially proposed that the ET-based WP (i.e., WPET), rather than the plain WP index, should be used for this purpose. In a second stage of the study, a simple computational methodology is developed that is based on the currently available and cost-effective data on ETc and crop yields across the nation (as reported in the national document on water or in the statistical reports on agriculture). As an illustration, the data available on the Karkheh River Basin and the WPET values measured for the major crops of wheat, barely, alfalfa, potato, silage maize, clover, grain maize, sugar beet, onion, tomato, cucumber, and watermelon grown in the basin are computed to be 1.32, 1.49, 1.22, 5.74, 7.93, 1.73, 1.37, 6.17, 6.61, 8.24, 5.07, 6.94, and 2.05 kg/m3, respectively, which are then used to calculate the average value of 2.05 kg/m3 for the whole basin. Finally, WP values reported in the literature and measured using the conventional filed methods (i.e., WPAW) for the above crops grown both in the study basin and across the state are used to derive a proper regression relation between WPET and WPAW, which exhibits a satisfactory goodness of fit (R2=0.96). Using this relation, the average value of WPAW for the basin is obtained to be about 1.20 kg/m3, which is consistent with the values reported elsewhere. Based on the above observations, application of the proposed method as a low-cost and reasonably accurate one is recommended for the estimation of WPET and, thereby, WPAW.
Keywords
- حیدری، ن. 1390.تعیین و ارزیابی شاخص کارایی مصرف آب محصولات زراعی تحت مدیریت کشاورزان در کشور. مجله مدیریت آب و آبیاری. دوره 1، شماره 2، پائیز 1390، صفحات 57-43.
- حیدری ن. 1395. تعیین و ارزیابی شاخص کارائی مصرف آب پتانسیل و مزیت نسبی کشت محصولات زراعی و باغی عمده فاریاب در حوضه آبریز کرخه. گزارش پژوهشی، موسسه تحقیقات فنی و مهندسی کشاورزی، شماره فروست 48483، 160صفحه.
- حیدری، ن.، اسلامی، ا.، قدمی، ع.، کانونی، ا.، اسدی، م.ا.، خواجه عبداللهی، م.ح. 1384. تعیین کارایی مصرف آب محصولات زراعی مناطق مختلف کشور (مناطق کرمان، همدان، مغان، گلستان، و خوزستان). گزارش پژوهشی موسسه تحقیقات فنی و مهندسی کشاورزی، شماره فروست 988/84، 113 صفحه.
- عباسی، ف.، عباسی، ن.، و توکلی، ع.ر. 1396. بهره وری آب در بخش کشاورزی: چالشها و چشم اندازها. یادداشت تحلیلی، نشریه آب و توسعه پایدار، جلد 4، شماره 1، ص. 144-141.
- عباسی، ف.، ناصری، ا.، سهراب، ف.، باغانی، ج.، عباسی، ن.، و اکبری، م. 1394، ارتقاء بهرهوری مصرف آب. مجموعه یادداشتهای فنی. موسسه تحقیقات فنی و مهندسی کشاورزی، 69 صفحه.
- کاوه، ف. و حسینی ابری، س. ع. 1388. افزایش بهره وری آب در کشاورزی آبی. مجموعه مقالات دوازدهمین همایش کمیته ملی آبیاری و زهکشی ایران، مدیریت آبیاری در ایران: چالشها و چشم اندازها. 6-5 اسفند 1388، تهران.
- کریمی، م. و جلینی، م. 1396. بررسی شاخصهای بهرهوری آب کشاورزی در محصولات مهم زراعی، مطالعه موردی دشت مشهد. یادداشت فنی، نشریه آب و توسعه پایدار، شماره 1، تابستان 1396، ص. 138-133.
- مهتدی، م. الباجی، م.، دوست محمدی م. م.1392 بررسی بهره وری آب سه محصول زراعی جو، گندم، و یونجه در استان خوزستان به تفکیک شهرستان. مجموعه مقالات چهارمین همایش ملی مدیریت شبکههای آبیاری و زهکشی، دانشگاه شهید چمران اهواز، دانشکده مهندسی علوم آب، 6 الی 8 اسفند 1392، صفحات 936-929.
- Bessembinder, J.J.E., Leffelaar, P.A, Dhindwal, A.S., Ponsioen, T.C.2005. Which crop and which drop, and the scope for improvement of water productivity. Agricultural Water Management. 73 (2005). 113–130.
- Cheraghi, S.A M., Heydari, N. Qadir, M. and Oweis, T. 2010. Improving crop growth and water productivity on salt-affected soils in the Lower Karkheh River Basin. Research report, ISBN: 92-9127-240-X, ICARDA, Aleppo, Syria, 66 pp.
- De Wit, C.T. 1958. Transpiration and Crop Yields. Modeling Nr. 59. Instituut voor Biologisch en Scheikundig, Onderzoek van landbouwgewassen. Wageningen.
- Faramarzi, M., Yang H., Schulin R., Abbaspour K. 2010. Modeling wheat yield and crop water productivity in Iran: Implications of agricultural water management for wheat production. Agricultural Water Management 97 (2010) 1861–1875.
- Moayeri, M., Dehghanisanij, H., Farhad Nato, A., Siadat, H., Abbasi, F. and Oweis, T. 2012. Assessment and improvement of wheat and maize in water productivities in Lower Part of KRB. CPWF Karkheh River Basin Research Report 9. ICARDA, Aleppo, Syria. x + 103 pp.
- Molden D. 1997. Accounting for water use and productivity. In: SWIM Paper 1, IIMI, and Colombo.
- Murray-Rust, H, Droogers, P., Heydari, N. 2004. Water for the future: Linking irrigation and water management in the Zayandeh Rud basin, Iran, Final report, IWMI.
- Perry, C.2007. Efficient irrigation; inefficient communication; flawed recommendations. Irrigation and Drainage, vol. 56. Wiley Inter science, pp. 367–378.
- Perry, C. 2011. Accounting for water use: Terminology and implications for saving water and increasing production Agricultural Water Management 98, pp. 1840–1846.
- Perry, C., Steduto, P., Karajeh, F. 2017. Does improved irrigation technology save water?: A review of the evidence. Book, Food and Agriculture Organization of United Nations, CAIRO, pp. 1-57.
- Seckler, D, Molden, D, Barker, R.1999. Water scarcity in the twenty first century, Water Brief 1. IWMI. Colombo Sri Lanka.
- Singh, R.2005. Water productivity analysis from field to regional scale: Integration of crop and soil modeling, remote sensing, and geographical information. Ph.D. Dissertation, Wageningen Univ., Wageningen, The Netherlands.
- Turral, H., Cook, S., Gichuki, F. 2006. Water productivity assessment: Measuring and mapping methodologies. Basin Focal Project. Working Paper no. 2. Challenge Program on Water and Food.
- Willardson, L.S., Allen, R.G., Frederiksen, H. 1994. Eliminating irrigation efficiencies. In: USCID 13th Technical Conference, Denver, Colorado, 19–22 October, 15 pp.