Project National Team in Engr. A. Anagholi - National Salinity Research Center, Yazd Dr Z. Shoaei - Director General, Dept of Intl Engr. A. Abayani - Khuzestan Agricultural & Scientific & Research Affairs, AREO, and Focal Natural Resources Research Center, Ahwaz Person for CPWF projects in Engr. A.R. Tavakoli - Researcher, DARI, Basin (KRB), Tehran Kermanshah Dr A. Javadi - Director, Agricultural Engg Engr. H. Asadi - Research staff, Seed & Plant Research Institute (AERI), and National Improvement Research Institute, Agricultural About ICARDA and the CGIAR Coordinator of Water Productivity Project, Economics, Karaj Karaj Engr. A. Ayeneh - Seed & Plant Improvement Res. Dr M.H. Davoudi - Director, Soil Conservation & Div., Khuzestan Ag. Research Center, Ahwaz Established in 1977, the International Center for Agricultural Research Watershed Mgmt Research Institute, Tehran in the Dry Areas (ICARDA) is one of 15 centers supported by the Engr. F. Mazraeh - Extension Div. of Azadegan Dr S.A.M. Cheraghi - Director, National Salinity and Sorkheh Agricultural Mgmt Dept, CGIAR. ICARDA’s mission is to improve the welfare of poor people Research Center, and Principal Investigator of Khuzestan Agricultural Organization, Ahwaz through research and training in dry areas of the developing world, Water Productivity Project, Yazd Engr. M. Ghamarinejad - Head of Agricultural by increasing the production, productivity and nutritional quality of Dr A. Ghaffari - Director, Dryland Agricultural Service Center of Sorkheh Agricultural Mgmt food, while preserving and enhancing the natural resource base. Research Institute, Maragheh Dept, Khuzestan Jihad-e-Agricultural ICARDA serves the entire developing world for the improvement of lentil, Dr F. Abbasi - Deputy Director Assistant Organization, barley and faba bean; all dry-area developing countries for the improvement of Coordinator of Water Productivity Project, on-farm water-use efficiency, rangeland and small-ruminant production; and the AERI, Karaj Project International Team Central and West Asia and North Africa (CWANA) region for the improvement of Dr N. Heydari - CPWF Karkheh Basin Coordinator, bread and durum wheats, chickpea, pasture and forage legumes, and farming Irrigation & Drainage Dept, AERI, Karaj Dr. T.Oweis - Director, Integrated Water & Land systems. ICARDA’s research provides global benefits of poverty alleviation Dr H. Dehghanisanij - Irrigation & Drainage Dept, Management Program, & Project Manager of through productivity improvements integrated with sustainable natural-resource AERI, Karaj Water Productivity, International Center for management practices. ICARDA meets this challenge through research, train- Dr M. Akbari - Irrigation & Drainage Dept, AERI, Agricultural Research in the Dry Areas - ICAR- ing, and dissemination of information in partnership with the national, regional Karaj DA, Aleppo, Syria and international agricultural research and development systems. Dr S. Ashrafi - Irrigation & Drainage Dept, AERI, Dr. H. Farahani - Integrated Water & Land Karaj Management Program, & Assist. Project Engr. A. Keshavarz - Senior Irrigation & Water Manager of Water Productivity, ICARDA, The Consultative Group on International Agricultural Research Mgmt Scientist, Principal Investigator and for- Aleppo (CGIAR) is a strategic alliance of countries, international and regional mer National Coordinator of Water Dr. H. Siadat - Integrated Water & Land organizations, and private foundations supporting 15 international Productivity Project, Tehran Management Program, & agricultural Centers that work with national agricultural research sys- Dr S.A. Asadollahi - Director General and Under Facilitator/Coordinator of Water Productivity, tems and civil society organizations including the private sector. The Secretary of Iranian National Committee on ICARDA, Tehran alliance mobilizes agricultural science to reduce poverty, foster Irrigation & Drainage, Ministry of Energy, Dr. A. Bruggeman - Integrated Water & Land human well being, promote agricultural growth and protect the environment. Tehran Management Program, ICARDA, Aleppo The CGIAR generates global public goods that are available to all. Dr E. Pazira - Professor, Azad Islamic University, Dr. M. Qadir- Integrated Water & Land The World Bank, the Food and Agriculture Organization of the United Nations Research Science Division, Tehran Management Program, ICARDA, Aleppo (FAO), the United Nations Development Programme (UNDP), and the Engr. M. Moayeri - Director, Safi Abad Research Dr. K. Shideed - Director, Social, Economic & International Fund for Agricultural Development (IFAD) are cosponsors of the Station, Dezful Policy Rsrch.Prog., & PI of Water Productivity CGIAR. The World Bank provides the CGIAR with a System Office in Washington, Engr. B. Hessari - Irrigation Researcher, AERI project, ICARDA, Aleppo DC. A Science Council, with its Secretariat at FAO in Rome, assists the System in branch in West Azarbaijan Ag. Research Dr. E. De Pauw - Head, Geographic Info. Systs. the development of its research program. Center, Uromieh Unit, & PI of Water Productivity project, ICAR- Engr. S. Absalan - Agricultural Engg Research Div, DA, Aleppo Khuzestan Ag. Research Center, Ahwaz Dr. J. Anthofer - Integrated Water & Land Engr. E. Dehghan - Agricultural Engg Research Management Program, ICARDA, Aleppo Div, Khuzestan Ag. Research Center, Ahwaz Dr. M. Pala - Integrated Water & Land Engr. A.F. Nato - Research Staff, Safi Abad Ag. Management Program, ICARDA, Aleppo Research Center, Dezful Dr. T. Hsiao - Prof., University of California at Davis, Engr. Y. Hasheminejhad - National Salinity & PI of Water Productivity project, Davis, Research Center, Yazd California, USA Engr. G.H. Ranjbar - National Salinity Research Dr. A. Qureshi - International Water Management Center, Yazd Institute, & PI of Water Productivity project, Engr. M.H. Rahimian - National Salinity Research Karaj Center, Yazd ICARDA-01/500/Salhani/January 2008 Improving On-farm Agricultural Water Productivity in the Karkheh River Basin (CPWF Project no. 8)

Research Report no. 1

A Compendium of Review Papers

Edited by: T. Oweis, H. Farhani, M. Qadir, J. Anthofer, H. Siadat, F. Abbasi and A. Bruggeman

International Center for Agricultural Research Agricultural Research and Education in the Dry Areas Organization Copyright © 2008 ICARDA (International Center for Agricultural Research in the Dry Areas)

All rights reserved.

ICARDA encourages fair use of this material for non-commercial purposes, with proper citation.

Citation: T. Oweis, H. Farahani, M. Qadir, J. Anthofer, H. Siadat, F. Abbasi and A. Bruggeman (eds). 2008. Improving On-farm Agricultural Water Productivity in the Karkheh River Basin. Research Report no. 1: A Compendium of Review Papers. ICARDA, Aleppo, Syria. iv+103 pp.

ISBN: 92-9127-205-9

International Center for Agricultural Research in the Dry Areas (ICARDA) P.O. Box 5466, Aleppo, Syria. Tel: (963-21) 2213433 Fax: (963-21) 2213490 E-mail: [email protected] Website: www.icarda.org

The views expressed are those of the authors, and not necessarily those of ICARDA. Where trade names are used, it does not imply endorsement of, or discrimination against, any product by the Center. Maps have been used to support research data, and are not intended to show political boundaries.

ACKNOWLEDGMENTS

We acknowledge with thanks the funding and research support of the CGIAR Challenge Program on Water and Food in the research on which this publication is based.

Cover design: George Chouha

ii Contents

Introduction 1

Chapter I – Agricultural Water Productivity in Karkheh River Basin 3 Hamid Farahani and Theib Oweis Introduction 5 Water Productivity in the Karkheh River Basin 7 Background and Justification 7 Upper Karkheh River Basin 9 Lower Karkheh River Basin 9 Water Productivity – Definition and Analysis 12 WP of Multi-Sector Land Use Systems 14 Methodology for Assessment/ Diagnosis of WP in Karkheh 15 Concluding Remarks & Future Work 16 References 17

Chapter II – Supplemental Irrigation in Iran 19 Ali Reza Tavakoli, Abdolmajid Liaghat, Shahram Ashrafi and Fariborz Abbasi Introduction 21 Supplemental irrigation in WANA 21 Supplemental irrigation in Iran 25 Climate 25 26 Water productivity (WP) concept 27 Previous supplemental irrigation research 27 Optimization of supplemental irrigation 36 Conclusions 36 References 38

Chapter III – Overview of Crop Water Productivity in Irrigated Agriculture in Lower Karkheh River Basin 43 Hossein Dehghanisanij and Mansour Moayeri Introduction 45 Water and land resource and productivity 46 Challenges and opportunities for improving WP 52 References 54 Chapter IV - Overview of Soil and Water Resources and Salinity in Lower Karkheh River Basin 57 Nader Heydari and Seyed Ali Mohammad Cheraghi Introduction 59 The Khuzestan Environment 60 Climate and Soils 60 Surface Water Resources 61 Ground Water Resources 61 The Khuzestan Water & Power Authority (KWPA) 61 Challenges in the soil & water development of the 63 Soil and water salinity in Iran 63 Extent and types of saline soils in Iran 63 Causes of soil salinization in Iran 65 Salinity research and management in Iran 65 Salinity in Karkheh River Basin (KRB) 67 Dasht-e Azadegan Plain 71 Salinity in the Dasht-e Azadegan 73 Conclusions and Recommendations 76 References 79

Chapter V – Causes and Management of Salt-prone Land Degradation in Lower Karkheh River Basin 81 S.A.M. Cheraghi, Y. Hasheminejhad, and N. Heydari Introduction 83 Major causes of in the lower Karkheh basin 85 High table 86 Salt containing layers 86 Inadequate drainage facilities 87 High evaporation 87 Salt intrusion by wind 88 Sediment transport in the flood periods 88 Past research and development 88 Future research and development 90 References 91

iv INTRODUCTION • Options for sustainable improvement of water productivity in irrigated and rain- The world water resources are under fed systems increasing stress as the human population • Farmers’ adoption of the new recom- and water demand per capita increases. mendations and technologies These problems are not new, but are now • Progressive policies and suitable institu- becoming more widespread and their tional arrangements impacts more devastating. This has provid- • Capacity building of NARS and commu- ed additional impetus for the search for nity leaders solutions to problems arising from the mis- • Assessment of water productivity and match between demand and supply in institutional and policy structures terms of water quantity, quality and timing. Increasing water productivity has been The work is conducted in partnership identified as one of the global challenges between two CGIAR centers (ICARDA and that require urgent attention. IWMI), the main umbrella NARS in Iran, the Agricultural Research and Education Water in the Karkheh River Basin (KRB) is Organization (AREO), and its research insti- limited and becoming scarce as popula- tutes such as the Agricultural Engineering tion and demand are increasing. The pro- Research Institute (AERI), Seed and Plant ductivity of rain-fed agriculture is low; con- Improvement Institute (SPII), and Dry land ventional is poor; Agriculture Research Institute (DARI), cropping systems are sub-optimal; and University of California, Davis, USA, and policies and institutions have room for most importantly, the farmers and exten- improvement. However, Iran’s agricultural sion staff in the basin. The project is for over strategy identifies water productivity four years (starting in 2004), with over one improvement as a top priority. The KRB third of its budget contributed by AREO. reflects in many aspects the problems of The partners’ commitments of sizable water management in other basins in the matching funds and the strong presence region. Accordingly, it is intended to link of ICARDA and IWMI in Iran and the wider the work in KRB with the and region have ensured a cost-effective and Amu Darya river basins. low-risk project.

The aim of this CP project, Improving On- This report contains five chapters, collec- Farm Agricultural Water Productivity in the tively providing background information Karkheh River Basin (KRB), (PROJECT REFER- and review of past research at Karkheh ENCE NO: PN8) is to help the resource- with some relevant information from across poor communities in the basin to sustain- Iran. This is the first of a series of research ably improve their income and livelihoods. reports on Karkheh, summarizing the avail- The specific objectives are to improve farm able data and information on natural and basin water productivity and the sus- resources and livelihoods and identifying tainable management of the natural the gaps which need to be addressed in resource base; develop appropriate poli- the present as well as future projects. The cies and institutions; and enhance the production of the chapters has been facili- capacity of National Agricultural Research tated by ICARDA through close coopera- Services (NARS). tion with NARS of Iran. The chapters stress the main challenges to improving WP and Means and activities needed to achieve are authored by NARS scientists who have this goal include: first-hand knowledge of the issues and on-

1 going on-farm research experiments at and irrigated systems in addition to elabo- Karkheh. rating on salinity and water-logging prob- lems. The data presented and the opinions Chapter I provides a summary background offered are the sole responsibility of the of, and justification for, the project and authors. The synthesis provided in this briefly discusses WP issues across the wider report should make a valuable contribution basin. Chapters II to V provide a more in- to the ongoing development of under- depth review of past agricultural and standing of the intricacies of the efficient water research for the dominant rain-fed use of water at Karkheh River Basin.

2 CHAPTER I Agricultural Water Productivity in Karkheh River Basin

Hamid Farahani1 and Theib Oweis2

1Irrigation & Water Management Specialist, Integrated Water & Land Management Program, International Center for Agricultural Research in the Dry Areas (ICARDA), Aleppo, Syria 2Director, Integrated Water & Land Management Program, ICARDA, Aleppo, Syria

3

INTRODUCTION perspective allows a greater clarity at the importance of the institutional interventions The world is currently facing the challenge regarding how planning, policies, rights, of producing more food with less water. regulations, monitoring, and water-user Increasing water productivity (WP) is global organizations need to be designed and challenge that require urgent attention. implemented to enhance the effective This challenge stretches across agricultural functioning of organizations at basin and disciplines and sectors and certainly system levels as well as at the level of indi- requires the concerted action of all stake- vidual user or users. Additionally, environ- holders: farmers, water managers, hydrolo- mental and ecological issues related to gists, agronomists, water resources special- water can also be more properly looked at ists, engineers, socio-economists, and poli- from a basin perspective. cy makers. The understanding of how effectively water is acquired and man- In spite of the above argument, it is of aged and how efficiently water is used is utmost importance to recognize that no the key to effectively tackle the challenge effective basin-wide assessment can be of improving WP. formulated or constructed in the absence of sound and spatially and temporally To improve the livelihoods of the large agri- dense data from the underlying lower cultural population in the developing scales of field and farm. It is thus at this world, the development and adoption of lower, but necessary level of complexity technologies and strategies that facilitate and integration, where the Karkheh River the improving of agricultural production Basin (KRB, shown in Fig. 1) project initiated per unit of water is becoming increasingly its research activities in the target areas of important. Research shows that substantial the project, with subsequent linkages and and sustainable improvements in water out-scaling to be made at the basin level. productivity is attainable, but can be best The challenge is how to out-scale the achieved through community-based inte- results to other areas in the basin and the grated natural resource management country and how to up-scale as policy approaches. In the past, focus on improv- options for local, regional, and national ini- ing WP has primarily been on plant- and tiatives. The use of modeling, GIS, and field-scale, while recently water productivi- remote sensing technologies is promoted ty at higher levels such as farm-, project-, to simulate and estimate first-level out-scal- basin- and regional-scales is increasingly ing of the potential impact at higher scales used. with the goal of effective farmers' adop- tion and wider dissemination through out- Examining water use from a basin perspec- reach, enabled institutions and effective tive means that not only water supply and policies. demand for all users are looked at, but also at institutional issues involved in the The Karkheh River Basin research project is provision of services. At the basin-scale, the community-based with participation of interaction between the upstream and farmers, community leaders, local institu- downstream uses and users of water tions and policy makers. The belief is that becomes more evident and raising acute the direct interaction between the project equity issues. Deterioration of water quality, and the beneficiaries will produce the opti- either from agricultural or urban-industrial mum results. The hypothesis of this project is complexes, that reduces the value and that water productivity in the KRB could be utility of water to downstream users, is substantially increased by improving on- another basin-wide water issue. The basin farm water management, introducing new

5

Fig. 1. Map of Iran showing the Karkheh River Basin (KRB) in the west. crop varieties, adjusting cropping patterns, Four benchmark sites are selected under optimizing supplemental, deficit, and full rainfed and irrigated conditions. irrigation and integrating appropriate agro- Experiments and demonstrations are con- nomic practices in the crop production sys- ducted under researcher- and farmer- tem with suitable institutional arrangements managed conditions to develop, test, and policies. It is believed that the key to apply, and improve the adoption of better the realization of this hypothesis is the water management, agronomic practices, involvement and participation of farmers and technology options. An integrated and local communities as well as the full approach to developing efficient systems is cooperation of the official organizations used. Socioeconomics forms an integral and authorities responsible for water and part of the project to ensure a problem- agricultural development of the basin. solving approach and a higher adoption Therefore, the project has made substan- potential. Special attention is given to the tial efforts to provide the necessary frame- role of women in agricultural water man- work and encourage participation of these agement and use. Policies and institutional target groups at all stages of the project structures are examined and recommen- implementation. There are also coordinat- dations communicated. ed activities with other CP projects (PN24 Livelihood Resilience of ICARDA and the The consequences of the outputs at the Basin Focal Point of IWMI) in the Karkheh basin level will be studied and projections basin in terms of logistics and scientific made available. Existing policies and insti- aims so as to increase the use-efficiency of tutions will also be explored in two other the available resources. relevant basins, the Euphrates and Amu

6 Darya, with the help of respective national and its people's livelihoods clearly depends experts. on more holistic, basin-wide management and monitoring of natural resources— The objective of this chapter is to provide water, soil, vegetation and livestock. The an overview of the some important water KRB project will contribute in two ways by: productivity (WP) issues across the Karkheh 1) Helping build a better scientific under- river basin and at varying scales. standing of the human and biophysical Subsequent chapters offer more in-depth dynamics of the basin, and 2) Designing examination of WP issues at rainfed areas practical tools, guidelines and technologies above the and fresh and for farmers, policymakers and scientists. saline irrigated areas below the dam. The Karkheh River Basin is one of the most WATER PRODUCTIVITY IN THE important agricultural zones of Iran and among the areas suffering from low water KARKHEH RIVER BASIN productivity. The KRB has an area of 50,764 km2, a total of five sub-basins covering Background and Justification parts of 7 provinces (Figs. 2), a population of approximately 4 million, with 67% rural Increasing water scarcity and frequent and a per capita income from agriculture droughts in the region have attracted of US$230. Annual rainfall ranges from attention to the necessity of improving about 150 mm in the south to 700 mm in water productivity. While more than 90% of the north, with an average of 490 mm of the water resources of Iran are used for which an estimated 325 m (or 66%) is con- agriculture, the overall efficiency is about sumed by evapotranspiration. The climate 37% (Keshavarz et al., 2000). Accordingly, is mainly semi-arid, interspersed with arid the third National Development Plan of portions. Iran identified increasing water productivity in agriculture as a top priority. Total developed water resources are over 8 billion m3 (after completion of the The Karkheh River Basin is, most notably, Karkheh dam) and irrigation water con- the eastern flank of the "cradle of civiliza- sumption is estimated.at 3.9 billion m3/year tion" (ancient Mesopotamia) and a bound- (more than 60% is surface water). ary between the Arab and Persian cul- Groundwater consumption and use is tures. This major river system of western Iran about 1.65 billion m3/year; with agriculture, has unique agricultural and hydrological drinking water and industry using up 87, 12, aspects and also has much in common and 1%, respectively. The total irrigated with other catchments around the world area is 1,100 km2, with planned expansion such as rural poverty and land degrada- to 3,400 km2. Major crops such as wheat tion, low water and agricultural productivi- and barley are grown over 76% of the ty, a dry climate, and growing upstream- area, pulses account for a coverage of downstream competition for water. 23% of the area, and 1% of it goes for rais- ing forages, orchards, vegetables, and oil Changes in land use patterns in recent seeds. Area suitable for rainfed agriculture decades, especially overgrazing and con- is 8,940 km2. The main institutional arrange- version of natural pastures to rainfed crop- ment for managing water is the Ministry of ping, have taken a heavy toll. Ninety per- Power, which is responsible for water cent of the upper watershed's rangelands development and allocation. Detailed and 70% of its forests have been signifi- background on KRB characteristics can be cantly degraded. The future of the KRB found elsewhere (e.g., Keshavarz, 2005).

7 Fig. 2. Gradients of precipitation (top left), temperature (top right), and potential ET (bottom left) across Karkheh River Basin, also shown are main sub-basins and rivers (bottom right). (prepared by Soil Conservation and Watershed Management Research Institute, Tehran, Iran).

8 There are two major agricultural produc- ty ranges from 0.3 to 0.5 kg m-3; these pro- tion systems in this basin. One is the rainfed ductivity levels achieved an income of less production upstream of the newly built than US $50 ha-1 at the beginning of the Karkheh reservoir and the other is the fully project. The upper catchments are irrigated and thus intensified cropping sys- among the most suitable rainfed zones of tem downstream of the dam (Fig. 3). the country, with long-term annual precipi- Livestock is well integrated into most rain- tation of 350-500 mm. However, due to fed farming systems that includes cattle, fluctuations in rainfall both within and sheep and goats. The rainfed areas are between seasons, as well as the variations well established and cover most of the in agro-climatic conditions and lack of agricultural lands in the upper catchments, appropriate management measures the while in the lower catchments; irrigated productivity is well below potential. areas were limited before the building of In the upper rainfed areas the growing the Karkheh dam. However, plans for season is relatively short and yields of rain- expansion are now underway. fed cereals are generally lower than that expected where rainfall exceeds 400 mm. In the upper catchments, fully irrigated One cause is the delay in the early season summer systems cover about 250,000 rainfall that results in late sowing, which hectares. Throughout the basin, there are exposes the crop to cold and frost dam- about one million hectares of irrigable age following sowing. The result is a poor lands (JAMAB Consulting Engineers, 1991, stand of the crop that cannot be compen- and Moemeni, 2003). Therefore, future sated by rainfall later in the season, as expansion in irrigated land is expected. In observed in research by Dryland the upper sub-basins, the expansion will be Agriculture Research Institute (DARI, in both full and supplemental irrigation, Maragheh, Iran) and ICARDA in other rain- while in the lower sub-basin the increase fed areas of Iran. One potential solution is will be in full irrigation. Water Productivity to use supplemental irrigation (SI) to assist (WP) in these areas is also very low, not early planting. This practice has shown only compared to its potential but also impressive results in increasing crop water considering other river basins in Iran. productivity in similar areas of Iran, Syria, Overall grain WP in the basin is estimated Morocco, and Turkey (e.g., see DARI annu- at 0.4 kg m-3. al reports, 1999-02; Tavakoli et al., 2005). Irrigation water availability, conveyance Upper Karkheh River Basin mechanism, and cost are the main con- straints to supplemental irrigation. The KRB In the upper catchments, rainfed farming project has teamed up with scientists from covers most of the land but limited supple- DARI to test various supplemental and mental and full irrigation systems are also deficit irrigation strategies and improved present where water is available (as shown agronomic practices on farmers' fields to by the contrasting environments in Fig. 4). enhance WP in this area (see review in The cropping systems in the rainfed areas Chapter II). cover a total of nearly 894,000 ha and are predominantly cereals in rotation with Lower Karkheh River Basin legumes. Wheat, barley, and chickpea occupy 53%, 23%, and 22% of the area, The downstream part of the basin stretches respectively. The average grain production from the Karkheh dam in the north more per unit area is rather low: 920 kg ha-1 for than 100 km southward, where the Karkheh wheat, 950 kg ha-1 for barley, and about River discharges into the marshlands of 500 kg ha-1 for chickpeas. Water productivi- Hoor-al- Azim. A number of sub-basins in

9 Fig. 3. Rainfed agriculture in upper KRB (left) and irrigated farming in lower KRB (right) are the dominant agricultural production systems. the command area, including Dasht stream is predominantly irrigated (now Abbas, Evan, Dusaif, Ardyez, and Bageh, about 111,000 ha), with annual rainfall as well as some in the lower plain, are ranging from 300 mm in the north to 100 planned for over 300,000 hectares expan- mm in the south. Soils are mostly young sion of irrigation systems including new irri- river deposits of fine texture with little profile gation and drainage networks (Fig. 5). In development and medium to low infiltra- the lower KRB (especially immediately tion rates. Salinity of topsoil fluctuates dur- below Karkheh dam), water availability is ing the season and, generally, increases improving due to installation of large scale towards the south. The river water quality is irrigation and drainage networks. However, good, though it varies both seasonally and full scale delivery of irrigation water from along the river. Karkheh dam is at least a few years away due to slow pace of construction of the The lower KRB area is suitable for a wide distribution network and in some cases, range of crops. Presently, wheat, maize, lack of funding. Agriculture in the down- alfalfa, and off-season vegetable crops

Fig. 4. Contrasting wetter and dryer environments in the upper Karkheh as a result of surface water availability.

10 are the most popular. However, crop water problem. Before the construction of the productivity and irrigation and con- dam, seasonal floods were the biggest veyance efficiencies (see example in Fig. source of water for leaching salts. Farmers 6) are low and land and water resources were growing wheat and barley using river are at risk of quality degradation. Average water or flood water (in the past) but the irrigated cereal yields are still relatively low yields were low (1-1.5 t/ha) and at times at 2300 kg/ha and water productivity val- failures occurred. There were no significant ues between 0.5 and 0.6 kg/m3. Values reclamation measures practiced by farm- reported for the overall irrigation efficiency ers. As part of the KRB project, the National of the traditional networks in Dasht Salinity Research Center (NSRC, Yazd, Iran) Azadegan (southern areas of the lower and the provincial Agricultural Research KRB) range around 14-23% (Mir-abolghase- Center are conducting on-farm salt-toler- mi, 1994). In the neighboring basin of the ant and water and salinity management Dez River, in consolidated fields of the experiments in this area (see review in modern networks efficiencies are little bet- Chapters IV & V). ter at 32-37% (Fatemi, et al, 1994). Water productivities for the annual crops such as wheat and barley are less than 0.5 kg m-3. The large amount of water loss during con- veyance and field application has greatly aggravated resource degradation caus- ing, among other problems, drainage and salinity in the downstream sub-basins and lowland areas. Obviously, with the present management practices, such threats will expand in the future and their impacts will be wider. The KRB project has selected a large irrigated area (Sorkheh) just below the dam and researchers from Agricultural Engineering Research Institute (AERI, Karaj, Iran) and its research stations (Safiabad, Dezful, Iran) are leading extensive on-farm irrigation management experiments to assess and improve WP in the area (see review in Chapter III).

The salt-affected lands and wetlands are the main features of the downstream of the lower Karkheh Sub-Basin. Soil salinity is highly variable in the region with electrical conductivity (EC) ranging from about 2 dS/m to well over 100 dS/m. The major causes of salinity and water logging (Fig. 7) are high water tables (1 to 3 m below soil surface), high evaporative demand and saline soil horizons, magnified by poor irri- gation distribution (Fig. 8). The construction of Karkheh dam helped in minimizing flood Fig. 5. Drainage and irrigation canals in the damage, but it has made salinity a major lower KRB.

11 Fig. 6. Example of poor on-farm water conveyance structures and practices: An earthen irri- gation ditch is shown, in which the farmer has cut through its left bank to convey water across the road to the field on the left, also causing other problems such as excess runoff (Sorkheh area, Feb 2007).

WATER PRODUCTIVITY - DEFINITION AND ed. Agricultural output resulting from water ANALYSIS use may be: 1) agricultural or natural vege- tative biomass, 2) nutritional content of var- There are numerous publications on the ious forms of food produced, and 3) eco- concept of WP, its context-sensitivity, and nomic and societal value created in differ- scale-dependency. These are only briefly ent sectors such as agriculture, fisheries, summarized below (and also in subsequent livestock and agro-forestry. There is also chapters) and the interested reader is non-agricultural uses and thus benefits of referred to the recent book on compre- water such as in recreation and maintain- hensive assessment of water management ing ecosystems health and wildlife habitats in agriculture (Molden, 2007) and therein. is of importance. In most cases water is quantified in units of volume (e.g., m3 In the most general sense, productivity is water) that crosses the boundary of the an output-input relationship, a broad con- scale under consideration (e.g. field, farm, cept in agriculture with water productivity irrigation network, a nd basin) or changes encompassing biophysical as well as socio- in the volume stored within system bounds economic aspects of the relation between during the time period of analysis. beneficial outputs from the use of a unit of The basin is the highest order scale for water input. For agricultural water use, the hydrologic flows and physical water man- primary focus is placed on food produc- agement. Agricultural water productivity at tion, therefore water productivity is defined the basin scale is not simply a linear extrap- as food or value output per unit of water olation of the individual system-level agri- consumed, applied, diverted, or degrad- cultural water productivities. A number of tradeoffs exist with allocating water for

12 agriculture versus ecosystems. As a result, The principle purpose of measuring WP is to the water productivity definition that allows identify opportunities to improve the gain comparison across contexts needs to from the use of water. For instance, in crop include multiple uses of water. These are production, the goal of improving yield per best captured in the elusive term value, unit water used is achieved by either which reflects appreciation society holds increasing the productivity per unit con- for biodiversity, ecosystem integrity, habitat sumption of water, reducing the consump- maintenance, aesthetics, cultural impor- tion without decreasing production, or by tance, and goods and services based on reducing both, but at a lower rate for out- hydrologic flows. The water input denomi- put than input water (e.g., in deficit irriga- nator becomes not just the physical deple- tion). In all cases, water productivity quan- tion of water but may include degradation tifies how beneficial water is used in pro- in its quality. ducing goods and services. Water produc-

Fig. 7. Water logged (left) and severe salt build up (right) in irrigated fields in lower KRB (Dash e Azadegan).

Fig. 8. Water logging and non-uniform distribution (left) and poor emergence (right) in saline water irrigated fields in lower KRB (Dash e Azadegan).

13 tivity is scale dependent. At different a host of agricultural sectors and thus scales, water productivity affects different water-related activities, which together stakeholders with different sets of objec- modify pathways of water moving in or out tives. At the farm level, the farmer is inter- of any component sub-system. Differing ested in getting family food secured and land uses across a basin also present other income increased. At basin/regional level, complex activities which interact in ways national food security and health and other than water, including, food, energy, environmental protection are also impor- income or other social exchange. The tant issues to a broader group of stake- result of the above makes the comparisons holders and policy makers. of the value of water depletion for differ- ent benefits and costs difficult. WP of Multi-Sector Land Use Systems The simplest way to compare water pro- Field water management is the lowest ductivity across different enterprises is in scale at which practical water manage- monetary terms, although the full range of ment interventions may be used to benefits from agricultural production increase productivity, or yield per unit extends far beyond the simple monetary water used. At the higher farm scale (i.e., measures and well into employment, food multiple fields), water management and security, and other rural and social bene- technology to improve productivity fits. Another simplifying assumption for attempts to minimize irrigation deliveries, water productivity assessment at higher taking into account field-to-field runoff and scales is to ignore trade-off since water reuse wherever practiced or appropriate. consumed by one user is denied to others At the farm scale, water productivity can including the downstream users. As water also be examined as the ratio of yield per becomes scarcer, the marginal cost of unit of water used for each field, but a sin- such loss becomes significant. Analysis of gle farm level water productivity value trade-off between the competing uses defined as total biomass per total water requires comparative production functions, used may not be meaningful if varying most of which are non-linear and which crops (grains vs. vegetables) are produced may have poorly defined interactions over at different fields. Farm water productivity and above those connected with water expressed in economic returns would be use. more appropriate. Since there are feed-back effects of At higher scales, the interest is in defining changing water use in the hydrologic the amount of water depleted in agricul- pathway like the upstream-downstream tural production, which includes crop interactions, it may also be necessary to evapo-transpiration, evaporation losses consider the impacts of different interven- from return or unused flows and losses to tions and the scale of adoption in a way sinks, such as saline groundwater. In meas- that internalizes hydrologic feedback in uring depleted water, the flows not used terms of water quantity and water quality. by the crop and returned to the system One way to do this is by integrating the must be accounted for as these are no production system, the hydrology, and the longer quantity losses, although quality economics within a single modeling frame- degradation may be a factor reducing work. This is much easier said than done, value. As the scale of the systems analysis particularly in developing countries where increases beyond the field, estimating the limited data is available. total value from water use increases in complexity. For instance, a basin includes

14 Methodology for Assessment/ Diagnosis of factors is also complex, but important for WP in Karkheh assessment and diagnostic purposes. Furthermore, the specific factors that Besides extensive field and on-farm WP directly and/or indirectly impact the pro- research experiments, assessing agricultural ductivity of water differ between similarity water productivity across the whole zones. For instance, some factors like pre- Karkheh River Basin in Iran (in addition to cipitation amount and distribution have a other basins of Amu Darya in Central Asia greater impact in rainfed cropping than in and Euphrates in West Asia)) is also an the irrigated system. Identifying and map- important activity with the CP WF project. ping the spatial coverage of these factors The basin-wide water productivity assess- across the watershed can help with the ment requires a sound methodology as needed diagnostic analysis of the spatial there is no current workable methodology variability of WP. The variables of interest for this purpose. In April, 2005, a consulta- are precipitation, temperature, soils, topog- tion workshop was held at ICARDA, raphy, livelihoods (including customs and Aleppo, Syria, to develop a framework for cultures), and management. As a first step, assessment of agricultural water productivi- spatial coverage maps of these variables ty (WP) at the river basin level and to dis- are being produced, in addition to maps cuss different aspects related to water pro- showing the agricultural statistics for the ductivity concept and assessment. Many agriculture services administrative bound- prominent scientists and experts drawn aries. from different CGIAR institutes, NARS and universities, and CP projects from Iran, The agriculture administrative areas or dis- Egypt, Syria, Turkey, Philippines, Brazil, tricts within watersheds offer an immediate Colombia, China, Kenya, Uzbekistan, source of yearly baseline data and long- Turkmenistan, Sri Lanka, USA, and Ghana term statistics for yield, prevailing systems, attended the workshop. Using the feed- water resources, and livelihoods as collect- backs from the above workshop, a team ed by NARS. In the case of Karkheh, of ICARDA scientists is currently formulating national statistics are available every five a framework for the assessment and diag- years since 1950, with each census data- nosis of agricultural water productivity at base including many attributes per village the river basin level. Simplicity and worka- that can be aggregated to other scales of bility are paid due consideration in devel- district, township, and province for spatial oping this framework. variability analysis of biophysical parame- ters that may help capture cultural, policy The objective of the methodology (Oweis issues, and management characteristics of et al., 2007, draft) is to set a generic frame- the administrative districts that may have a work for assessing the water productivity at bearing on yield and the productivity of basin/sub-basin level under existing or pres- water. These maps will be compared with ent conditions across a basin. The method- (or overlaid on) WP maps to deduce con- ology employs GIS, modeling, and the use straints and limitations to low WP values of satellite imagery to delineate the larger and the causes of the spatial variability in basin into similarity zones and will be pre- WP for a given land use and across differ- sented in subsequent reports. Briefly, the ent land uses. Any spatial correspondence methodology considers the productivity of or correlation between a WP map and any a unit of water used, i.e., to grow a given other climate, soil, topography (elevation crop, as a complex function of many fac- and slope), yield, livelihood and poverty tors, including climate, soils, topography, level, and cultural and management skills management, and the inputs. Capturing can then be documented as possible con- the variability of WP as caused by these

15 straints or sources of variability in WP for fur- as first level classification zoning of the ther in-depth study. Any spatial correspon- basin; 3) selecting representative water- dence between these maps will be valu- sheds with each zone that encompasses able information in diagnostic analysis of the major land uses; 4) estimating WP WP variability. The usefulness of the WP across the selected watershed(s) for all mapping in conjunction with developing land uses; and 5) out-scaling WP values coverage for other factors listed above is from watershed(s) to zones and to across that it identifies the communities or areas the basin. The methodology should lead to within the basin that is in need of a closer multiple outputs as discussed previously, examination. That we call 'direct sampling' but by far the most important are the pow- as opposed to the traditional 'random' or erful maps of WP and other variables 'grid' sampling of the whole basin. Direct known to cause variations in WP across the sampling of the communities where the basin. These other maps include the spatial above diagnostic procedure shows corre- variability in precipitation, temperature, lation between WP and other related fac- soils, topography, and livelihoods and tors is an efficient sampling strategy and management. Maps of WP across the should save time and money. basin help identify the variability over the prevailing gradient of precipitation, tem- Overlaying the WP map and the other cli- perature, soils, elevation, and slope in mate, topography, soils, and livelihood (or addition to the gradient of poverty and poverty) maps is suggested to help tag- livelihoods. Comparison of these maps ging low WP areas with the prevailing cli- should provide valuable, yet holistic, infor- matic and bio-physical and social condi- mation as to the probable causes of the tions. It is generally observed that the poor- variations in WP. er and less educated the community, the lower the productivity due to inadequate The above discussed methodology is in its management, technical support, machin- infancy and should be further perfected ery, capital, and quality seeds and fertiliz- and polished. Future work on this method- ers in addition to farmers' lack of desire for ology will concentrate on practical appli- improvement. The overlaying of WP and cations of the methodology to a range of poverty maps may even prove to be an basins, starting with KRB, to gauge its use- effective and simple methodology for fulness and improve data gathering and socio-economists to map poverty using a computations. WP map as a surrogate or proxy. Rainfed, irrigated, and a combination of CONCLUDING REMARKS AND the two are major agro-ecosystems across FUTURE WORK the Karkheh River Basin. These agro-ecosys- tems are the natural outcome of the pre- vailing aridity of the climate and the state The focus of the KRB water productivity and availability of the surface and ground- project is on research and capacity build- water resources. For instance, the rainfall is ing in rainfed and irrigated agriculture. An limited to below 250 mm in the irrigated important outcome of the project will be a lands, mostly located in the arid environ- workable methodology to assess, map, ments where rainfed production is not sus- and conduct diagnostic analysis of WP of tainable. The rainfed zone is dictated by major land uses across the basin using a lack of adequate surface and ground systematic and logical order of: 1) down- water for irrigation but significant winter scaling across the basin to delineate major and spring precipitation (> 250 mm) for sus- land use areas; 2) using the land use cov- tainable dryland farming. Within the rain- erage to delineate major agro ecosystems

16 fed cropping areas, there are usually pock- REFERENCES ets of irrigated summer cropping, making up the mixed zone. Dryland Agricultural Research Institute - Iran. 1999-2002. Annual Reports (in Persian). The future expansion of supplemental irri- Fatemi, M.R., Shokrollahi, A., and M.H. Shiroy. gation in the upper catchments can have 1994. Impacts of land consolidation on irriga- various impacts on downstream water flow tion efficiency in Dez Irrigation Network. In: Proc. of thse 7th Seminar of Iranian National in the river. These impacts could be posi- Committee on Irrigation and Drainage. IRN- tive or negative depending on many fac- CID Publication No.7 (in Persian). tors. Higher water use upstream of the river Jamab Consulting Engineers. 1991 and updates may decrease flood risks downstream, in the following years. The Comprehensive depending on the river hydrological char- National Water Plan (of Iran). Numerous acteristics and its vulnerability to flooding. reports and maps that include Karkheh River On the other hand, water withdrawal Basin. Published by the Ministry of Energy (in upstream, may decrease water supply Persian). downstream and bring about conflict of Keshavarz, A. 2005. Water Productivity at Karkheh Basin, In: Comprehensive interest between farmers. Improved man- Assessment Water Productivity Workshop. agement of rainfed areas (such as replac- April, 2005, Aleppo, Syria. ing fallow with a crop) can decrease soil Keshavarz, A. and K. Sadeghzadeh. 2000. erosion and the sediment load that is filling Agricultural water management: current situ- up the reservoir of the Karkheh Dam. These ation, future perspective and some strate- and other similar potential impacts of the gies for its optimization. In: Proc. of the 10th project should be carefully studied and the Seminar of Iranian National Committee on negative impacts minimized by adoption Irrigation and Drainage. IRNCID Publication of appropriate policies regarding the No.38 (in Persian). Mir-abolghasemi, H. 1994. Evaluation of irriga- extent and location of application of dif- tion efficiency in some traditional networks ferent technological options. The of Iran (including the southern parts of the upstream/downstream interactions are an Karkheh River). In: Proc. of the 7th Seminar of important research activity within the KRB Iranian National Committee on Irrigation and project, particularly the impact of addition- Drainage. IRNCID Publication No.7 (in al water use upstream by supplemental irri- Persian). gation of winter crops and its impact on Moemeni, A. 2003. Soils of Karkheh River Basin. A water resources at the dam This activity is Power Point presentation at the First Meeting currently led by a team of scientists from of the CP Crop Water Productivity, Feb, 2003, Karaj, Iran. AERI in Iran and ICARDA, requiring exten- Molden, D. 2007. Water for Food Water for Life: sive GIS and basin-wide flow routing and A Comprehensive Assessment of Water modeling. Management in Agriculture. Sponsored by Ramsar, CGIAR, FAO, CBD, EarthScan: In the lower basin of KRB, over irrigation or London, UK. expansion of irrigated areas could lead to Tavakoli, A. R., Oweis, T., Ferri, F., Haghighati, A., increased salinity in the southern sections Belson, V., Pala, M., Siadat, H., and Ketata, of the basin. The extent of such risks needs H. 2005. Supplemental Irrigation in Iran: to be evaluated and ameliorative meas- Increasing and stabilizing wheat yield in rain- fed highlands. On-Farm Water Husbandry ures taken before the problems worsen. Research Report Series No.5. 46 pp, ICARDA. Adjusting irrigation management in such a way that drainage water is minimized will help in lowering the risks downstream.

17 18 CHAPTER II Supplemental Irrigation in Iran

Ali Reza Tavakoli1, Abdolmajid Liaghat2, Shahram Ashrafi3 and Fariborz Abbasi3

1Irrigation and Drainage Engr., Dryland Agricultural Research Sub-Institute, Agricultural Research and Education Organization (AREO), Ministry of Jihad-e Agriculture, Kermanshah, Iran 2 University of Tehran, Irrigation Engineering Dept, Karaj, Iran 3Agricultural Engineering Research Institute (AERI), Karaj, Iran

19 INTRODUCTION water productivity in the dry rainfed areas of Iran. Rainfed agriculture covers large areas of land in Iran where wheat (Tritium aestivum SUPPLEMENTAL IRRIGATION IN L.) and barley (Hordum vulgare L.) are the WANA major crops grown. Other rainfed crops are pulses, oilseed, tea (Camellia sinensis L.), In the highlands of West Asia and North citrus (Citrus spp.), vegetables, grapes (Vitis Africa (WANA) region, frost occurs spp.) and figs (Ficus carica L.). It is most between December and March, placing likely that high dependency on irrigated- field crops in a dormant mode during that agriculture would not be able to meet the period. In most of the years, the first rainfall, food and feed demands in future. Nearly necessary for seed germination, occurs 10% of the country's total agricultural prod- after October resulting in poor crop estab- ucts are derived from rainfed agriculture. lishment especially since frost occurs in Areas under rainfed wheat and barley December and stops plant growth. were 3.95 and 1.11 million ha in 1997-98 Therefore, rainfed yields are much lower and 4.032 and 0.87 million ha in 2003-04, compared to well established crops when respectively (Tavakoli et al., 2005). crop growth takes off in early spring. According to the official documents pub- Ensuring a good crop stand in December lished by the Ministry of Jihad-e-Agriculture, can be achieved by early sowing and the total production of rainfed wheat and applying a single irrigation in October. barley were 4.69 and 0.82 million tonnes in Single irrigation applied at early sowing 2003-04 seasons (Tavakoli et al., 2005). Low dramatically increases wheat yield and variable rainfall, high evaporation because plants which emerge earlier in rates, long dry periods, relatively low soil the autumn grow more vigorously and fertility, poor seed quality and inappropri- yield much more in the following spring ate agronomic practices applied by farm- than plants which germinate late. A four- ers contribute to low yields in the rainfed year trial, conducted at the central areas. Presently, the national average yield Anatolia plateau of Turkey, showed that of wheat and barley under rainfed condi- applying 50mm of SI to early sowing wheat tion are 832 and 934 kg/ha respectively increased grain yields by more than 60%, (Tavakoli et al., 2005). Rainfed wheat yield adding more than 2 t/ha to the average is about a quarter of that from irrigated rainfed yield of 3.2 t/ha (ICARDA, 2003). fields, which is 3200 kg/ha. Water productivity (WP) reached 5.25 kg grain/m3 of consumed water, with an aver- Rainfall variability and unreliability of rainfall age of 4.4 kg /m3. The study also revealed events prevent the farming community that SI applied later in the spring and early from larger investments into the production summer further increased yield, but result- system. The prevailing high risk in rainfed ed in lower water productivity. Similar agriculture need to be addressed given results were obtained in the highlands of the increasing food demand for a bur- Iran at Maragheh (Tavakoli and Oweis, geoning population. New ways and meth- 2004). ods of production are needed to increase and stabilize crop production in these Water scarcity in WANA is a well-known areas. Optimized supplemental irrigation and alarming problem because water in techniques have shown promising results to this region is the scarcest in the world and overcome low level and unstable yield lev- water-related issues have become els. This review highlights the major extremely acute and even critical. Today, research findings regarding improving this problem is arisen the concern of

21 national governments and research institu- rect benefits associated with these systems. tions. In WANA countries, agriculture In the dry areas, water, not land, is the accounts for over 75% of the total con- most limiting resource for improved agricul- sumption of water. With rapid industrializa- tural production. Therefore, maximizing tion, urbanization and high population yield per unit of used water (water produc- growth (up to 3.6% per annum), water is tivity), and not yield per unit of land is the increasingly reallocated from agriculture to suitable criterion to compare production other sectors though the demand for more systems or technologies. Agricultural pro- food and fiber continues to increase. ductions and livelihoods in dry areas can be sustained, only if priority is given to Two distinct environments may be identi- improving water productivity and enhanc- fied along a transect within the dry areas ing the efficiency of water procurement. In of WANA. The first is the relatively wet zone, other words, more food, feed and fiber where winter rainfall is enough to support must be produced using less water. purely dry farming systems. Since rainfall amounts and its distribution in this zone are Many technologies to improve water pro- usually suboptimal, moisture stress periods ductivity and the management of scarce often occur once or twice during crop water resources are available. Among the growth causing very low crop yields. most promising and efficient-proven tech- nologies are: (i) supplemental irrigation (SI) Variation in rainfall amounts and distribu- for optimizing the use of the limited water tion from one year to the other causes sub- available from renewable resources in rain- stantial fluctuations in production that can fed areas, and (ii) water harvesting (WH) range from 0.3 to over 2.0 t/ha in the case for improved farmer income in drier envi- of wheat. This situation creates instability ronment (Oweis and Hachum, 2003, 2004). which negatively affects household Improving crop water productivity, howev- incomes. Small and scattered rainstorms in er, refers not only to a more efficient use of these regions fall on lands that are gener- water resources but also includes all other ally degraded with poor vegetative cover. inputs such as improved germplasm, fertility These areas have been affected by over- and cultural practices. grazing, and by removal of bushes for fuel wood, leading to desertification. Although The goal of supplementary irrigation is to rainfall is low when expressed in annual provide enough water during critical average, it constitutes a huge volume of growth stages to produce optimal yield ephemeral water over the entire season. per unit of water, not to provide stress-free While it forms a major water resource, it is conditions throughout the growing season lost almost completely through direct with the aim of producing maximum yield evaporation or through uncontrolled (Oweis et al., 1999). runoff. Therefore, agricultural productivity The foremost concern in arid and semiarid of rainwater in these areas is extremely low. areas is availability and efficient use of water. In drylands in North America Most of the agricultural area of WANA is (Winhold et al., 1995; Campbell et al., rainfed and a large proportion of the 1993b; Music et al., 1994), the major con- region's agricultural livelihood is based on straint to wheat is low rainfall. Though crop Dryland farming systems. While irrigated yields under dryland conditions are related areas may produce far higher yields and to seasonal rainfall, water use efficiency marketable surpluses, the overall value of can be substantially improved by crop Dryland production is much greater than its management practices (Cooper and market value due to social and other indi- Gregory, 1987; Keatinge et al., 1986; Haris

22 et al., 1991) and fertilizer use (Harmsen, 1994), but also on the cultivars as well 1984; Keating et al., 1985; Ryan and Matar, (Anderson, 1985; Guy et al., 1995). 1992). Wheat production and water use Another yield determining factor in dry- efficiency under rainfed conditions are low lands is the sowing date. Research in and subject to substantial yearly fluctua- Australia’s Mediterranean climate showed tion due to erratic rainfall and poor distri- that delayed sowing after the optimum bution (Simane, 1993). time, which coincides with the onset of seasonal rains, consistently reduced yields Northern is a typical rainfed area in (O'Leary et al., 1985; French and Schultz, the West Asia region where most of the 1984; Batten and Khan, 1987). In Cyprus, grains of the country are produced. In a agronomic research showed the impor- rainfall zone (from 300 mm to 500 mm with tance of early sowing (i.e., in November) non-uniform temporal and spatial distribu- resulted in higher wheat production per tion), huge investments in SI systems were unit area (Photiades and adjichristodoulou, put to overcome rainfall shortages. The 1984). In Iraq, during the 1997/98 season results of studies conducted by ICARDA which was very dry, for every week and Iraq showed that substantial improve- delayed in sowing, there was a resultant ment can be made in yield and WP by grain yield reduction of 220 kg/ha for rain- using SI in conjunction with proper produc- fed crops, and 520 kg/ha for crops under SI tion inputs and system management (Adary et al., 2002). One of the practical (Adary et al., 2002). In the growing season problems of SI is that all the fields may of 1997-98 (annual rainfall 236 mm), rainfed need irrigation at the same time in the wheat yield increased from 2.2 t/ha to 4.6 spring. The result is a very high water supply t/ha by applying 68 mm of irrigation water and large irrigation system is required. A at the critical time. Applying 100 to 150 multi-sowing date strategy reduced the mm of SI in April and May achieved near peak farm water demand rate by more maximum results. Early sowing (November) than 20%, thus potentially allowing a is the optimal sowing date for wheat in reduction in the irrigation system size and northern Iraq. Every week of delay in sow- cost (Oweis and Hachum, 2001). ing may result in a grain yield loss of up to 0.5t/ha of wheat. Yield, increased signifi- At ICARDA several barley genotypes were cantly with increased levels of nitrogen fer- supplemental irrigated to replenish 33, 66, tilizer rates. Hence farmers were strongly and 100% of the deficit soil moisture in an advised to monitor the soil N content for area with total rainfall of 186 mm. The economical and environmental reasons. mean grain yield was 0.26 t/ha (rainfed); As fertilizer N responses are directly related 1.89 t/ha (33% SI); 4.25 t/ha (66% SI); and to rainfall under Dryland conditions (Ryan 5.17 t/ha (100% SI). Among the genotypes, et al., 1991; Campbell et al., 1993a; Pala et Rihane-3 produced the highest yield which al., 1996), N use should be correspondingly was 0.22, 2.7, 4.75, and 6.72 t/ha respec- greater, when SI is also applied (Tavakkoli tively for the four SI treatments. These dra- and Oweis, 2004, Tavakoli et al., 2005; matic results under SI were obtained partly Feiziasl, 1997; Belson, 1999; Oweis, 1997; because of the drought during this season Oweis et al., 1999; Ramig and Rhoades, (ICARDA, 1989). 1963). However, the response of wheat to irrigation water is dependent on the culti- SI and single irrigation are the major meth- var (Fischer and Maurer, 1978; Sojka et al., ods used in low rainfall areas to ensure that 1981; Nachit et al., 1992). Thus, the poten- crops receive enough water to produce tial yield in any environment depends not an economic yield. While water harvesting only on water and N (Aggarwal and Kalra, is generally used in areas that receive

23 between 100-300 mm of rainfall annually, SI Potential benefits that can be achieved is used in areas with a slightly greater annu- through the use of SI include increased al rainfall of approximately 300-600mm yields, stabilization of yields across years, (Oweis et al., 1999). Supplemental irrigation and creating conducive conditions for the and single irrigation have been described use of high yielding varieties, herbicides as techniques used on crops that can be and fertilizers (Oweis et al., 1999). Research grown using rainfall alone, which applies a at the ICARDA research station in northern limited quantity of water during times of Syria has shown that water use efficiency low rainfall to ensure that enough water is can be greater under SI than under rainfed received to support crop growth and stabi- agriculture. Under controlled conditions on- lize yields (Oweis et al., 1999; Perrier and station, it was found that the application of Salinki 1987; Tavakoli and Oweis, 2004; one cubic meter of water at a time of Caliandro and Boari, 1992). water stress, combined with good man- agement, increased water use efficiency In contrast to conventional irrigation, the more than twice over that of rainfed pro- quantity of water applied by SI alone is not duction (Oweis et al., 1999). sufficient to ensure full crop growth under non-stressed conditions. Conversely, con- In the dry areas, water, not land, is the ventional irrigation supplies the entire water most limiting resource for improved agricul- needs to the crop because rainwater may tural production. Increasing water produc- not provide sufficient water for plant tivity, instead of yield per unit of land, is growth for all or part of the season (Perrier therefore a better strategy for dry farming and Salinki 1987). Conventional irrigation is systems. Under such conditions, more effi- used in regions where water is plentiful, cient water management techniques must while SI and single irrigation is often used in be adopted. Supplemental irrigation and places where water is often scarce. single irrigation are highly efficient prac- tices with great potential for increasing Timing of water application is one of the agricultural production and improving most important factors to be determined livelihoods in the dry rainfed areas when using SI. Supplemental water appli- (Tavakoli and Oweis, 2004, 2006). Average cations are especially important when rainwater productivity of wheat grains in water is scarce during critical growth peri- WANA is about 0.35 kg/m3 (Oweis and ods. Hachum, 2003 and 2004). However, it may The water used for SI can be obtained increase to as high as 1.0 kg/m3 with from different sources. Groundwater, sur- improved management and favorable face water, industrial wastewater, and rainfall distribution. water obtained through water harvesting methods are all used for SI. The water har- In the drier environments, most of the rain- vesting methods are often used in conjunc- water is lost by evaporation; therefore the tion with SI since SI is often undertaken in rainwater productivity is extremely low. low-rainfall areas. Important factors to be Water harvesting can improve agriculture considered while designing a water har- by directing and concentrating rainwater vesting system for SI include the storage to the plants. It was found that over 50% of capacity, the type of storage and storage lost water can be recovered at very little location. Specific methods of irrigation costs. used depend upon the resources available to the farmers in an area as well as any Among agronomic practices, application economic or labor costs that may be of nitrogen, SI and early sowing of appro- involved with setting up the SI system. priate cultivars are widely recognized as a

24 means of increasing wheat yield in the dry the east and Iraq in the west, and a few areas (Cooper et al., 1987; Siddique et al., rivers along the northern, western and east- 1990; Anderson and Smith, 1990; Oweis et ern borders. Iran is located between 25° to al., 1998). The introduction of SI to winter 45° Northern Latitude and between 44° to cereals can potentially stabilize and 64° Eastern Longitude. The country is situat- increase yields, as well as increase the use ed in the arid to semi-arid belt of the world. efficiency of water received both from It has an area of about 1.65 millions square rainfall and from irrigation (Oweis et al., kilometers within the West Asia region and 1992; Tavakoli and Oweis, 2004; Tavakoli et has a population of about 69 millions al., 2005). In the rainfed regions of Iran, (UNDP, 2004). The country's food produc- application of single irrigation at planting tion largely depends on irrigated agricul- time and heading-flowering growth stage ture particularly in the central plateau for winter cereals (wheat and barley) can where the annual rainfall is usually below increase yield from 500 to 2500 kg/ha and 150 mm. Due to sufficient rainfall the north- from 500 to 1000 kg/ha, respectively ern and western parts of the country pro- (Tavakoli, 2001; Tavakoli et al., 2000). duce rainfed cereals, orchard and other Nitrogen deficiency, after drought, is the annual crops. major constraint in dryland cereal farming (Campbell et al., 1993a; Tavakoli and Generally, the dry climate of Iran is affect- Oweis, 2004). Within the Mediterranean ed by various geological features. Most of areas, N deficiency is ubiquitous, being the rivers in low precipitation areas (100- extensively reported from Morocco 200 mm annual rainfall) receive water from (Mossedaq and Smith, 1994; Ryan et al., snowfall on high mountains during winter. 1992; Shroyer et al., 1990) to Syria According to the National Water Plan (Anderson, 1985; Harmsen, 1984) and (NWP), Iran is divided into eight climatic prevalent in many countries of the region zones as follows: (Ryan and Matar, 1992). • Very Arid: This zone covers an area of Water resource management strategies 57.4 million ha (35.4% of the total area). have become more integrated and cur- It has very hot and dry climate with rent policies look at the whole set of tech- mean annual precipitation of 150 mm nical, institutional, managerial, legal, social, and annual potential evapotranspira- and operational aspects required for tion (ETO) between 2700 and 3000 mm development at all scales. Sustainability is prevail. a major objective of national policies. A • Arid: This zone covers an area of about sound strategy of an integrated approach 47 million ha (29% of the total area). It for natural resources management in the has a hot and dry summer climate, and drylands deals with water as the central warm (south) or cool (north) winter cli- issue and using it efficiently is accorded mate. Mean annual precipitation and highest priority. annual ETO is estimated to be between 150-250 mm and between 2400-2700 SUPPLEMENTAL IRRIGATION IN IRAN mm, respectively. • Semi-arid: This zone covers an area of Climate in Iran about 33 million ha (20% of the total area). It is hot in summer and cool in Iran is bounded by the Caspian Sea, the winter. Mean annual precipitation Republic of Azarbaijan, the Republic of ranges between 250 and 350 mm and Armenia, and Turkmenistan in the north, annual ETO varies between 2000 and the Persian Gulf in the south, in 2400 mm.

25 • Mediterranean: About 8 million ha (5% Rivers are the main sources of fresh water of the total area) falls in this zone. The in Iran, in addition to hundreds of perennial climate of the zone is characterized as and ephemeral streams. The main rivers warm in summer and cool in winter with include the (890 km), Sefidrood (765 mean annual precipitation of 350-450 km) in the north, Karkheh (755 km) in south- mm and annual ETo between 1700 and west, Mond (685 km) in southeast, Qara- 2000 mm Chay (540 km) in north central, Atrak (535 • Semi-humid: While warm in summer and km) in northeast, Dez (515 km) and cold in winter, this zone covers an area (488 km) in southwest, Jarahi (438 of about 5.5 million ha (3% of the total km) in southwest, and Zayandehrood (405 area). Mean annual precipitation and km) in the central. annual ETO for this zone varies from 450 to 550 mm and1400 to 1700 mm, The renewable water resources of the respectively. country, both surface and groundwater, • Humid: This zone is warm in summer and were estimated to be about 130 km³/year. cool to cold in winter. Mean annual pre- The annual surface and groundwater flows cipitation ranges from 550 to 700 mm were estimated to be at about 97 and 33 and annual ETO ranges between 1200 km³/years, respectively. Drainage of and 1400 mm. It covers an area of contributes to about 5.4 km³/year about 6 million ha (4%) to the total annual surface runoff. These • Very humid (type A): The climate of this water resources depend on countrywide zone is warm in summer and cool to average annual rainfall of 25 2 mm; about cold in winter. Mean annual precipita- the two-third of the country receives less tion ranges from 700 to1000 mm and than this amount in a normal year. More annual ETO varies between1000 and than 60 dams store a large part of the sur- 1200 mm. It covers an area of about 5 face runoff. Recently constructed, Karkheh million ha (3%) Dam with a reservoir capacity of about 7 • Very humid (type B): Warm climate in km3 is the largest among all these dams. summer and very cold in winter at high Based on a policy of better utilization of altitudes. This zone receives mean annu- surface water resources, another 70 or al precipitation of 1000-2000 mm and more dams are needed with a total annual ETO occurs between 800 and capacity to store 19.6 km³ of surface water 1000 mm. It covers an area of about 1 resources. (Ghodratnama, 1998; Jamab million ha (0.5% of the total area). Consulting Engineers, 1991).

According to this classification, the main Long-term average data show a ground- rainfed areas of Iran are located in the water recharge of about 50 km³/year. An Semi-arid and the Mediterranean zones, annual overdraft of about 5 km3 has been with some relatively smaller areas in the reported for the entire country during last Semi-humid parts. decade. Groundwater overuse in 150 plains of the country amounts to a total Water Resources volume of about 4 km³. This figure rose to 6.9 km³ during 1998-2000 and about 11 km³ The annual per capita share of renewable during 2000-01, mostly due to drought. water resources in Iran is estimated to be 2015 m3. Due to the geographical distribu- However, not all of the renewable water tion of the water, many parts of the coun- resources are used. Presently, the total try experience different levels of water annual water uses are estimated to be scarcity. about 88.5 km3. Water use by different sec-

26 tors varies from year to year, particularly PREVIOUS SUPPLEMENTAL due to annual variations in the available IRRIGATION RESEARCH water. The agricultural sector demands more than 90%, while domestic (rural and A literature review of past research efforts urban areas) and industrial sectors utilize indicates that the relation between rainfall about 5.5% and 1%, respectively. Nearly amount and crop yield in dry-farmed zones 0.5% is used for fish ponds and for the con- of Iran has been a subject of interest since trol of the downstream water depth. It is last decades. Mirnezami (1972) concluded important to note that the percentages that the rainfall is the most important factor indicated for the different sectors, particu- limiting the yield of rainfed wheat in Iran. larly for agriculture, includes the water He stated that a threshold value of 295 mm "used" for power generation and flood of rain is necessary to achieve a satisfying control. Domestic and industrial sector yield level. In the same study, the correla- shares are expected to rise in the future tion coefficient of the linear relationship due to population growth and economic between wheat yield and six different development. moisture indices were in the range of 0.928- 0.981. Hashemi (1973) found a positive cor- WATER PRODUCTIVITY (WP) relation coefficient of 0.78 between dry- CONCEPT land wheat yield and the total annual rain- fall in different parts of Iran, excluding the The productivity of applied water is Caspian Coast and area with annual rain- defined as crop yield per unit volume of falls greater than 600 mm. His analysis water use. Volume of water use refers to showed a lower and more variable yield irrigation, rainfall or the summation of the response as rainfall approaches 400 mm. two amounts. Rain water productivity Bookers et al. (1975) prepared a country (RWP) is the ratio of rainfed yield to total map showing the suitable areas for supple- rainwater, irrigation water productivity mentary irrigation. However, they did not (IWP) is the ratio of total yield to irrigation give the criteria used for such planning. water use, gross irrigation water productivi- ICARDA's initiative to identify the potential ty (GIWP) is the ratio of increased yield to for SI in Iran and in the Near East including the gross depth of applied water and total a workshop held in Rabat, Morocco, was a water productivity (TWP) is the ratio of irri- major milestone in presenting a concrete gated yield to total water supply (rain + irri- scientific output on this topic in the region gation), or simply: (Perrier and Salkini, 1987).

Yield Siadat (1987) carried out a countrywide RWP = (1) survey and prepared a report on the rain potential of SI in Iran. The report cites sever- Yield al locations where farmers practice SI dur- TWP = (2) ing years of below-normal precipitation. + irr. rain Only one irrigation to wheat and barley in Yield almost all of such cases increased the IWP = (3) grain yield by 50 to 100%. There are indica- irr.water use tions that this single irrigation increased the Yield −Yield yield to a level higher than the average GIWP = irr rainf ed (4) yield obtained in normal years. This may be irr due to the effect of timely irrigation in con- trast to the precipitation in a normal year that may not fall in the right time. Another

27 important finding of this survey was the the first month after planting. According to fact that almost everywhere water for SI the improved relationship, 84% of the varia- was taken from wells. This is noteworthy tions in the yield can be described by the since SI is practiced in dry years, when the changes in ETa values. This is a rather surface streams are limited or non-existent strong relation that supports the applica- and the only reliable source of water tion of SI in order to maintain crop transpi- would be the groundwater. ration when rainfall is inadequate.

In the 1990's, interest in the research on SI Hashemi (1973) found a correlation coeffi- started to grow and a series of experiments cient of 0.78 for the positive linear of rela- were designed and conducted in various tionship between wheat yield and amount regions of Iran by the staff of the Soil and of precipitation in various parts of Iran Water Research Institute (SWRI) and, later, except when rainfall exceeds 600 mm. In a by the newly established Dry-land study by Mirnezami (1972), the author con- Agricultural Research Institute (DARI) cluded that precipitation was the most (Moradmand, 1991; Naseri, 1993; Kalantari, important limiting factor affecting yield of 1993; Moradmand et al., 1994; Niazi and rainfed wheat. The linear relationship Javaheri, 1996; Sayadyan, 1997). Results of between wheat yield in these areas and six some earlier experiments in this series were moisture levels considered in Mirnezami's mixed. In some years SI had little or no study gave a correlation coefficient of impact, and in other years the effects were 0.928-0.981. significant. Also, some findings indicated that the location of a particular experi- An experiment carried out during 1983-87 ment was not suitable for rainfed produc- at Tikmeh-Dash Research Station located in tion since the yields were very low without the northwest of Iran showed that SI of rain- irrigation. fed wheat at heading and grain formation stages results in an average yield of 1748 The relationship between the amount of kg per ha of wheat. In the same experi- precipitation (evapotranspiration and/or ment, one irrigation (single irrigation) soil moisture status) and the yield of dry- applied at either of these stages resulted in land wheat was studied. A final point to be a yield of 1500 kg/ha. Comparing these discussed is the relation between ETa and data with the average yield of dryland crop yield. For the data obtained in crops, which is below 1000 kg/ha, shows Maragheh the relationship (R2=0.74) was the potential for increasing yields with SI (Tavakoli et al., 2005): and single irrigation in same regions (Siadat, 1987). Y = 0.0093ETa – 1.384...... (5) Also, an experiment carried out during The data points are those of the three 1982-85 at Mahidash Research Station study seasons averaged over five nitrogen (near Mereck site, Karkhe River Basin rates. The coefficient of determination i.e. Project) located in the west, showed that 2 R2, is reasonably high and it indicates that applied at the heading and milk about three quarters of the variations in growth stages resulted in a 3 year average yield are associated with changes in ETa. of about 2800 kg/ha, where average yield The relationship improves by omitting the of rainfed crops in the area were 1200 result obtained for the rainfed treatment in kg/ha. 2001-02 season. This omission is justified because of the very long delay in rainfall Results of such studies can be interpreted after planting and its inadequacy during as showing the potential of increasing

28 yields and the benefits that could be SI. Recent investigations of the effect of SI expected if single irrigation or SI are on rainfed cotton and soybean on the applied. Table 1 shows the results of SI in Caspian Coast also revealed significant four districts including Miandorood, Agh- yield responses. For soybeans, three SI Ghola, Bala-Darband and Mahidasht applications, totally 95 mm of water use, (Siadat, 1987). resulted in an 80% increase in bean pro- duction when compared to yields Table 1: Yield of wheat and barley under rainfed received under rainfed conditions. In the and supplemental irrigation (Siadat, 1987). case of cotton, a 145% increase in yield District Grain yield (kg/ha) was obtained upon application of 212 mm Wheat Barley of water applied in 5 supplemental irriga- tions (Siadat, 1987). Rainfed SI Rainfed SI Miandorood 2500 3500 2750 3500 Agh-Ghola 1500 2500 1100 2000 In Kermanshah province, the best treat- Bala-Darband 1800 4000 2000 4000 ment for rainfed wheat (Sardari cultivar) Mahidasht 1200 1700 1800 2500 was found to be one single irrigation at heading to flowering stage (Sayadyan and Miandorood district is located in the Tallie, 2000). The increase of barley grain Mazandaran Province in the coastal area and straw yield by single irrigation was of the Caspian Sea. Agh-Ghola district is highly significance. situated in the Golestan Province along the coast of the Caspian Sea and the east of Results of an experiment at Ghachsaran Mazandaran. Bala-Darband district is Research Station in Kohkiloyeh & northwest of Kermanshah situated in the Boyerahmad province (southern Iran) west. Mahidasht district is located 10 km to showed that single irrigation applied to the southwest of Kermanshah rainfed sunflower cultivars and just before flowering stage increased grain yields from Since mid 1990's, DARI has expanded its 1.88 t/ha under rainfed conditions to 2.94 research activities on this topic. t/ha by single irrigation before flowering Experiments on SI and single irrigation stage (Absalan, 2005). became part of research activities of a number of research stations run by DARI in Poordad (1996) reported from Kermanshah different parts of the rainfed zones of Iran. region significant grain yield increases due These experiments were designed based to the application of one single irrigation on climate data of DARI's stations at differ- for different sunflower cultivars. ent parts of Iran (Mahmoodi, 1997-2005). Later, with the help of ICARDA's expertise, Flowering growth stage and early filling additional periments were conducted in pod was the most critical time for rape- some of the stations supervised by DARI. seed (canola) and single irrigation at these periods increased yield (Richards and Corresponding research activities investi- Thurling, 1978; Rao and Mendham, 1991; gating other crops under rainfed condi- Pasban-Eslam et al., 2000, Tavakoli, 2004b; tions have also shown significant results. Dehshiri et al., 2001) and the number of Experimental data on tea production from pod per square meter and the number of 4-years water and fertilizer trials conducted seed per pod (Clarke and Simpson, 1978; by SWRI showed appreciable yield increas- Mendham et al., 1984, Tavakoli, 2004b). es with SI. In 1970 and 1971, yields increased on average by 2179 kg/ha and Food legumes are important crops in 1593 kg/ha, respectively, as a result of four WANA, particularly for providing low- cost

29 protein for people with low incomes. by 2460 kg/ha compared to rainfed condi- Rainfed yields are low for the same reasons tion. The same results were reported by outlined earlier for cereals. For chickpea, Sayadyan and Sadjadi (1997). the final growth stages (pod initiation and Niazi and Javaheri (1996) carried out an seed development stage) is the most criti- experiment at two cold and warm climates cal time and single irrigation at these peri- of Fars Province and showed that the best ods increase grain yields as well (Tallie and treatment for rainfed wheat at cold region Sayadyan, 2000; Kochaki and Banayan- was one time irrigation (single irrigation) at Avval, 1993; MajnonHoseini, 1993). For heading stage and at warm region is SI at Kermanshah condition, it has been report- during stem elongation, heading and flow- ed that single irrigation at seed develop- ering stages. Fars province is located in the ment stage had the highest effect on south of Iran. increasing grain yield (Tallie and Sayadyan, 2000) and irrigation water productivity was An experiment carried out by Taoshih 5.9 kg/mm. (2002) during 1995-98 at Ghamloo station located in the Kordestan province (west of In a long term experiment from 1989 to Iran), reported that the single irrigation 1996, carried out at Sharekord station strategy in mid October improved the yield located in the Charmahal & Bakhtiyari of rainfed wheat cultivar (). In spite province (central of Iran), average grain of variation in climatic conditions for every yield of rainfed wheat with single irrigation season, considerable increases of grain at flowering stage, with double irrigations yield and thousand kernel weight of single at flowering stage and filling stage and irrigation at planting time showed prefer- grown under rainfed condition was 1896, ence relative to other treatments (rainfed 2400 and 314 kg/ha, respectively and single irrigation at spring time). Single (Moradmand, 1998). irrigation at planting time increased grain An experiment carried out by Haghighati- yield by 154% compared to rainfed condi- Maleki (1998) at Maragheh Research tion. Station located in the northwest of Iran showed that 50 mm single irrigation of rain- In wet years, with sufficient rainfall (amount fed barley at planting time increased to and distribution), SI at spring time (heading, 500 kg/ha grain yield as compared with flowering or filling stages) for wheat and rainfed condition. This increase of barley barley did not have significant effects on grain yield by SI was highly significance. increasing yield (Kalantary, 1993; Feiziasl, 1997; Feiziasl and Valizadeh, 2001). But An on-farm experiment carried out by Tallie Feiziasl (2003) reported substantial increase (2005) at farmer's field of Kermanshah in wheat yield by one time irrigation at province, showed that single irrigation of early sowing time. rainfed improved barley variety (Sararood1) at early May (during heading Radaei and Hajiloei (1994) based on an to flowering stage) increased grain yield by experiment carried out at Hamedan 1204 kg/ha compared with rainfed condi- Province showed that the increase grain tion. Irrigation water productivity was yield of two wheat varieties (Sabalan and between 12 and 50 kg/mm. Sxl-Glenson) by one time irrigation at plant- ing time (autumn) was significant. An experiment carried out by Najib Hamedan province is located in central Mamendo (1993) at Sararood research sta- Iran. tion located in the Kermanshah province reported that a single irrigation at filling An experiment carried out by Fardad and stage of rainfed wheat increase grain yield Golkar (2002) at Tehran University located

30 in central Iran reported that the SI strategy mm, late sowing), and rainfed condition for allowed one to apply 35% less irrigation Azar2 wheat variety were 3017, 3232, 2050 water and to increase 300% cropping and 1404 kg/ha, respectively (Table 2). areas. Amount and distribution of precipitation A similar experiment was designed at the can alter the effect of single irrigation and same location to determine the response SI on the crop yield. Some reports showed of rainfed barley varieties to the single irri- that SI did not have significant effects on gation and sowing date for Maragheh increasing grain yield, especially when condition. The study was carried out during rainfall came immediately after irrigation 2004-05 season at Maragheh research sta- (Azari et al., 1994; Sayadyan, and Sadjadi, tions (DARI annual Reports of 2004-05). The 1997; Kalantari, 1993; Moradmand, 1996; rainwater productivity (RWP) ranged Najib Mamendo, 1993; Perrier and Salkini, between 2.77 and 3.04 kg/mm. Irrigation 1987). water productivity ranged between 16.56- 31 kg/mm and total water productivity was An experiment was carried out during two between 5.2-8.1 kg/mm. The average grain cropping seasons from 2002 to 2004 at yield of rainfed barley under different treat- DARI Maragheh research station to deter- ments (single irrigation 100 mm at planting mine the response of rainfed wheat vari- time, early sowing), (100 mm, normal), (50 eties to single irrigation and sowing date mm, late), (100% spring = 75 mm, normal), for Maragheh condition (DARI annual (50% spring =38 mm, normal) and rainfed Reports of 2002-2003; Tavakoli, 2005). The condition for Yesevi-93 barley advanced experiment consisted of three sowing line were 3268, 3614, 2139, 2348, 2197 and dates (early, normal and late), three SI 1019 kg/ha, respectively (Table 3). treatments (I0 = rainfed, I1 = one irrigation of

50 mm and I2 = one irrigation of 100 mm) An experiment consisted of three SI treat- and five advanced lines and cultivars of ments (I0 = rainfed, I1 = one irrigation of 50 wheat. Irrigation water was measured and mm at planting time and I2 = one irrigation delivered by a polyethylene pipe to each of 50 mm during heading - flowering stage) plot, where it was applied through a perfo- and five advanced lines and cultivars of rated pipe held at the top of the canopy wheat (V). The study was carried out dur- and moved along the basin. This method ing 1997-99 season at three research sta- was adopted to increase uniformity of tions, namely, Maragheh, Sararood, and application. The timing of irrigation was Haydarloo (Tavakoli et al., 2000; Tavakoli, based on the soil moisture content of 3 2001).The statistical design was randomized treatment. That is, whenever the available blocks with strip plots. soil moisture content in the effective root zone in I3 dropped to 50%, all plots were irrigated. In Maragheh, soil moisture was measured several times during the season, using TRIME (TDR group). The rainwater pro- ductivity was between 3.08 to 4.32 kg/mm. Irrigation water productivity were between 7.18 and 23.94 kg/mm and total water pro- ductivity was between 3.63 and 8.52 kg/mm. The average wheat grain yield of two seasons under single irrigation (100 mm, early sowing), single irrigation (100 mm, normal sowing), single irrigation (50

31 Table 2. Rainwater Productivity (RWP), total water productivity (TWP), irrigation water produc- tivity and GIWP of two new rainfed varieties of bread wheat grains in northwest of Iran. Year Rain Rainfed grain RWPa SI Rain+SI Irrigated TWPb GIWPc mm yield (kg/ha) (kg/mm) (mm) (mm) yield (kg/ha) (kg/mm) (kg/mm) V3 wheat variety (Turkey 13//F9.10/Maya"S") 2003/04 416 1368 3.29 I1 (100mm) 516 3157 6012 17.89 I2 (100mm) 516 3580 6.94 22.12 I3 (50mm) 466 1727 3.71 7.18 2004/05 368 1591 4.32 I1 (100mm) 468 3381 7.24 17.9 I2 (100mm) 468 3985 8.52 23.94 I3 (50mm) 418 2308 5.52 14.34 Azar2 wheat variety 2003/04 416 1280 3.08 I1 (100mm) 516 2995 5.8 17.15 I2 (100mm) 516 3031 5.87 17.51 I3 (50mm) 466 1692 3.63 8.24 2004/05 368 1528 4.15 I1 (100mm) 468 3040 6.5 15.12 I2 (100mm) 468 3433 7.34 19.05 I3 (50mm) 418 2407 5.76 17.58

I1: Early sowing date + 100mm single irrigation at planting time I2: Normal sowing date + 100mm single irrigation at planting time I3: Late sowing date + 50mm single irrigation at planting timea RWP is the ratio of rainfed yield to rainwater b TWP is the ratio of irrigated yield to total water supply (rain + SI) c GIWP is taken as the ratio of increased yield to the gross depth of SI water

Table 3. Rainwater Productivity (RWP), total water productivity (TWP), irrigation water produc- tivity and GIWP of two new rainfed varieties of barley grains in northwest of Iran Barley Rain Rainfed RWPa SI Rain+SI Irrigated yield TWPb GIWPcb variety mm grain yield (kg/mm) (mm) (mm) (kg/ha) (kg/ha) (kg/mm) (kg/mm) Yesevi-93 368 1019 2.77 I1 (100mm) 468 3268 6.98 22.49 I2 (100mm) 468 3614 7.72 25.95 I3 (50mm) 418 2139 5.12 22.4 I4 (75mm) 443 2348 5.30 17.72 I5 (38mm) 406 2197 5.41 31.0 Dayton 1117 3.04 I1 (100mm) 468 3249 6.94 21.32 I2 (100mm) 468 3803 8.13 26.90 I3 (50mm) 418 2158 5.16 20.82 I4 (75mm) 443 2359 5.33 16.56 I5 (38mm) 406 2226 5.48 29.18 I1: Early sowing date + 100mm single irrigation at planting time I2: Normal sowing date + 100mm single irrigation at planting time I3: Late sowing date + 50mm single irrigation at planting time I4: Normal sowing date + 75 mm single irrigation at during heading - flowering stage I5: Normal sowing date + 38 mm single irrigation at during heading - flowering stage a RWP is the ratio of rainfed yield to rainwater b TWP is the ratio of irrigated yield to total water supply (rain + SI) c GIWP is the ratio of increased yield to the gross depth of SI water.

32 Irrigation water was applied through a levels of SI and nitrogen application sprinkler system with adjustable angle. One (Tavakoli et al., 2003). Levelled and suit- sprinkler was installed at each corner of able land for basin construction to culti- the irrigated plots. The 50 mm irrigation was vate locally popular cultivars of wheat at applied after planting (I1) and 50 mm irriga- each station was used. The SI treatments tion at flowering stage (I2). Results of the included control (I0, no irrigation), I1 (1/3 of experiment are summarized in table 4. A full irrigation), I2 (2/3 of full irrigation) and I3 general reduction in the yield of all treat- (full irrigation). Five nitrogen application ments is evident during the second season. levels were exercised for each trial, which

This is mainly a consequence of the included N0 (no nitrogen application), N30 drought situation in that year, which inflict- (Nitrogen application of 30 kg/ha), N60 ed a lot of damages to crop production in (Nitrogen application of 60 kg/ha) N90 many parts of the country, particularly in (Nitrogen application of 90 kg/ha), and the rainfed areas. According to the table, N120 (Nitrogen application of 120 kg/ha). at least one of the two supplemental irriga- The source of nitrogen was urea which was tions led to appreciable yield increase in added to all treatments two times: half at all cases. Average yield increases due to SI planting time and the rest in spring. The during these two seasons in different loca- experimental design was RCBD with split- tions were as follows: in Maragheh, 53-63%, plots and three replications. The number of in Sararood, 8-66%, and in Heydarloo, 13- irrigations varied between two to four in 46%. different seasons. In the first irrigation in fall, Timing of a single SI is also important and it an equal amount of water (between 30 to seems to be site specific. Supplemental irri- 40 mm in different cases) was applied to gation, single irrigation and their timing are all irrigated plots. For the rest of the grow- effective on water use efficiency (WUE) ing seasons, the amounts of water applied and water productivity (WP). In Maragheh, in each irrigation to the I1 and I2 treatments WUE in both years was significantly higher were 33% and 66%, respectively of that for irrigation at planting than at flowering applied to the fully irrigated treatment of I3. or the rainfed treatment. At the other two Observations such as grain, straw and bio- stations, however, the best results were logical yields, harvest index, productivity obtained with irrigation at flowering time. degree, plant height, kernel number per spike, spike number per square meter and An experiment was designed at thousand kernel weights were measured. Maragheh, Sararood, and Haydarloo Yields of rainfed conditions varied with sea- research stations in 1999-2000 to determine sonal rainfall and its distribution, with all the response of wheat cultivars to various main factors having significant effects.

Table 4: Average grain yield of some advanced wheat lines under different single irrigation treatments (kg.ha-1), during 1997-99. Station Season Average of all varieties Average of all irrigation treatments I0 I1 I2 V1 V2 V3 V4 V5 Maragheh 1997-98 1491 2428 1670 1859 1811 2053 - 1729 1998-99 992 1515 1217 1258 1188 1427 - 1092 Sararood 1997-98 2511 2589 2716 2697 2577 2517 2714 2523 1998-99 882 1071 1463 1011 1216 1497 1101 869 Haydarloo 1997-98 2133 2613 3112 2150 2578 2795 2741 2832 1998-99 1205 1348 1357 1201 1432 1241 1490 1151

I0 = No irrigation; I1 = One irrigation of 50 mm at planting; I2 = One irrigation of 50 mm at flowering

33 Results of path analysis for rainfed wheat higher rates of nitrogen, particularly N120, showed that increase in grain yield was decreased yield or produced similar result due to increased seed numbers per spike, as the lower rates. In Maragheh, applica- height and straw yield, respectively. tion of all nitrogen rates in the non-irrigated

Optimum level of SI for Sabalan was 1/3 of (I0) treatment decreased yield to the levels full SI with 60 kg.N.ha-1 resulted to maximum below the control. On the other hand, at water productivity (30.1 kg.mm-1). In spite higher water application rates, wheat of 20% reduction of yield in this treatment, yields increased in response to nitrogen a maximum net benefit was obtained use. Similar trend in the response of wheat along with probability of 180% cropping to N-fertilizer and SI are reported for Syria area increase, which led to 74% increase in (Oweis, 1997). In Sararood, however, lower total grain yield. Limit of benefit ability for rates of nitrogen application may be optimum level of SI was determined as favored since N30 treatment in combination 2857 Rial/m3 water. Results of path analysis with I or I resulted in the maximum yield in for irrigated wheat showed that increase in 3 2 two of the three experimental seasons. This grain yield was resulted from increase of is probably due to higher organic carbon spike/m2, seed number per spike and straw content of the soils in Sararood compared yield, respectively (Tavakoli, 2003, 2004a). with Maragheh. Generally, these results are site-specific, but they clearly emphasize Positive impacts of SI on the yield of rainfed the need for adjusting nitrogen application wheat are generally evident in the data, rates to the seasonal availability of water in although the results of first year experiment the root zone. at Sararood were not statistically different. The highest yield increases due to SI in dif- The interactions of N x SI were highly signifi- ferent seasons/stations were mostly in the cant at Maragheh in the three years of range of 1 to 3 tons per hectare. In all study. Here, the full irrigation (I3) in combi- cases, full irrigation treatment (I3) resulted nation with N90 gave the maximum yield of maximum yield. In the first year at 3233, 4537, and 5204 kg/ha, respectively Maragheh, I2 followed that treatment in for the first to the third study season. Similar the same statistical group with I , but, it 1 results were obtained for I3 at Sararood, was in a higher group than I1 in the second though not statistically significant result was year. Probably, the lower rainfall of the found in the first two seasons. second season in that station led to a more clear distinction between the treat- However, in the first season I3 yielded a ments. Such results indicated that yield maximum of 3861 kg/ha in combination response to SI was dynamic and depend- with N30, which was nearly 1 tonne higher ent on a number of environmental factors than the corresponding rainfed treatment including rainfall. i.e. I0N30. Results for the third year at

Sararood were highly significant, with I2N30 The main effects of nitrogen were signifi- giving the maximum grain yield of 4446 cant in all cases, except in the 2001-02 kg/ha. At both stations, the minimum yield season in Sararood. The data obtained in was always obtained for the non-irrigated Maragheh suggested that the application (I ) treatment mostly in combination with of 60 to 90 kg.N/ha was the best recom- 0 N , and once with each of N and N mendation when higher amounts of water 120 0 60 were applied. Application of N resulted in treatments. Thus, it becomes apparent that 60 when precipitation falls short of the aver- the maximum yield or its yield was in the age and a relatively dry season prevails in same statistical group with the treatment these areas, use of N-fertilizer is not advis- yielding the highest. It is noteworthy that able.

34 In order to investigate the effects of single maximum amount of water productivity irrigation amounts at different stages of (4.28 kg/mm). In addition to yield increas- rapeseed on yield increase and its stabi- es, SI also stabilized wheat production. The lization, a field experiment was conducted coefficient of variation was reduced from at Maragheh agricultural research station 100% to 20% in rainfed fields that adopted of DARI, during 2002-03 on rainfed spring SI. rapeseed variety (PF.7015.91). This experi- ment was conducted as split plot arranged Strategically, SI can be exercised in one of in a randomized complete block design the following methods: (RCBD) with three replications. The treat- • Applying one or more irrigations at the ments included four levels of single irriga- specific stages of crop growth during tion amounts (Rainfed, 30, 60 and 90 mm soil-moisture stressed period. of water use) at growth stages (stem elon- • Application of deficit irrigation at the gation, flowering and filling stage). The time when soil-moisture stress occurs. observations included parameters such as WUE, WP, grain, straw and biological yield, Considering the limited availability of water harvest index, plant height, and thousand resources in the dry areas, application of a kernel weight. The analysis of variance indi- small amount of water as deficit irrigation cated that, there were significant effects could provide a chance for crop to survive due to the single irrigation amounts, growth and maintain modest growth until it stages and their interactions. There were receives rainfall or irrigation. positive significant correlations due to grain yield with all variables. The potential areas of single irrigation in Spring rapeseed grain yields increased Iran include western parts (Central Zagros under single irrigation amounts in northwest Valleys), northwestern provinces (West and of Iran, with application of limited amounts East Azarbaijan Provinces), and the of SI (90, 60, and 30 mm) at different Caspian Coast in the north. Besides these growth stages (stem elongation, flowering areas that constitute the main zones of and filling stage), when compared with rainfed agriculture, some other relatively rainfed condition. Rainfall is the major smaller areas and sub-zones, such as rain- water source for rainfed crop growth and fed areas in Fars and Khorasan provinces production, thus the amount of water that have similar agro-climatic conditions, added by SI can by itself support economi- are also suitable for SI. cal crop production. Results showed that optimum level of single irrigation for rape- In addition to wheat and barley as main seed was 60 mm water use at flowering rainfed crops, pulses, oilseed, tea, citrus, stage which produced 1071 kg grain per vegetables, grapes and figs are also grown hectare. under rainfed conditions in various parts of the country. Single irrigation and SI in Iran The WPI+P (I stand for irrigation and p for can be beneficial for raising diversified precipitation) and WPI for this treatment crops of high market values. were 4.79 and 8.09 kg/mm respectively. The water use efficiency increased from 2.0 It can be concluded that the supplemen- (rainfed) to 2.46 kg/mm-ETa (60mm single tal and single irrigation increased yields, irrigation). Scenario analysis of total pro- water productivity indices, water use effi- ductivity of applied water under single irri- ciency and stability of crop production gation amounts at different growth stages during different climatic conditions, but of spring rapeseed showed that, 60 mm these increases depend on factors such as single irrigation at flowering stage had seasonal precipitation, rainfall distribution

35 (especially at two critical stages; sowing resources. The study concluded that SI sce- date and heading-flowering stage), type narios maximizing the profit under limited of crop, type of soil, agronomic practices water resources conditions or for a target- including seed rate, fertilizer (amount, ed grain yield of 4 to 5 t/ha should be rec- source and timing use), machinery, weed, ommended for sustainable utilization of pest and disease control and environmen- water resources and higher WP. tal conditions of the specific area. ICARDA has developed methodologies to Optimization of Supplemental Irrigation help farmers determine the right SI man- agement. Determining rainfed and SI pro- Optimal SI in rainfed areas is based on the duction functions is the basis for optimal following three basic aspects (Oweis, economical WP. SI production functions for 1997): wheat are developed for each rainfall zone by subtracting the rainwater produc- • Water is applied to a rainfed crop that tion function from the total water (SI + rain) would normally produce some yield production function. Since rainfall amount without irrigation. cannot be controlled, the objective is to • Since rainfall is the principal source of determine the optimal amount of SI that water for rainfed crops, SI is only applied results in maximum net benefit to the farm- when rainfall fails to provide essential ers. Knowing the cost of irrigation water moisture for improved and stable pro- and the expected price for a unit of the duction. product, maximum profit occurs when the • The amount and timing of SI are sched- marginal product for water equals the uled not to provide moisture-stress-free price ratio of water to the product. conditions throughout the growing sea- son, but to ensure a minimum amount One of the practical problems of SI is that of water available during the critical all the fields may need irrigation at the stages of crop growth that would permit same time in spring. As a result, a very high optimal instead of maximum yield. water supply and large irrigation system is required. A multi-sowing date strategy Increase in crop production per unit land reduced the peak farm water demand or per unit water doesn't necessarily rate by more than 20%, thus potentially increase farm profit because of the non-lin- allowing a reduction in the irrigation system earity of crop yield with production inputs, size and cost (Oweis and Hachum, 2001). particularly with water and its interactions Also, the water demand of a larger area with other input factors. Following English et can be met with the same water supply. al. (1990) and English and Raja (1996) However, optimal sowing dates that mini- analysis, ten years of SI data (1985 to 1996) mize farm water demand do not always on bread and durum wheat were ana- maximize total farm production and/or lyzed to evaluate water-yield relations and water productivity. The outcome depends to develop optimal irrigation schedules for on the crop water requirements and yield various rainfall conditions (Zhang and for each sowing date. Furthermore, selec- Oweis, 1999). Quadratic crop production tion of the optimal strategy is greatly influ- functions with the total applied water enced by the level of water scarcity. (rain+SI) were developed and used to esti- mate the levels of SI water for maximizing yield, net profit and levels to which the CONCLUSIONS crops could be under-irrigated without reducing income below that which would Literature review revealed that the follow- be earned for full SI under limited water ing points could be helpful in assessing the

36 potentials of using SI and single irrigation in (March, April and part of May), so that Iran: crops must often rely on stored soil moisture • Supplemental irrigation and single irriga- when they are growing most rapidly during tion aims at stabilizing yield and pre- May and June. In the wet months, stored venting (and or) minimizing risks due to water is ample, plants sown at the begin- temporal variability of rainfall. It is a ning of the season (October) are in their compensatory action practiced when early growth stages, and water extraction rainfall was less than the long-term aver- rate from the root zone is limited. Usually lit- age for a period of time long enough to tle or no moisture stress occurs during this threaten economical reduction in rain- period. However, during spring, plants grow fed crop production. faster with high evapo-transpiration rate • More than 90% of the country's average and rapid soil moisture depletion due to annual rain falls during October to April. higher evaporative demand conditions. About one-third of the time during 32 Thus, a stage of increasing moisture stress years, the rainfalls below the average starts in the spring and continues until the value of the record. It is generally end of the season. believed that the country is prone to a drought once in 5 to 7 years. Shortage of soil moisture in the dry rainfed Supplemental irrigation could help to areas occurs during the most sensitive save great losses of the yield at this time growth stages (flowering and grain filling) particularly, and to improve the yield of cereal and legume crops. As a result, during average rainfall years. rainfed crop growth is poor and yield is consequently low. The mean grain yield of • Iran has many microclimates. This rainfed wheat in WANA is about one tonne means that the countrywide average per hectare, but ranges from 0.5 to 2.0 rainfall may not necessarily reflect the tonnes ha-1 depending on the precipitation local conditions in a particular rainfed amount and distribution, and on agronom- area. As such, even in a year judged as ic factors such as soil fertility and crop vari- "normal" on the basis of countrywide ety. These yield levels are far below the average, certain rainfed regions may yield potential of wheat (over 4 to 5 be suffering from inadequate precipita- tonnes/ha). Supplemental irrigation using a tion. Therefore, the situations suitable for limited amount of water, if applied during application of SI are more frequent than critical crop growth stages, result in sub- what the countrywide average rainfalls stantial improvement in yield and water may indicate. productivity.

Rainfall in WANA rainfed areas, especially Research results from the Dryland in the dominant Mediterranean-type cli- Agricultural Research Institute (DARI) and mate, is characterized by low annual others, as well as harvest from research sta- amount, unfavorable distribution over the tions and farmer's fields, showed substantial growing season and large year-to-year increases in crop yield in response to the fluctuations. application of relatively small amounts of single and SI water. This increase covers In Maragheh, a major Dryland farming areas with low as well as high annual rain- area in North West of Iran, the annual rain- fall. fall ranges from 202 mm to 504 mm with an Furthermore, using irrigation water conjunc- overall average of 343 mm. Rainfall occurs tively with rain was found to produce more mainly during the winter months wheat per unit of water than if used alone (December- February) and early spring in fully irrigated areas, where rainfall is neg-

37 ligible. In fully irrigated areas water produc- the limitations set by climatic factors, geno- tivity in producing wheat ranges from 0.5 type, and water and nitrogen availability on to about 0.75 kg/m3, one third of that productivity of water: II. Climatically poten- achieved with SI. This difference suggests tial yields and management strategies. Field Crops Res., 38:93-103. that allocation of limited water resources Anderson, W. K., and Smith, W.R. 1990. Yield should be shifted to the more efficient advantage of two semi-dwarf compared to practice (Oweis, 1997). two tall wheat depends on sowing time. Aust. J. Agric. Res., 41: 811-826. In water-scarce areas, water, not land, is Anderson, W. K. 1985. Differences in response of the primary limiting factor to improved winter cereal varieties to applied nitrogen in agricultural production. Accordingly, maxi- the field: I. Climatically potential yields and mizing yield per unit of water, not per unit management strategies. Field Crops Res., area, is a more viable objective for on- 11:363-367. Azari, H., Eslami, K., and Jafarbay, J. 1994. farm water management in the dry farm- Effects of supplemental irrigation on wheat ing systems. Improving water productivity in varieties (Falat and PR1 cultivars) at Gonbad water-scarce areas requires a change in region. Final Research Report, Gorgan the way agriculture is practiced. Agricultural Research Center, (in Persian). Conventional guidelines designed to maxi- Batten, G. H., and Khan, M. A. 1987. Effect of mize yield per unit area need to be revised time of sowing on grain yield, nutrient with a view to achieving maximum water uptake of wheats with contrasting phenolo- productivity. Appropriate policies related gy. Aust. J. Agric., 27: 881-887. to farmer participation and water cost Belson, V. 1999. Study effects of supplemental irrigation and nitrogen rates on increasing recovery are needed to prompt the adop- yield of rainfed wheat varieties. Final tion of improved management options. Research Report, Agricultural Research Center of West Azarbaijan Province, (in Supplemental irrigation and single irrigation Persian). are options with great potential for increas- Bookers Agricultural and Technical Services, Ltd. ing water productivity in rainfed areas. And Hunting Technical Services Ltd. 1975. Scarce water presently used for complete National Cropping Pattern. Ministry of irrigation could be reallocated to supple- Agriculture and Natural Resources, Iran. ment rainfed crops for improved water Caliandro, A., and Boari, F. 1992. Supplementary irrigation in arid and semi- productivity. However, to maximize the arid regions. In: International Conference on benefits of SI, other inputs and cultural Supplementary Irrigation and Drought Water practices should also be optimized. Management. Volume 1. Sep.27-Oct. 2. 1992. Bari. Italy. REFERENCES Campbell, C. A., Selles, F., Zentner, R. P., and McConkey, B. G. 1993a. Available water Absalan, S. h. 2005. Study of supplemental irriga- and nitrogen effects on yield components tion effects and its time on sunflower yield. and grain nitrogen of zero - till spring wheat. Final Research Report, Kohkiloyeh & Agron. J., 85: 114-120. Boyerahmad Agricultural Research Center, Campbell, C. A., Zentner, R. P., Selles, F., (in Persian). McConkey, B. G., and Dyck, F. B. 1993b. Adary, A., Hachum, A., Oweis, T., and Pala, M. Nitrogen management for spring wheat 2002. Wheat productivity under supplemen- grown annually on zero - tillage: Yields and tal irrigation in northern Iraq. On-Farm Water nitrogen use efficiency. Agron. J., 85: 107- Husbandry Research Report Series, No.2. 114. International Center for Agricultural Clarke, J. M. and Simpson, G. M. 1978. Influence Research in the Dry Areas (ICARDA). Aleppo, of irrigation and seeding rates on yield and Syria. 38pp. yield components of Brassica napus cv. Aggarwal, P. K., and Karla, N. 1994. Analyzing Tower. Canadian J. Plant Sci., 58: 731-737. Cooper, P. J. M., and Gregory, P. J., Tully, D.,

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42 CHAPTER III Overview of Crop Water Productivity in Irrigated Agriculture in Lower Karkheh River Basin

Hossein Dehghanisanij1 and Mansour Moayeri2

1Assistant Professor, Irrigation and Drainage Department, Agricultural Engineering Research Institute (AERI), Karaj, Iran 2Irrigation and Drainage Department, AREI, Safi Abad Research Station, Dezful, Iran

43 INTRODUCTION between 1000 and 3000 mm (Dehghanisanij et al., 2006). Agricultural As the population is increasing, additional sector is the main water user in the coun- food is needed (Sekler et al., 1998). try. The irrigated agricultural area in Iran Simultaneously, water is rapidly becoming comprises about 8.4 million ha and scarce, particularly in arid and semiarid presently is using 85.2 billion m3 (92%) of regions of CWANA (Central, West Asia, and total water use (92.5 billion m3). Since the North Africa). Moreover, water demand possibility to increase the water resources from non-agricultural sectors in industry for the agricultural sector in arid and semi- and households, as well as for environmen- arid regions like Iran is limited, improvement tal purposes will keep growing in both of the agricultural water productivity might developed and developing countries. be a more realistic strategy. Karkheh river Irrigated agriculture has been an important basin (KRB) is one of the most important contributor to the expansion of national agricultural zones of Iran located in the and world food supplies and is expected south west of Iran. The objectives of this to play a major role in feeding the growing paper are to provide information on the world population (Cai and Rosegrant, current use of water resources and its pro- 2003). With growing demand for irrigation ductivity in irrigated areas of lower KRB, water and increasing competition among and to assess past research efforts and water-using sectors, the world now faces research needs related to the WP in lower the challenge to produce more food with KRB. less water. This goal will be realistic only if appropriate strategies set for water saving Crop water productivity (WP) is defined as and for more efficient use of water in agri- the crop yield/production (Y) per unit of culture. water consumption, comprising both 'green' water (effective rainfall) for rain-fed Since in many parts of the world water, not areas and both 'green' water and 'blue' land or other factors, is the most limiting water (diverted water from water systems) resources for agricultural production, for irrigated areas. De Wit (1958) was improving agricultural water productivity among the first to do this and he expressed (WP) could be a reasonable strategy to the water use efficiency in kilogram crop overcome water scarcity. Higher crop WP production per cubic-meter of water tran- results in either the same production with spired. The definition of WP is scale- and less water, or a higher production with the user-dependent. Molden (1997) introduced same amount of water. Indeed, the great- the broader term water productivity, for est increases in the productivity of water in analysis of water use at different aggrega- irrigation have not been achieved only tion levels. Molden et al. (2003) refer to this through improved irrigation practices or problem as ''which crop and which drop''. management, but rather through As the numerator, total dry or fresh biomass increased crop yields due to better vari- or harvested product can be used, eties and the use of mineral fertilizers. expressed in physical (kg) or economic Iran is situated in one of the most arid terms ($). As the denominator, there are regions of the world with an average annu- numerous options such as WC which refer al precipitation of about 250 mm, which is to diversion or consumption of irrigation less than a third of the world average. water, such as deficit water applied (DI), Moreover, 179 mm of the precipitation ETc, water diverted (WD), beneficial water evaporates, representing 71% of the total consumption (BWC) and/or non-beneficial precipitation, while the annual potential water consumption (NBWC). Accordingly; evaporation in the country ranges mainly

45 WP1 = Y / DI...... (1) and WP4 is related to the irrigation con- sumptive use coefficient (Burt et al., 1997). The irrigation consumptive use coefficient WP2 = Y / ETc...... (2) (ICUC) is the volume of irrigation water consumed divided by the volume of irriga- WP = Y / BWC...... (3) 3 tion water applied.

WP4 = Y / (BWC + NBWC)...... (4) ICUC = (BWC + NBWC) / WD...... (10)

WP5 = Y / WD...... (5) then;

The values of the water productivity WP4 = Y / (ICUC × WD)...... (11) change based on the hydrological domain at the denominator. Herein, the The pertinence of one or another concept WP value decreases in the sequence WP1 of WP depends on the hydrological to WP5, which could be explained through domain such as crop, field, irrigation unit, different forms of technical efficiency. basin (Playan and Mateos, 2005). The WP1,

Under deficit irrigation (WP1) it has been WP2 and WP3 could be applied at any assumed that all applied water (irrigation scale. However, they are more meaningful and/or rainfall) is used as evapo-transpira- at the field or crop level since they are tion (Hexem and Heady, 1978). The WP2 is related mainly to agronomic aspects of related to farm irrigation efficiency (FIE), the crops related to transpiration. If the which is based on the hydrological domain water that is used is not completely con- and could be related to the water con- sumed within an irrigation unit and the veyance efficiency (Burman et al., 1981) remaining amount cannot be reused with- and to the unit irrigation efficiency in the domain (e.g. evaporation, flow leav-

(Burman et al., 1981). Farm irrigation effi- ing the domain), then WP5 is pertinent. ciency (FIE) is water diversion divided by However, if water is not consumed irrigation requirements or crop evapo-tran- upstream but reused downstream in the spiration (ETc) minus effective rainfall same domain, then WP4 is more appropri- (Molden et al., 1998 ; Burman et al., 1981). ate. Several strategies could be applied for enhancement of crop WP by integrating FIE = WD / (ETc – Rn)...... (6) improved crop varieties and better resources management at different hydro- then; logical domains. WP = Y / [(WD / FIE) – Rn]...... (7) 2 WATER AND LAND RESOURCE AND PRODUCTIVITY The WP3 is related to the irrigation efficien- cy (IE), the volume of irrigation water bene- In Karkheh river basin (KRB), two major agri- ficially used divided by the volume of irri- cultural production systems prevail: rainfed gation water applied (Burt et al., 1997); agriculture in the upper basin of the newly built Karkheh reservoir, and fully irrigated IE = BWC / WD...... (8) systems in the lower parts of the basin. The rainfed areas are well established and then; cover most of the agricultural land in the upper basin, while in the lower basin, WP3 = Y / (IE × WD)...... (9) where irrigated areas were limited before

46 Table 5: Cultivated area, cropping pattern, and average yield for the main crops in irrigated agriculture of KRB (Keshavarz et al., 2005). Crops Cultivated area % of total yield Total (ha ) cultivated area (kg ha-1) Yield (ton) Cereals (wheat, barely and maize) 236700 63.8 2308 546304 Rice 3900 1.1 2686 10475 Forage crops 37500 10.1 9136 342600 Pulses 16000 4.3 1151 18416 Oil seeds 3700 1.0 1229 4547 Vegetables 39100 10.5 18019 704543 Potato 1100 0.3 15755 17331 Orchards 26100 7.0 6674 174191 Sugar beet 2600 0.7 30065 78169 Industrial crops 300 0.1 1703 511 Others 4100 1.1 1088 4461 Total 371100 100 - 1901548 the building of the Karkheh dam, there are Salinity of topsoil fluctuates during the sea- now many irrigated fields and plans for son and generally increases towards the their expansion are underway. Out of the south. The river water quality is suitable for total area of KRB (5.2 million ha), only 1.07 irrigation, though it varies both seasonally million ha are suitable for irrigation and 0.9 and along the river, reaching an EC of million ha are used for dry farming. about 3 dS m-1 near the outlet. The area is suitable for growing a wide range of crops. The most important crops in the irrigated Presently, wheat, maize, alfalfa, and off- area of lower KRB are cereals, forage season vegetables are the most popular crops, rice, vegetables, and sugar beet crops. (Table 5). Vegetables are grown as off-sea- son crops and it includes onion, melon, The agricultural water resources in KRB tomato, and cucumber. consist of both surface and ground water. Out of the total 24.9 billion m3 annual rain- The downstream part of the basin stretches fall in KRB, about 16.4 billion m3 (65.8%) from the Karkheh dam in the north more directly evaporate, 5.1 billion m3 (20.5%) is than 100 km southward, where the Karkheh surface water and 3.4 billion m3 (13.7%) River discharges into the marshlands of infiltrate to . On the average, the Hoor-al-Azim. A number of sub-basins in the total volume of water used by irrigated command area, including Dasht Abbas, agriculture from available water resources Evan, Dusaif, Ardyez, and Bageh, as well as is more than 3.915 billion m3 of which some on the lower plain, are planned for 36.68% originate from underground and over 300,000 hectares expansion of irriga- 63.54% from surface water resources. tion systems including a new irrigation and Karkheh River Basin (KRB) is a relatively drainage network. Agriculture in the down- water scarce area and droughts are stream is dominantly irrigated (now about becoming a frequent feature of this region. 111,000 ha), with annual rainfall ranging The irrigation efficiency in KRB is low and from 300 mm in the north to 100 mm in the the land and water resources are at the south. Soils are mostly young river deposits risk of quality degradation. Irrigation effi- of fine texture with little profile develop- ciency of traditional networks (southern ment and medium to low infiltration rates. KRB) ranges between 14-23%

47 (Mirabolghasemi, 1994) in Dasht June and July. Water used at this station Azadegan. The neighboring basin of the originates from the Dez irrigation network Dez River has higher efficiency rates of 32- that has a very suitable quality for irriga- 37% with consolidated fields of modern tion, with EC of about 0.4 dS m-1 and and networks (Fatemi et al., 1994). Irrigation effi- pH 7.6. The Dezful research station has a ciency is different between the plains and uniform soil type with clay-loam texture at the sub-basins of KRB. It is usually higher 0-60 cm and silty-clay-loam at 60 120 cm where water is taken from underground depth. The pH of the soil ranges between resources. The large amount of water losses 7.5 and 7.9 from the soil surface to 80 cm during conveyance and field application depth, where EC varies between 0.57 and has greatly aggravated resource degrada- 1.1 dS m-1. tion causing salinity in the downstream sub- basins and lowland areas. Obviously, with Research at Safi Abad Station the present management practices, such threats will expand in the future with more Research activities related to soil and severe impacts. water issues in the Dezful region started in Safi Abad station in 1962, when the station Water productivity in KRB is also very low was established. Besides its mandate for with 0.54 kg m-3 (based on the total irriga- agricultural research for irrigated areas in tion water annually used for irrigated agri- lower KRB, the Dezful search station synthe- culture, 3.915 billion m-3, and production of sized research outputs from other research 2.1 million tonnes,), not only compared to stations with similar climatic conditions and potential WP but also to that of other river transferred it to the farmers through local basins in Iran. extension organizations. During the last decade, research activities related to Safi Abad Research Station improvement of water productivity have been mainly on the following topics: Safi Abad Experimental Station near Dezful • Evaluation of irrigation efficiency, is close to the KRB and is the only research • Improvement of different surface irriga- station suitable for conducting studies tion management, related to the irrigated agriculture in lower • Adaptation and evaluation of modern- KRB. Safi Abad research station is located ized irrigation systems, at 32o 16' N and 48o 26' E. It spreads over • Improvement of land preparation, 500 ha and was established in 1963. In • Applying deficit irrigation under different 1985, this station was equipped with a irrigation systems. meteorological station to measure climatic In the following sections, the research data. activities directly or indirectly related to assessment and improvement of wheat, Dezful region has a semiarid climate maize and sugar beet water productivity (Nazemosadat, 1998). The temperature in are reviewed and discussed. this region range between 6.7 and 45.6oC and humidity from 27.4 to 74.5%. The rainy Wheat, Maize and Sugar Beet Water season usually starts in October and con- Productivity in Dezful tinues until the middle of May. The average annual rainfall is about 330 mm. The annu- In northern parts of lower KRB, wheat and al potential evaporation (Keshavarz and barley are usually sown around the middle Ashrafi, 2004) is about 2400 mm, ranging of November. Wheat is harvested during between 50 mm month-1 during December the middle of May, while barley comes to and January and 400 mm month-1 during harvest 2 to 3 weeks earlier than wheat.

48 Based on the Penman-Monteith model was lower, when irrigation water was (Allen, 1998), the wheat and barley irriga- applied at 70 mm evaporation from the tion water requirement in Dezful region is pan, might be due to the shorter irrigation about 592 mm. Based on climatic data of interval. twenty years, the effective rainfall for wheat and barely growing season is about Based on the research by Moayeri and 283 mm. Therefore, 48% of the wheat and Barzegari, (2002) the main cause of low barely net water requirement is provided water productivity in maize fields in Dezful by rainfall, while the rest must be supplied region is the high amount of runoff resulting by irrigation. Furrow and border irrigation from poor irrigation management, long systems are two conventional surface irri- lengths of runs, and improper water alloca- gation systems in Dezful region. Moayeri tion. The impact of different management and Lotfian (2004) showed that wheat systems of furrow irrigation on maize pro- yields under these two irrigation systems duction and water productivity was stud- were not significantly different. However, ied in Dezful research station during 1999- wheat water productivity under furrow irri- 2001 (Moayeri and Barzegari, 2002). Full fur- gation (0.75 kg m-3) was 22% higher than row irrigation (T1) was compared with sin- that under border irrigation (0.61 kg m-3). In gle furrow irrigation under two different irri- addition, the yield was significantly lower gation management of non-alternate irri- when seeds broadcasted compared to gated strips (T2) and alternate irrigated seeds broadcasting plus corrugating strips (T3). The total irrigation water applied (Moayeri and Lotfian, 2004). There was no in T1, T2 and T3 treatments were 16819, significant yield difference between seed- 11642 and 11208 m3 ha-1, respectively, dur- ing rate of 300, 400 and 500 kg ha-1. ing the 1999-2000 and 28411, 18564, and 17533 m3 ha-1 during 2000-2001. The aver- However, wheat yield was significantly age grain yield of the T1 treatment was 7.0 lower when seeding rate was 200 kg ha-1. tonnes ha-1, significantly higher than that There are two growing seasons for maize in of the T2 (5.0 tonnes ha-1) and the T3 treat- Dezful. For the first season, sowing is in early ments (5.0 tonnes ha-1). However, the aver- July and harvesting is in early November. age maize water productivity was almost The net maize water requirement is about the same with 0.31, 0.34 and 0.33 kg m-3 for 705 mm during this season and the effec- T1, T2 and T3, respectively. The average tive rainfall is about 40 mm (Keshavarz et runoff was high in all three treatments al., 2000). For the second season, the comprising about 50% of the irrigation planting date is mid January and the crop water applied. is harvested in early April. During this sea- son, total net maize water requirement is With pressurized irrigation systems, runoff about 461 mm, of which about 116 mm is was found to be very low. Azari (2005) supplied by effective rainfall. studied the impact of drip irrigation system on maize production and water productivi- For maize cultivated in second season ty in comparison with furrow irrigation. He showed that there was no significant differ- applied three levels of irrigation water ence between maize water productivity based on 80, 100 and 120% of the maize when irrigation water was applied at differ- water requirement (ETc) estimated using ent dates based on the accumulated the Penman-Monteith model (Allen, et al., evaporation of 70, 90, and 110 mm from 1998). The irrigation water applied under class A pan (Moayri and Barzegadri, 2000). drip irrigation was significantly less than However, the possible deep percolation that under furrow irrigation (Table 6). The was higher, and the economical efficiency yield of maize was higher under drip irriga-

49 Table 6: Grain yield, irrigation water applied and water productivity of maize under furrow and drip irrigation system. Irrigation Irrigation water Yield Water productivity treatments applied (m3 ha-1) (kg ha-1) (kg m-3) Drip irrigation 80%Etc 5775 9098 1.57 100%ETc 7017 10147 1.45 120%ETc 8264 10536 1.28 Furrow irrigation 7934 21609 0.38 tion compared to that under furrow irriga- applied. Therefore, it can be concluded tion, where irrigation water was almost 3-4 that the maximum WP occurs where deficit times higher. Accordingly, the maize/water irrigation is applied. productivity under drip irrigation was 1.43 kg m-3 on average, which was almost four Wheat WP in Dezful was low in comparison times more than that under furrow irrigation with that in other main wheat producing system (0.37 kg m-3). The drip irrigation with regions of Iran. In Orumieh, Mashhad, and irrigation levels being 80% of the ETc Karaj, wheat WP ranges between 0.5 and requirement showed the highest water pro- 1.8 kg m-3 (Figure 9). ductivity with 1.57 kg m-3. Similar results The measured maize WP from research were reported by Morid (2003), where conducted in Karaj, Mashhad, Orumieh, maize/water productivity under drip irriga- Dezful, and Esfahan ranged between 0.33 tion increased to 1.22 kg m-3 compared to and 2.33 kg m -3. The maximum value was furrow irrigation (0.50 kg m-3). He reported measured in Orumieh (2.33 kg m-3) where 30% runoff under furrow irrigation. yield and irrigation water applied were According to these results, runoff under sur- 9366 kg ha-1 and 4025 m3 ha-1, respectively. face irrigation might be one of the main The maximum irrigation water was meas- factors of the low WP in the Dezful region. ured at Dezful (32558 m3 ha-1) where the Improving the surface irrigation manage- minimum WP was observed. ment to decrease runoff will lead to higher Maximum values of measured maize WP WP. was in the order Orumieh > Mashhad> Esfahan > Karaj > Dezful. The broad range The WP data of wheat and maize from dif- of crop WP might be related to the factors ferent locations in Iran were evaluated. The that influence the soil-plant-water relation- database comprised 10 field experiments ship. For first order explanations of wide conducted by the Iranian Agricultural ranges in crop WP, irrigation water man- Engineering Research Institute during 1998- agement, climate, and soil management 2001 in Karaj, Mashhad, Orumieh, Dezful, are the most effective factors. and Esfahan (Dehghanisanij et al., 2006). Five maize experiments were conducted With the same data, it could be demon- each in a given location and five wheat strated that crop WP can be increased experiments were conducted in three while saving water by reducing the quanti- locations; three in Mashhad and one each ty of irrigation water (Figure 10). in Karaj and Orumieh. According to these results, maize WP in Maximum values of wheat WP was meas- Orumieh was higher when compared to ured in the Mashhad region, where deficit the other regions for any amount of irriga- irrigation was applied during the growing tion water. The quantity of irrigation water season, while the maximum yield was applied to maize in Dezful was almost 60- recorded in Karaj where full irrigation was 200% higher than that in other experimen-

50 tal

Fig. 9. The relationship between measured wheat water productivity (WP) and amount of irrigation water applied (I).

Fig. 10. The relationship between measured maize water productivity (WP) and amount of irrigation water applied (I).

51 sites. Water productivity of maize was 6.9 kg m-3 under fully irrigated furrow decreased when applied irrigation water irrigation (100% of the crop water require- increased to more than 5900 m3. The maize ment). Therefore, deficit irrigated sugar WP was 1.70 kg m-3 with 5900 m3 irrigation beet under drip irrigation had a higher WP water. We concluded that this value of WP compared to that under full irrigation. Total as optimum level for maize production. This irrigation water applied for 100% crop should be considered for inclusion in the water requirement under drip irrigation was recommendations of cropping system at 6898 m3 ha while that under furrow irriga- the national level. A maximum crop WP will tion was 13237 m3 where 21% of irrigation often not coincide with farmers' interests, water was lost as runoff. Accordingly, in the whose aim is to maximize land productivity case of sugar beet cultivation as well as or economic profitability. It calls for a shift that of maize, the main reason for the low in irrigation science, irrigation water man- WP is poor irrigation system management. agement and basin water allocation to move away from 'maximum irrigation-maxi- CHALLENGES AND OPPORTUNITIES mum yield' strategies to 'less irrigation-maxi- FOR IMPROVING WP mum crop WP' policies. As already discussed, low WP in irrigated Sugar beet is another major crop in the irri- area of KRB is mostly due to poor irrigation gated area of northern parts of lower KRB, management. In other words, water pro- which is usually planted in early September ductivity in the KRB could be substantially and harvested by the end of April. The net increased by improving on-farm irrigation water requirement of sugar beet is 459 mm management, introducing precision irriga- out of which 122 mm is provided by effec- tion, decreasing deep percolation and tive rainfall (Keshavarz et al., 2000). runoff in traditional irrigation systems, allo- cation of irrigation water, based on actual Malekzadeh et al. (1999) studied the WP of crop water requirement, introduction of sugar beet under three irrigation systems of new varieties, adjusting cropping patterns furrow, sprinkler and center-pivot irrigation and integrating appropriate agronomic systems in Dezful. The irrigation efficiency of practices in the crop production system furrow, sprinkler and center-pivot irrigation together with suitable institutional setups system ranged between 10-20%, 71-74% and policies. Besides, drought-resistant vari- and 57-64% respectively. Irrigation efficien- eties play an important role in increasing cy under center-pivot irrigation was lower WP. Hence, genetic improvement of irrigat- than that under sprinkler system maybe ed crops could be a part of the effort. because of higher evaporation during the Another important area of interventions is irrigation. In sugar beet field under furrow the study of the interactions between soil irrigation, runoff losses were 30-35% of the fertility and water management at the water applied. In addition, deep percola- plant-, plot-, field- and basin-level. It is tion expected additional losses. believed that the key to the realization of Accordingly, sugar beet WP was 5.89, 12.20 this hypothesis is the involvement and par- and 10.24 kg m-3 for furrow, sprinkler and ticipation of farmers, local communities as center-pivot irrigation system respectively. well as government organizations and insti- Sugar beet water productivity was also tutions responsible for water and agricultur- higher under drip irrigation compared to al development in the basin. that under furrow irrigation. Sugar beet WP was 17.2, 15.2, and 13.1 kg m-3 when 50, 75, The followings approaches are suggested and 100% of the crop water requirement to improve the water use in agriculture and was applied through drip irrigation while it to enhance WP, which needed to be con-

52 sidered in research and extension activities: 3. Use of pressurized irrigation systems for 1. Optimization of irrigation efficiency, agri- optimized water consumption cultural inputs and planting system • Determination of the potential area for • Modifications in cropping pattern to expansion of pressurized irrigation sys- optimize water use. tems. • Genetic improvements of agricultural • Extension of pressurized irrigation systems crops with higher WP and selection of in potential areas to replace surface irri- high yielding varieties and their release gation methods. to the farmers. • Expansion of micro-irrigation systems • Comparative studies on irrigation effi- due to its better water conservation and ciency in consolidated and non- consol- other advantages. idated agricultural lands. • Advanced management of pressurized • Integrated management of irrigation irrigation systems in order to prevent water and fertilizer application. salinization and degradation of irrigation • Optimized water consumption through land. modified planting dates in some irriga- • Study and convert traditional surface irri- tion areas to avoid drought effects dur- gation methods in orchards to different ing ripening. micro-irrigation systems. • Introduce and application of early- • Production of vegetables and summer maturing crop varieties with high initial crops in greenhouses with micro-irriga- growth rate. tion systems to increase yields and • Reduction of evaporation losses from reduce water consumption. the soil surface using different mulches, • Studying the best irrigation schedule for sub-irrigation, subsurface irrigation, different pressurized irrigation systems absorbents and agronomic methods. based on cropping pattern and crop • Reducing non-beneficial percolation water requirement. and runoff. 4. Use of optimized deficit irrigation tech- 2. Improving surface irrigation systems nique to increase WP in irrigated lands. • Development of land leveling and land Although parts of the objectives and consolidation plans and estimation of approaches discussed above have been appropriate farm sizes. addressed by previous research efforts • Dissemination of raised-bed furrow and conducted on-stations, there are big gaps alternate furrow irrigation methods to between these findings and their practical farmers. application by the farmers. Little is known • Reuse of return flows in furrows and bor- as to why farmers have hardly adopted ders. technically viable and improved technolo- • Dissemination of methods leading to gies. This is believed to be primarily due to faster water flow in furrow and border inadequate interaction between scientists, irrigation to reduce deep percolation extension staff, and farmers so far. There is and direct evaporation losses. a need to integrate biophysical and socio- • Dissemination of modern techniques in economic research to better understand surface irrigation (e. g. surge irrigation). why farming communities have adopted • Use of controlled drainage sub-irrigation or disregarded technologies to optimize methods especially in the areas with subsurface drains. water use efficiency and WP. • Study and expansion of subsurface irri- gation methods.

53 REFERENCES In Water conservation, reuse, and recycling, Proceeding of an Iranian-American work- Allen RG, Pereira LS, Raes D, Smith M. 1998. shop, National Academic of Science, USA. Crop Evapotranspiration: Guidelines for Keshavarz A., Ashrafi S. 2004. Challenge of Computing Crop Water Requirements. Water and food and related priority Irrigation and Drainage Paper No. 56. FAO, research in Karkheh river basin. Proceeding Rome, 300pp. of Water, Agriculture and Future Challenge Azari A. 2005. Evaluation of drip irrigation system Conference, Dezful, Iran. (in Farsi) on maize cultivation. MSc. Dissertation, Malekzadeh M., Dabag G, Orazizadeh M., Shahid Chamran University, , Iran. (in Moayeri M.1999. Evaluation of population Farsi) and damage of sugar beet pests and dis- Burman R.D., Nixon P.R., Wright J.L., Pruitt W.O. ease under three irrigation systems of furrow, 1981. Water requirements in Design and sprinkler and center pivot. Research report. Operation Farm Irrigation Systems, Edited by Agricultural Engineering Research Institute. M.E. Jensen, ASAE, St. Joseph, Michigan, (In Farsi) 1981 Mirabolghasemi H.1994. Evaluation of irrigation Burt C.M., Clemmens A.J., Strelkoff T.S., Solomon efficiency in some traditional networks of K.H., Bliesner R.D., Hardy L.A., Howell T.A., Iran (including the southern parts of the Eisenhauer D.E., 1997. Irrigation performance Karkheh River). Proceedings of the 7th measures: efficiency and uniformity. J. Irrig. Seminar of Iranian National Committee on Drain. Engrg. 123, 423-442. Irrigation and Drainage. IRNCID Publication Cai X., Rosegrant M.W. 2003. World water pro- No.7 (in Farsi). ductivity: Current situation and future Moayeri M., Barzegari M. 2002. Irrigation sched- options. In Water Productivity in Agriculture: uling of spring-maize under Khozestan cli- Limits and Opportunities for Improvement. mate condition. Research report. Kijne JW, Barker R, Molden D (eds.). Agricultural Engineering Research Institute. Comprehensive Assessment of Water (in Farsi) Management in Agriculture Series 1. Moayeri M., Lotfian B. 2004. Assessment of the CABI/IWMI, Wallingford/Colombo; 301-309. best seeding rate and water productivity of De Wit C.T. 1958. Transpiration and crop yields. wheat under different surface irrigation sys- Verslag. Landbouwk. Onderz. 64.6. Institute tems. Annual research report. Agricultural of Biology and Chemistry Research on Field Engineering Research Institute. (In Farsi) Crops and Herbage. Wageningen, the Molden D. 1997. Accounting for water use and Netherlands, 88pp. productivity. SWIM Paper 1. International Dehghanisanij H., Keshavarz A., Heydari N. 2006. Irrigation Management Institute, Colombo, Agricultural water consumption manage- Sri Lanka. 16 pp. ment in Iran considering aridity and drought Molden D. Murray-Rust H, Sakthivadivel R, incidences. Eighth International Conference Makin, I. 2003. A water-productivity frame- on Dryland Development 25-28 February, work for understanding and action. In Water Beijing, China Productivity in Agriculture: Limits and Fatemi M.R., Shokrollahi A., Shiroy M.H.1994. Opportunities for Improvement. Kijne JW, Impacts of land consolidation on irrigation Barker R, Molden D (eds.). Comprehensive efficiency in Dez Irrigation Network. Assessment of Water Management in Proceedings of the 7th Seminar of Iranian Agriculture Series 1. CABI/IWMI, National Committee on Irrigation and Wallingford/Colombo; 1-18. Drainage. IRNCID Publication No.7 (in Farsi). Molden D., Sakthivadivel R., Perry C.J., de Hexem R.W, Heady E.O. 1978. Water production Fraiture C., Kloezen W.H. 1998. Indicators for functions for irrigated agriculture. Ames, Comparing Performance of Irrigated Iowa: State University Press. Agricultural Systems. Research Report 20. Keshavarze A., Dehghanisanij, H., Alizadeh A. International Water Management Institute, 2000. National Documentary of Crop Water Colombo, Sri Lanka. Requirement in Iran, Vol. 1. Morid A. 2003. Study on the yield and yield Keshavarz A., Ashrafi S., Heydari N. 2005 Water components of maize under surface and allocation and pricing in agricultural of Iran. drip irrigation system with different seeding rate. Master thesis, Dezful Azad University.

54 Dezful, Iran. Seckler D. Molden D., Barker R. 1998. Water Nazemosadat M. J. 1998. Persian Gulf Sea scarcity in the twenty-first century. Surface Temperature as a Drought International Water Management Institute, Diagnostic for Southern Iran. 10(3):10-12. Colombo, Sri Lanka. Playan E., Mateos L. 2005. Modernization and optimization of irrigation systems to increase water productivity. Agric. Water Manage. 76 (3): 139-159.

55 56 CHAPTER IV Overview of Soil and Water Resources and Salinity in Lower Karkheh River Basin

Nader Heydari1 and Seyed Ali Mohammad Cheraghi2

1Assistant Prof. & CPWF Karkheh River Basin Coordinator, Irr. and Drain. Dept., Iranian Agr. Eng. Res. Ins. (AERI), Agr. Res. and Edu. Org. (AREO), Ministry of Jihad-e Agriculture, Karaj, Iran 2National Salinity Research Center (NSRC), Yazd, Iran

57 INTRODUCTION sugarbeet, sugarcane, potato, silage corn, cotton, alfalfa, barley, and chickpea was Agriculture plays an important role in the in the range of 0.56-1.46, 0.59-1.28, 0.31, . It accounts for 18% of the 1.45-3.0, 6.46, 0.73, 1.48, 0.56, and 0.18 Gross Domestic Product (GDP), 25% of kg/m3 respectively (Heydari et al., 2006b). employment, supply of more than 85% of However, there is no literature on measure- food requirements, 25% of non-petroleum ment and assessment of WUE in the LKRB. exports, and 90% of raw materials used in Based on rough estimates concluded from various industries (Keshavarz et al., 2003). farmers field visits and questionnaires on The climate of Iran is one of great extremes crop yield and applied water, WUE of irri- due to its geographic location and varied gated wheat, for instance, in this area is topography. Approximately, 90% of the quite low and is about 0.6 kg/m3. country is arid and semi-arid. The summer is hot with temperatures in the interior reach- Karkheh River Basin (KRB) is one of the ing as high as 55°C. Water resources man- important basins in Iran regarding water agement in such extreme environments is resources both in dryland and irrigated a great challenge. agricultural production systems. Water in KRB is limited and becoming scarce as Despite large reliance of the country on population and demand are increasing. agriculture, especially irrigated agriculture, The productivity of rainfed agriculture is water resources required for agricultural very low; conventional irrigation manage- production is very limited. Currently more ment is poor; cropping systems are sub- than 93% of water consumption (84 billion optimal; and policies and institutions are 3 m ) is used for irrigation of 8.1 million ha. weak (Anonymous, 2007a). Despite these Agriculture, in general and irrigated agri- constraints, Iran's agricultural strategy iden- culture in particular, is the greatest con- tifies water productivity improvement as a sumer of water among the country's eco- top priority. nomical sectors; also the major losses of water occur in this sector. The challenges for the rural households in the upper catchments of the KRB are simi- With the growing demand for water for lar to the ones in other dry areas. As agri- industry and municipalities, combined with cultural options are limited, wheat and environmental concerns, there will be less extensive sheep rearing dominate the water for agriculture in the future. landscape. Agricultural output is usually Therefore agricultural water use efficiency low and unstable, mainly due to resource has to be increased. degradation and unpredictable droughts (Anonymous, 2007b). Irregular rainfall on Based on the latest agricultural statistics, poorly vegetated hill slopes results in severe the country produced 67 million tonnes soil erosion, downstream flooding and sedi- agricultural products from 84 billion m3 of mentation. Consequently, the lifetime of water consumed. Therefore, currently the the Karkheh Dam reservoir is dwindling rap- country's average WUE is almost 0.8 kg/m3 idly. These environmental constraints com- which seem quite low in comparison to the bined with their economic problems make world's value. Based on farmer's field stud- this southwest corner of Iran one of the ies were conducted in five regions in the poorest in the country with a very high out country namely Kerman, Hamedan, migration rate (Anonymous, 2007c). Moghan, Golestan, and Khuzestan (Heydari et al., 2006a), the crop Water Use KRB has been selected as one of the nine Efficiency (WUE) for the irrigated wheat, bench mark basins of the CGIAR

59 Challenge Program on Water and Food tions showing how important this province (CPWF). One of the CPWF ongoing proj- had been throughout the history of agricul- ects addresses interventions for the tural development in Iran. The existence of improvement of on-farm agricultural water ancient renowned structures such as productivity in KRB. This project is carried Cheghozanbil water purifier, water wills at out jointly by the International Center for , shipping along the lower Karun Agricultural Research in the Dry Areas River and many other heritages have (ICARDA) and Iranian Agricultural Research made this province an attractive place for and Education Organization (AREO) The the tourists. objectives of the project are to develop biophysical interventions to improve the It has been estimated that approximately farm and basin water productivity and the 4.1 million hectares of arable land exists sustainable management of the natural within the borders of Khuzestan Province, resource base, and to develop appropri- of which roughly 2.2 million ha have the ate policies and institutions supporting the potential for irrigation. A study on 1.78 mil- project interventions to help the poor com- lion ha of land in the Khuzestan province munities for the improvement of their shows that with due regards to the pro- income and livelihoods. Moreover, the posed crop patterns, a potential of devel- project aims at strengthening and enhanc- oping 1.2 million ha of irrigated crops out ing the capacity of National Agricultural of 1.78 million ha exists. In Table 7 some Research Services (NARS) of Iran. information on the Khuzestan province is provided. This review paper provides an overview of the soil and water potential of the Lower The vast Khuzestan plain is mostly com- KRB (LKRB) and the salinity and water log- posed of alluvial deposits and small aggre- ging constraints to agricultural production gate sediments of the main rivers and and agricultural water productivity (WP) in numerous tributaries. The fertility of the soil this part of the basin. It also addresses the gradually decreases from the North to the soil and water potentials and agricultural South of the plain, in as such that the soil in production issues in the Khuzestan Province the South of the province is heavy with of Iran because LKRB is administratively large contents of saline and sodic minerals governed by this province. Therefore, WP in and very difficult to drain. the LKRB will be affected by the physical, socio-economic, administrative organiza- Climate and Soils tions, and policy issues in this province. The Khuzestan Province is influenced by THE KHUZESTAN ENVIRONMENT the low pressure Mediterranean Front, the Siberian high pressure Centre, and the low The Khuzestan Province is located in the pressure hot Arabian and North African    desert winds, thus making it one of the South West of Iran at latitudes 29 56 , 33      hottest and most arid regions in the world. 5 South and Longitudes 47 , 42 , 50 22 . It encompasses an area of approximately Elevations vary from zero to 4000 meters 67130 km2. The Zagros mountain range is above sea level. The average annual rain- located in the South and East of the fall is approximately 265 mm and the aver- province dividing it into two sections. The age annual amount of evaporation is 2500 mm. The average temperature in the five major rivers of Iran – Karun, Dez,  Karkheh, Jarrahi, and Zohreh (Hendijan) – region is 25 Centigrade. Total agricultural flow through this fertile plain. Along these areas of the Khuzestan province is 3.3 mil- rivers are the remnants of ancient civiliza- lion ha. The area of surveyed lands, non

60 Table 7: Some information on Khuzestan province, Iran Khuzestan province area 6.7 M ha Ratio of province to total country area 4% Number of plains 50 Area of plains 3.7 M ha Area of mountainous areas 2.9 M ha Maximum altitude in the northern plains 150 m asl Minimum altitude in the Persian Gulf areas 2 m asl Province population 4.5 million Ratio of urban residence 64.8% Ratio of rural residence 35.2% Percent of population working in Agriculture sector 17% surveyed lands, and the wetlands in the Ground Water Resources province are 2, 1.3, and 0.64 million ha, respectively (Public Relation Office, 2006a) Ground water resources are often found in the form of springs or wells in the region. An Surface Water Resources exact study carried out on the alluvial lakes in the Karkheh, , Dezful, The average inflow of the five major rivers Shushtar, , , Iezeh and in the Khuzestan province is approximately plains showed that the existing 31.3 billion m3, which is equivalent to a third hydro potential among the stratum is 3 of the total surface water in Iran. The aver- approximately 2 billion m . Currently 831.3 3 age flow rate is approximately 950 m3/s. million m is being abstracted by 3039 wells of which 739.6 million m3 is being utilized in 3 In the province more than 8.9 billion m3 of the agricultural sector; 64.9 million m is water is used by the irrigation sector, of being used for drinking purposes; and 27.1 3 which 93% is abstracted from surface flows million m is being used by the Industrial and the rest from ground water sources. sector.

The average amount of water consump- The Khuzestan Water & Power Authority tion per hectares is approximately 17,200 (KWPA) m3 and the average efficiency rate is less The existence of vast water and soil than 30%. In Table 8 and (Figure 11) infor- resources in the Khuzestan province and mation on basin area and flow discharge the exigency of utilizing these resources of the major rivers in Khuzestan plain are necessitated vast and thorough studies to provided respectively. A comparison of the be carried out in the region. On May 29, water resources and sedimentation in the 1960, the National Parliament and Senate Khuzestan province to the whole country is passed a bill by which the Khuzestan Water also provided in Table 9. and Power Authority (KWPA) was officially As can be seen from Table 8, out of the established in order to carry out the proj- eight rivers/gauging station in the ects in the Khuzestan region. The Khuzestan Khuzestan Province Karkheh river stands in Water and Power Authority is the sole cus- fifth, fourth, and fourth ranking position in todian of water resources in the province regard to basin area, average annual dis- and therefore responsible for the alloca- charge, and average annual flow param- tion, operations and protection of this nat- eters respectively. ural resource with the ultimate goal of opti- mal development and operation.

61 Table 8: Information on basin area and flow discharge of the major rivers in Khuzestan plain River Station Basin Year of Annual discharge Annual flow (MCM) Area establishment (km2) of station Avg. Prob. Max Min Avg. Prob. Max Min 80% 80% Karoon Gotvand 34425 1953 390.0 257.2 828.0 187.0 12301 8111 26112 5897 Dez Dezful 17813 1956 249.0 158.1 554.9 120.0 7851 4985 17499 3784 Great Ahvaz 60737 1970 634.4 428.6 1443 269.0 20006 13516 45506 8483 Karoon Karkheh Paypol 43183 1961 180.3 104.6 397.9 56.9 5687 3299 12548 1795 Allah Jokank 2260 1956 20.0 10.9 54.6 4.7 629 344 1723 149 Maroon Behbahan 3740 1953 50.1 26.2 120.2 11.9 1581 825 3790 374 Zohreh Dehmolla 11703 1955 80.8 37.4 213.3 21.2 2549 1180 6727 669 Shavoor Shavoor - 1959 16.6 11.7 24.1 10.0 523 369 760 315 Total 986.8 658.6 1986 455.4 31121 20768 62624 14361

Table 9: A comparison of the water resources and sedimentation in the Khuzestan province to the whole country (Public Relation Office 2006b) Item Total dams of Dams in the the Country Khuzestan province Total area of river basins of the Dams in the country 240,000 km2 91,000 km2 The total capacity of the country's reservoirs 25.6 BCM 15.5 BCM (60% of the total) Annual sedimentation in the reservoirs 180 MCM/yr 92 MCM/yr (51% of the total)

Fig. 11. Annual water yield of total rivers in the Khuzestan plain and the Karkheh River.

62 Large rivers such as the Karun, Dez, SOIL AND WATER SALINITY IN IRAN Karkheh, Jarrahi, and Zohreh and the numerous tributaries, springs, and streams Salinity stress poses one of the most serious along these rivers flow downstream from threats to food production and sustainabili- the Zagross mountain, through the fertile ty of natural resources in Iran. Salt-affected Khuzestan plain and down into the Persian soils are present in many parts of the coun- Gulf. In Table 10 information on irrigation try, particularly in the Central Plateau. This and drainage networks development proj- Plateau is surrounded by two main ranges ects of the KWPA in the entire Khuzestan of high mountains running northwest to province is given and in Tables 11 and 12 northeast (Labors) and northwest to south- information on total numbers of irrigation ern parts and southeast (Zagrous networks in the Khuzestan province and Mountains). the irrigation and drainage networks in the Average yields of common crops vary lower KRB are provided. according to locations and climatic condi- tion. However, they are generally lower Challenges in the Soil & Water than the potential yields expected. There Development of Khuzestan Province are a number of natural, technological, and man-made reasons for the relatively The followings are identified as key chal- low yields obtained under farmers' condi- lenges in the province: tions. Natural problems are quite varied in different parts of the country, but they are • Shortage of investments, especially mostly due to climatic conditions (such as investment from private sector low precipitation rates and high evapora- • Lack of a proper comprehensive agri- tive demand), water availability and its cultural plan in the province quality, and soil conditions. Among the • Problems with exports major natural obstacles which prevent the • Unemployment achievement of high yields in Iran is the • Water withdrawal in upstream areas of salinity of soil and water. It is estimated that the basin in areas where salinity is present, average • Socio-cultural factors limiting agricultural yields losses may be as high as 50% (Siadat, productions 1997a) • Lack of emphasis on the fisheries sector. Extent and Types of Saline Soils in Iran The large dam reservoirs, large rivers and lakes located in the Khuzestan province Even though most of the salt-affected soils offer a good opportunity for fisheries devel- in Iran are found in the Central Plateau, opment, but unfortunately not much atten- the problems of salinity and sodicity are tion is paid to this activity in this province. present in other parts of the country also. It is estimated that some 10% of the total With regard to shortage of investments, the area the country suffers from salt accumu- following areas of investments can be rec- lation. However, considering that man- ommended: made salinization has been occurring and • Investments required for the execution intensified in the last decades, due to the and completion of irrigation networks expansion of irrigated farming, an increase • Delay in execution of the irrigation net- in the total area of salt-affected soils is to works construction and increase of the be expected. In fact, more recent esti- estimated costs mates put this area at around 18 million ha, including the salt marshes of the Central Plateau (Siadat, 1997b)

63 Table 10: KWPA irrigation and drainage networks development division projects (Public Relation Office, 2006c) Watershed Area Under Study Ready for Under construction Operations (ha) Phase Phase construction Supply and Main I II conveyance networks Karkheh 328434 13900 115995 94076 258474 48403 56060 Karoon 251503 62400 11000 72657 93492 30381 75065 Dez&Shavoor 236400 56700 7500 18000 154200 Marun & Allah 84323 27569 27569 56754 Zohreh&Boneh Basht 90300 22000 46852 52000 9200 12248 Total 990960 155000 134495 241154 105984 354327

Table 11: Total irrigation networks in the Khuzestan province based on the river basins (Public Relational Office 2006d) Basin Area Study Ready Under ExecuteOperation (ha) Phase Phase to Supply and Main I II execute Conveyance Networks Karkheh 314534 115995 94076 258474 48403 56060 Karoon 197103 35000 64192 93492 43611 54300 Dez&Shavoor 185000 55000 130000 Marun&Allah 80823 27569 49594 22025 31229 Zohreh&Boneh Basht 75300 10000 45852 52000 7200 12248 Sugarcane project 130000 40000 78000 Fishery 35000 17000 18000 Total 1117760 100000 115995 288689 453560 133239 379837

Table 12: Irrigation and drainage networks in the lower KRB (Public Relational Office 2006e) Networks Area Study Ready to Under Execute Operation (ha) Phase Phase construct Supply and Main I II Conveyance Networks Hamidieh&Ghods 15700 15700 Zamzam 2500 2500 Avan 13000 13000 Koot&Hamooddy 7800 7800 Arayez, Dosalegh, Bagheh 51575 35427 51575 16148 Azadegan plain (East) 22334 4229 22334 18105 Chamran 76553 63300 13253 76553 Koosar 14150 14150 14150 Azadegan Plain (West) 36826 36826 36826 Azadegan Plain (development) 52695 52695 52695 Hamidieh (development) 4341 4341 4341 North of Hamidieh 17060 17060 Sum 314534 115995 94076 258474 48403 56060

64 Since extensive parts of the country have The man-made causes are mainly due to arid to semi-arid climate, soils belonging to poor irrigation management and water- arid lands such as Aridisols are widespread. logging problems mostly occurring in the Saline soils of this order in Iran belong to irrigation networks developed under regu- both Hapiosalids and Aquisalids great lated waters like dams. Increased applica- groups. The latter soils are mostly bordering tion of marginal waters for irrigation without the playas and have a groundwater level required management has also increased within one metre from the soil surface. this problem in recent years. Overall, the Haplosalids, however, are located away man-made causes include the poor water from these playas where groundwater management, over-exploitation of ground- depth is below one metre depth (Siadat, water poor land preparation, fallowing 1997c).For both of these great groups, and overgrazing and sea-water intrusion. Typic, Gypsic, and Calcic sub-groups are found in different areas. In all, a Salic hori- Salinity Research and Management in Iran zon is present with varying thickness depending on parent material and use. For the last forty years, major efforts have focused on the solutions to salinity prob- There are other types of saline soils in Iran, lems in Iranian agriculture. Much of such which present problems of high salt con- research was initiated in early 1960's by the tent but lack a Salic horizon according to Soil Institute (Presently called Soil and the definition of USDA Soil Survey Staff Water Research Institute, SWRI, Tehran, (Siadat, 1997d). Such soils are either Alfisols Iran) in cooperation with the Soil Fertility or Inceptisols having a Natric horizon with Project of the FAO. high concentration of sodium. These saline soils belong to two soil sub-groups, namely During the last two decades, most of the Natrixeralfs and Natric camorthids with SAR studies on saline soils and water resources >13 or ESP >15. Geographic distribution of used in agriculture have been carried out these soils follows the same pattern as the by the SWRI and Agricultural Engineering groundwater containing sodium carbon- Research Institute (AERI), Karaj, Iran. Other ate and sodium bicarbonate in low ter- governmental organizations such as the races of the river valleys and flat slopes of Ministry of Energy, the Ministry of Jihad and the rivers fans. Kovda in 1970 reported the some faculties of agriculture have also presence of these saline soils in the north- been engaged in certain studies. ern and eastern parts of Iran as well as in In recent years, salinity research has got the Central Plateau (Siadat, 1997e). more attention by the policy makers. This led to the establishment of National Salinity Causes of Soil Salinization in Iran Research Center (NSRC). NSRC is the youngest, but very closely linked, institute The existence of large areas of saline/sodic to the work relating to salt-prone land and soils in various parts of Iran reflects the fact water resources degradation and their that there are many factors affecting this management. The center started working phenomenon. Indeed, the causes of soil in 2000 in the Yazd Province, which is most salinity can be divided in two categories, seriously affected by salinity relate prob- namely, natural or primary causes and sec- lems. The mandate of the center has four ondary or man-made causes. major aspects (Cheraghi, S.A.M. 2004):

The natural causes includes geological • Research on the causes and manner of and physiographic conditions, Climatic development of saline and sodic soils conditions and Salt transport by water. • Determination of the effects of saline

65 and brackish water on soil and crop sodicity are alleviated from soil profile production through leaching. Therefore, common agri- • Implementation of research to deter- cultural research practices required for the mine the most suitable methods of crop region are being conducted in that station production under saline, saline-alkali, and there is not much space for salinity and sodic soil conditions research in that area. • Cooperation in research to determine the varieties and plant genetic Based on a summary list of the research resources resistant to salinity and flood- topics conducted in the country on salinity ed conditions management by individual research insti- tutes1 , till year 2004 almost 115 research Besides its main campus and research projects are conducted specifically on facilities in Yazd, NSRC has several regional salinity issues. These research projects networks addressing the unique problems cover some provinces or regions in the of salt-prone land and water resources in country facing with soil and water salinity specific agro-ecological areas. These net- hazard e.g., Yazd, Golestan, Fars, works are in Khuzestan (through Ahwaz Khurasan, Khuzestan, Markazi, Hormozgan Agricultural Research Center stations, e.g. (Boshehr), Moghan, Azarbaijan, Esfahan, Shavoor research station), Khurasan, Fars, and Qom. However, very limited salinity Esfahan, Golestan, Boshehr, and Qazvin. In research projects have been conducted in addition, the NSRC has several linkages LKRB and on salinity-WP related issues in this and collaborative work with national and basin or even in whole country nothing international organizations. much is done. Out of 115 research topics, almost half are crop-based and the other The Shavoor Agricultural Research Station is half are confined specifically to soil and one of the major agricultural research sta- water subjects. So there is a balance in this tions of Ahwaz Agricultural Research regard. Center in Khuzestan province. This station was established in 1936 and is located In the field of soil leaching and reclama- near Ahwaz city, the center of Khuzestan tion, so far, most of the research findings Province. This station was initially named as have been about leaching requirements Soil Reclamation Research Station. The typ- and, to a lesser degree, the type of suit- ical research in the beginning was con- able amendments materials such as sulfur, fined to soil leaching and reclamation, and gypsum, and sulfuric acid. Accordingly, the effects of drain spacing on groundwater most extensive remedial action which has level, and application of amendments been actually applied in certain limited (e.g. Gypsum, Sulfure, Organic matters, Bio areas is salt leaching by irrigation water. amendments, etc.) This has been carried out in Khuzestan and Fars provinces in governmental projects. The following areas of research are promi- nent in this research station Farmers and private sector involved with • Use of marginal waters in drained lands. agriculture, however, are not known to • Use of organic matters and its effect on have any planned programs for leaching reclamation of saline- sodic soils. or used any of amendments. Some tradi- • Research on application of macro and tional practices, though, may be interpret- micro fertilizers under soil and water ed as salinity control measures. For exam- salinity conditions. ple, in many areas, farmers apply a heavy At present, following the installation of irrigation at the time of planting. This con- drainage system in the centers, salinity and tributes both to the storage of water in the

1The list was collected from the relevant institutes (AERI, SWRI, and NSRC) by the first author 66 lower soil layers and the removal of some SALINITY IN KARKHEH RIVER BASIN salts from the top layer. Besides, the com- (KRB) mon observation that in many salt-affect- ed agricultural fields irrigation water is KRB is located in the west to south - west of applied in excess of plant water require- Zagroos ranges in Iran. KRB is located ment may be interpreted as a traditional between 56, 34´-58, 30´ North latitude intermittent leaching practice. Therefore, it and 46, 06´-49, 10´ longitude. The area of is reasonable to state that intermittent the basin (inside Iran) is 50764 km2, out of leaching is commonly used by the farmers. which 27645 km2 are mountains and 23119 km2 are plains and hills. The mountainous Till now salinity research has covered the areas of KRB are mostly in the eastern and followings areas: central parts. The plains are mostly in the • Extent of salt affected soils Northern and Southern parts covering • Characteristics of salt affected soils in almost 45% of the basin area. Based on Iran hypsometric studies, 75% of the basin is • Methods used to ameliorate salt affect- located in altitudes of 1000-2000 and 0.6% ed soils of the basin is above 2500 m altitude. • Crop productivity potentials of salt affected soils The Karkheh River arises from the conflu- • Productivity of saline water used in dif- ence of numerous large and small tributar- ferent parts of Iran ies including the three large rivers, namely • Values of saline water in Iran as Gamasiyab, Ghareh so, and Kashkan. The drainage water and groundwater Karkheh River has various names along its • Quality of saline water with respect to route and is locally best known as the salts and other contaminants in Saymareh river at the point where the drainage water and ground water Gamasiyab and Ghareh rivers combine and later at the point were the Kashkan It is also fair to say that little has been done River flows into the main waterway, it is in the following areas and thus more work known as the Karkheh River. The river ulti- is needed: mately flows into the Hawr-al-Azim (HAA) • Environmental aspects of salt-affected wetland that borders Iran and Iraq. soils • Crop productivity potentials of salt- After Pay Pole hypsometric and slope of affected soils the basin decreases and gently passes • Economic evaluation of the manage- HAA wetland. In Table 13 physiographic ment options for the salt-affected soils characteristics of KRB are provided. Based • Response of communities to salt affect- on general hydrological classification of ed soils basins in Iran, the KRB is considered as one • State of knowledge on above aspects of the Sub-basins of the Persian Gulf Great in KRB Basin. From the North, the basin is limited to • Different approaches used to irrigate Sirvan, Ghezel Ozan, and Gharachai rivers, with saline water from the west to the basins of Iran-Iraq • Response of communities to irrigate with Border Rivers, from the East to the Dez river saline water basin and from the South to part of west- • Economic aspects/evaluation of irriga- ern border of Iran. Among the important tion with saline water cities in this basin, Malyer, Nahvand, • State of knowledge on above aspects Toyserkan, Kangavar, Songhor, Kamyaran, in KRB Kermanshah, Kerend, Khoramabad, and Sosangerd are most notable.

67 The pattern of precipitation in KRB is affect- ed by Mediterranean regime. It means that the dry season is coinciding with summer and rainy season match with cold months. The rainfall in the basin is classified as win- ter rains and then autumn and spring rains. The annual precipitation of the basin is 219 mm in Hamidieh (Southern part of KRB) to 765 mm in the northern part.

Based on climatic maps, the hottest areas of the basin are located in its southern parts and are surrounded by the 25oC Iso- temperature (Isohyets) contour. The cold- est areas of the basin are located in alti- tude higher than 3000 m, and are mostly located in the North and North-east of the basin and are surrounded by the 50oC Isohyets contour map.

Evaporation in KRB varies between 1800 and 3600 mm depending on altitude. For example it is around 3560 mm in Abdol - Khan Station in an altitude of 40 m in LKRB. Almost 79% of annual evaporation occurs from almost May to September.

Water resources of KRB are both surface and ground water. In 1994, the share of (%) agricultural water consumption from these rive (%) (km) (km) resources was 3.915 billion m3. The agricul- tural water consumption untill the comple- tion of the on-going water works can be 21 0.49 0.33 437 1.8 1324.5 590.25 21.5 increased to 7.433 billion m3 (90% increase). The water resources of the basin in general have a good quality. However, the quality of ground water in the Southern plains (m) of river (km) (km) Length Wide deteriorates to some extent. Potential of 1439.2 4.66 0.36 0.19 630 2.11 16.5 246.32 61.18 surface water resources of KRB is 7.374 bil- 3 lion m . In wet years it can be doubled and ) elevation (%) slope slope of of river coefficient meter rectangle 2 in dry years it can be as low as half.

Agricultural water withdrawn in KRB is 3.956 (km billion m3 (in year 1994). Out of which 37% is 42239.3 1548.06 5. supplied from ground water and 63% from surface water resources.

The rate of surface to ground water resources consumption in sub-basins of KRB is different. The Gharasou sub-basin in the North has the greatest rank (75.2%) in HAA: Hawr al Azim wetland Table 13: Physiographical characteristic of KRB (Mahab-e Ghods, 1996) Basin Area Mean Slope Hamidieh to HAA*) Gross* Average Length Gravelliest Peri- Equivalent KR -Hamidieh Station KR - Pay 45654.8 PoleStation The inner area (from 5150 17.31 0.102 0.02 0.004 25 1.17 300 96.79 53.21

68 ground water consumption. The Kashkan duction under both dry farming and irrigat- sub-basin (also in the North) has the high- ed conditions are issues of crucial impor- est rank (93.9%) of surface water consump- tance to increase per capita income of tion. From the point of view of the quanti- farmers in the basin. ties the most of ground water is withdrawn in Gamasiab, followed by Gharasou sub- Two major agricultural production systems basin, in the Northen part of KRB. In the prevail in the KRB. The dry-land system pre- whole KRB the highest consumption of sur- vails in the upstream and the fully irrigated face water resources is in the Southern areas are located in some part of (Lower) KRB. Based on the 1994 statistics, upstream and all parts of downstream of out of different plains of KRB, Azadegan the KRB. The dryland areas are well estab- plain (Dasht e Azadegan, DA) with 662 mil- lished and cover most of the basin agricul- lion m3 water consumption is the greatest tural lands, occupying 894,125 ha, whereas consumer of water in the basin. This plain is irrigated lands occupy 578,862 ha but also the greatest consumer (660.2 million expected to expand by additional 340,000 m3) of surface water in the basin. The ha following the construction of the Nahavand plain in the northern (Upper) Karkheh reservoir Dam (Anonymous, KRB is the greatest (215 million m3) con- 2007d) sumer of ground water resources in the basin. KRB is one of the main basins in the coun- try's rank. Despite overall favorite potentials Based on 1994 statistics, out of 4157.4 mil- in respect to climate, soil, and water lion m3 consumed water, 2504.6 million m3 resources in the basin, agricultural water (60%) was from surface water and 1653 mil- productivity in the lower and downstream lion m3 (40%) from ground water resources. areas of the KRB is very low. This is mainly Out of total consumption, share of rural, due to the harsh climatic environment in urban, industry and mining, and fishery the southern part and lack of sound agro- consumption were 1.23, 3.93, 0.32, and nomic, water and salinity management 0.35% respectively. The share of agricultural practices. KRB is a water shortage area water consumption in this year was 94.17. and droughts are becoming a permanent Therefore, from aspects of water resources feature of this region. Due to water short- consumption, the KRB is completely an age and degradation of land and water agricultural basin and the industrial and resources, livelihoods of rural communities mining consumptions were just 0.32% of are at stake. Considering the present pace total water consumptions. From urban of deterioration, the situation will become water consumption point of view, even worse in the years to come. On the Kermanshah plain with 58.5 million m3 other hand, there is a great potential for water consumption and from the view- the improvement of land and water pro- point of industrial water use this plain with ductivities in the KRB. Therefore KRB is well 7.73 million m3 has the greatest consump- suited to be a major area for develop- tion. From agricultural point of view, ment-oriented research activities to be Azadegan plain (DA) with 642.6 million m3 implemented under the Challenge water consumption is the higher consumer Program on Water and Food (CPWF). KRB of water in the KRB. provides a unique opportunity for the CPWF to make an impact through KRB encompasses one of the poorest improvements in land and water manage- regions of Iran because it has very low ment, which in turn will improve the liveli- infrastructure and is severely affected by hoods of millions of rural poor living in this the 1980-'88 war with Iraq. Low food pro- basin. The problems of KRB have a great

69 similarity with other basins located in the water salinity are major problems. This area similar hydrological conditions. Therefore is planned for further development follow- lessons learned here will be equally appli- ing the model of adjacent Dez irrigation cable to these basins. district.

However, in the lower Karkheh river basin Waterlogging and soil salinity are the major (KRB) heavy soil texture and recharge from threats to water productivity and sustain- upstream areas cause natural condition for able agricultural production in the LKRB water logging and is more induced by low and thus guidelines based on sound and irrigation efficiency of irrigated agriculture relevant research are urgently needed. In in the region. The available soil data indi- addition to the national food security cates that the majority of arable lands in objective, improving the well-being of the KRB possess various degrees of limitations agricultural communities in the lower (either individually or in combination). region are exceptionally important to mini- Salinity, water-logging, lack of soil organic mize socio-economic problems regarding matter, soil structural deterioration, and low local migration of farmers and security infiltration rate caused by compaction are issues along the Iran-Iraq border communi- the main factors limiting economic and ties. sustainable crop production in the irrigated lands of lower parts of KRB (Anonymous, Owing to the relatively good quality of 2007e) Karkheh river water (EC= 0.79-2.5 dS/m) and favorable climatic condition for agri- The Karkheh Dam was completed in 1999 cultural activities in the lower KRB, efficient and became operable in 2001. The main use of available arable lands and good objectives of the dam are to produce quality irrigation water will have significant Hydro-electric power (1000 GW/h/year), effect on the economy of the region with flood control, and supply of regulated flow positive national implications. for irrigation of more than 340,000 ha of lands on down stream side of the dam. In the LKRB, because of the differences in These arable lands are located in different factors affecting agricultural water produc- plains situated in the lower parts of KRB tivity in the northern and southern parts, (Mahab-e Ghods, 2005) two distinct regions can be identified. They are the areas in the northern part and the At present there are no modern irrigation southern parts of LKRB. and drainage networks under operation within the dam coverage area and agri- In the northern part, there are not much culture is not yet fully developed. However, limiting factors regarding soil and water the government started to study and con- quality. In this area improving farmer's skills struct irrigation and drainage networks, or and application of appropriate farming modify the traditional irrigation systems. The systems can improve water productivity drainage outlet of the area, which also is a greatly. Limitations in water supply and basin outlet, is the HAA Wetland in Iran-Iraq excess irrigation water losses (mainly in common border. Irrigation efficiency and earthen canals) also causes lower water water productivity in the lower parts of productivity of crops. Therefore, demon- KRB,like in the upper parts, are low. In this stration of new farming systems e.g., pres- area, despite the availability of irrigation surized irrigation, land preparation methods water, agricultural water management is (raised bed, double row cropping, etc.), poor and because of high water table and could be useful for improving water pro- high potential evaporation rate, land and ductivity. In this part successful introduction

70 and implementation of new farming sys- generally divided into southern and north- tems and technologies in accordance with ern parts. The northern district, which is agricultural service center could be an called Pay-e Pole, ends up to Karkheh effective way for improving water produc- Diversion Dam in Hamidieh area; hence tivity. Two major problems in this area are the Southern district mainly accommo- the large farm size and low population dates the municipal facilities. Karkheh River density. diverts towards northwest of the region near the city of Hamidieh and eventually In the southern parts of LKRB, mainly Dasht- joins Hawr Al-Azim wetland. Dasht-e e Azadegan (DA) plain, available data Azadegan (DA) region is located at the and surveys showed that the problem of furthest southern part across the delta of soil salinity is magnified due to lack of farm- Karkheh River 20 km west the city of ers' knowledge, skills and unavailability of Ahwaz. Total area under study in this new and improved farming practices. In research was almost 200,000 hectares, of general, the main cause of soil salinity in which 95000 hectares spread over the cur- the LKRB is high water table, often less than rent civil projects of Dasht-e Azadegan 2.0 m, usually 1.2-3.0 m below the soil sur- region. This plain is located between 47' face, If left alone, the problem is likely to 55'' to 48' 30'' E and 31' 15'' to 31'45'' N and worsen, especially with the current plans its height above sea level varies between 3 for expansion of irrigation networks. to 12 m. In the southern parts, it seems that in addi- DA is covered with fine sediments carried tion to the factors limiting water productivi- by Karkheh River and with an almost even ty (e.g., farmers skill, new farming system, surface and mild slope expanding towards etc.) the major limiting factors are water the West and the East flanks. The general logging and soil and water salinity. This slope of the plain is also towards southwest. problem will worsen in future with expan- The area of study included the lands sion of irrigation networks. At present, between Karkheh river and Karkheh Noor despite construction and operation of river i.e, main DA plain, eastern district of main drains in the area, the situation has DA, western district of Dasht-e Azadegan, not improved. This is mainly due to some northern part of Karkheh river, falls on the technical problems (e.g., slope of drain) left bank of Karkheh river and other farm- and also the problems concerning the out- lands along this river. let. Gravity drainage to outlet is not possi- ble and it needs pumping. Environmental DA comprises of three subdivisions (or concerns regarding drainage to Hawr Al towns) namely Sosangerd (in the center), Azim wetlands are also another problem. It , and Bostan. A fourth community is claimed that the government is studying is identified by the Rufai town, located in a plan to construct a main drain and carry the lower part of lower KRB region and drained water to the Persian Gulf by gravi- near the Hawr-Al Azim Wetland, which is ty (Anonymous, 2007f). However, research the outlet of KRB main basin. Total popula- topics (both on-farm and experimental) tion of the DA is about 160,000, 65% of related to water table management and which are living in the towns. The total salinity control will help much to improve in number of villages at present is 180, a num- productivity of agriculture in this area. ber that was nearly half (300) before the war against Iran. Dasht-e Azadegan Plain Based on the existing statistics, the total This region stretches from Karkheh Sofla number of the villages in DA and Hamidieh sub-basin to Hawr-Al-Azim wetland and is

71 is 219 of which 96 have been abandoned responding to July) and the minimum of 43 now. These villages are located in 7 dis- mm occurs in Dey (corresponding to tricts, namely, Nahr-e Hashem, Bostan, January). Based on the climatological Bani-Saleh, Homeh, Shorfeheh, Hamd and data of past ten years at Sosangerd and Howeyzeh. The main cities of the region Howeyzeh stations also based on the bio- include Hamidieh, Sosangerd, Howeyzeh climatic map of Mediterranean region (by and Bostan. The existing statistics indicate FAO and UNESCO), and despite the exis- that the weather is hot in summer with mild tent 260 dry days in a year, Dasht-e and short winter. Annual mean tempera- Azadegan has not been classified as ture of the region is 23.1 ºC. The maximum Accentuated Sub-Desertic Area. The total daily temperature in the warmest months rainfall in Sosangerd and Bostan is 180 mm of the year (Tir and Amordad according to and 200 mm respectively. There is a weath- solar calendar corresponding to June, July er station in Bostan. The agricultural service and August) is 43 ºC and the minimum centers also are equipped with rain daily temperature in the coldest month of gauges. Table 14 presents some of the the year (Dey according to solar calendar influential factors in climate and evapora- corresponding to January) is 5 ºC. The tion state of Dasht-e Azadegan region. average precipitation in the area is 175 mm over the past decade. The wettest Current crops in Dashte-Azadegan include month of the year is Azar (corresponding cereals such as wheat, barely, rice, and to October) with 44.1 mm and the driest ground cereals; vegetables such as melon, months are Khordad, Tir, Mordad and watermelon, tomato, cucumber, eggplant, Shahriver (corresponding to the period okra, lettuce, cabbage, carrot, radish, and from March to late September) when there onion; legumes such as beans; fodder for is almost no precipitation. Annual mean livestock such as alfalfa, barely, corn and evaporation in this area is 2005 mm. The Sudan grass. More than 78% of agricultural maximum evaporation 304 mm is in Tir (cor- production in Dasht-e Azadegan region is

Table 14: Some metrological parameters and Evapotranspiration values for different months in Dasht-e Azadegan Plain (Hamidieh station), (Mahab-e Ghods 1993 a). Month* Temperature ( C) Precipitation **ET Average Min Average Max Average (mm) (mm) Day 5 16.4 10.7 41.3 42.7 Bahman 6.9 19.7 13.3 24.1 62.5 Esfand 11 24.8 17.9 23.3 105 Farvardin 15.2 30 22.6 17.7 150 Ordibehesht 19.6 36.6 28.1 6.5 234 Khordad 22 41.8 31.9 0.0 299.2 Tir 23.7 43.2 33.5 0.2 303.6 Mordad 22.8 43.2 33 0.0 279.8 Shahrivar 19.2 41.2 30.2 0.7 235 Mehr 14.8 35.1 25 4.2 155.5 Aban 10.1 26.6 18.3 11.5 88.1 Azar 6.7 19.1 12.9 45.5 49.5 Average 14.8 31.5 23.1 175 2004.9 * Based on Iranian Calendar ("Day" coincides almost with January) **ET is calculated from the Blaney- Cridlle or adjusted Pruit equation

72 dominated by grains-mainly wheat and At present despite of the construction and barely (Anonymous, 2007 G.), (Mahab-e operation of main drains in the area, in Ghods, 1992). This is because of the poor some areas the system is not properly func- quality of a vast area of this region due to tioning. This is mainly due to some techni- saline sodic soil with high toxicity, which cal and excavation problems (i.e., improp- makes cultivation of other productions er slope of drain lines) and also the prob- almost impossible. lems concerning the outlet (Based on Regional Agricultural Organization experts The reasons why farmers prefer wheat culti- and authorities and information from local vation currently are that there is limited visits in 2004). Gravity drainage to outlet is water supply, the assured returns from it not practically possible and pumping is (guaranteed purchase of the produce by required. Environmental impacts regarding the Government), and security problems in drainage flow directly into the mentioned the region (wheat needs less labor, less irri- wetland is also another concern that gation, and less maintenance). should be considered.

The source of irrigation is mainly the water Salinity in the Dasht-e Azadegan pumped from the river. There are also limit- ed irrigation networks in the region (mainly Land classification studies for Dasht-e pumping from river to the canal). In the Azadegan region showed that approxi- Hamidieh area (the faraway area to the mately 33,334 ha of this region belong to border and the beginning of the plain, land classes I and III. Tables 15 and 16 pres- near to Ahvaz City) there is also a diversion ent different land classes and sub-classes dam. The main canals and drains are along with irrigation potentials for Dasht-e mainly constructed or under completion Azadegan region. The main constraints on (Main irrigation and drainage canals in these lands and the classified lands Koot and Hamoodi in Construction units of include: salinity and alkalinity of the soil, 1 &2 are under construction). But, there is high levels of saline groundwater, soil per- hardly any secondary or tertiary canals or meability and drainage restrictions in the drain lateral. area. In fact, almost all of the farmlands in this region have salinity and alkalinity prob- The main problem of agriculture in this lems. region are water logging and salinity. The results of semi-detailed studies indicate Water logging followed by soil salinity that approximately 80% of farmlands of occurs in a certain period. For example, in Dasht-e Azadegan region are lands with wheat cultivation in DA, planting is taken both low or high salinity and alkalinity. up in early November. In late November, Table 17 displays the extent of the prob- the first irrigation for land preparation is lem. given. The harvest is in late May. Deep per- colation losses of irrigation during this peri- Overall, out of 91,470 ha of Dasht-e od causes the water table to rise. The peak Azadegan region of water table rise is in February. The salinity • 1% or 70 ha have no salinity and sodicity (EC) of ground water and irrigation water limits; in this area is 6-9 dS/m and 3 dS/m respec- • 16% or 14599 ha have moderate salinity tively. Water table depth is between 0-1.2 and sodicity; m. Operation of Main Drains is started • 27.4% or 25040 ha have high salinity and recently (in 2003) and their outlet is Hor-al sodicity. Azim Wetland (Anonymous, 2007 H). • 2.2% or 2040 ha are lands with varying rates of salinity and sodicity.

73 Table 15: Classes and Sub-classes of land classification in the Dasht-e-Azadegan Plain (Mahab-e Ghods 1992a). Class and Sub-class Class Sub-class Area (ha) (%) Area (ha) (%) II 64.98 6.84 - - IIA 2670 2.81 IIAS 2674 2.81 IIAW 267 0.30 IIASW 878 0.92 III 26836 28.26 - - IIIS 2042 2.15 IIIA 13752 14.48 IIIW 1046 1.10 IIIAS 4902 5.16 IIISW 170 0.18 IIIAW 2513 2.65 IIIASW 2411 2.54 IV 1534 1.61 - - IVS 1084 1.14 IV/V 450 0.47 V 34801 36.63 - - VA 26726 28.13 VW 6050 6.37 VAW 2025 2.13 VI 24940 26.25 - - VIA 23350 24.58 VI/M 1050 1.10 VI/R.B 540 0.57 VA+III 391 0.41 391 0.41 Total 95000 100 95000 100

Based on the sample profiles tests, the ture of this soil and higher infiltration rate. saline surface soil of Dashte-Azadegan However, thick cation layers may give region can be divided into saline soil and unfavorable responses to agricultural activ- saline-sodic soils. The characteristics of ities. Basically, in saline, sodic or saline- these two types of soil are: sodic soils with concentrated soil solutions do not bring any major change to the soil a) Saline-sodic soils: much of Dasht-e structure, but after flushing the soluble salts Azadegan is consisted of this type of soil and exit of the soil cations with an increase which has the following characteristics: of sodium ions ratio, it is expected that due • an EC more than 4 dS/m to its permeability and clay dispersion the • an ESP more than 15% soil structure will be damaged. Thus care • pH less than 8.5 should be taken in terms of the irrigation High saline concentration in soil solution water and correctives qualities during soil creates concentrated absorbed cation correction period. layers and thus enhances the quality struc-

74 Table 16: Classes and Sub-classes of irrigable lands in the Dasht-e Azadegan Plain (Mahab- e Ghods 1992b). Land classes Area (ha) (%) Sub-class Area (ha) (%) I 5396 5.86 - 5396 5.86 II 17933 18.88 IIA 10907 11.48 IIW 1046 1.10 IIS 1102 1.16 IIAS 2365 2.48 IIAW 1879 1.99 IIASW 634 0.67 III 33011 34.75 IIIW 1950 2.05 IIIA 18073 19.02 IIIS 9525 10.03 IIIAS 3072 3.23 IIIAW/A 391 0.42 IV 1084 1.14 IVS 1084 1.14 V 35536 37.40 VA 26926 28.34 VW 5720 6.02 VAW 2890 3.04 Other 2040 2.15 - 2040 2.15 Total 95000 100 - 95000 100

Table 17: Salinity and Sodicity classes of Soils in the Dasht-e Azadegan Plain (Mahab-e Ghods 1992c). Salinity and Sodicity EC (dS/m) ESP (%) pH S.A.R Area (ha) (%) class

S0A0 <4 <10 <8.5 <8 70 0.07 S1A0 4-8 <10 <8.5 <8 11670 12.28 S1A1 4-8 10-15 8.5 8-13 2935 3.10 S2A0 8-16 10 8.5 8 1150 1.21 S2A1 8-16 10-15 8.5 8-13 3055 3.22 S2A2 8-16 15-30 8.5-9 13-30 21588 22.72 S3A2 16-32 15-30 8.5-9 13-30 20825 21.92 S3A3 16-32 30-50 9-9.5 30-70 7926 8.34 S3A2 S2A2 8-32 15-30 8.5-9 13-30 391 0.41 S4A3 32 30-50 9-9.5 30-70 11540 12.15 S4A4 32 50 9.5 70 11810 12.43 Other - - - - 2040 2.15 Total - - - - 95000 100

75 b) Saline soil: the smaller portion of this approaches the end its water quality suf- region is covered by this type of soil with fers. It is evident that any irrigation with the following characteristics: such water quality will enhance the soil • an EC more than 4 dS/m salinity in the lands downstream of Karkheh • an ESP less than 15% River. • pH less than 8.5 Dasht-e Azadegan soil studies showed that more than 99% of the area of the region The unstable salinity limit in these lands have been faced with either high or low facilitates the soil reclamation compared salinity and sodicity for a long time. Overall to saline-sodic soil type lands. Only leach- natural and man-made factors are ing of the soil can reclaim the soil and involved in soil quality of the region. reduce the salinity. High levels of Dasht-e- In order to study the reaction of the soils to Azadegan groundwater resources and salinity and sodicity reduction through deep percolation losses from the current leaching in the region, the leaching tests irrigation systems impose numerous restric- were carried out using the amendments at tions on irrigation development in the area. 33 stations. Table 18 presents the location, The ground water level under area ranges series, salinity and sodicity classes, some from 1 to 3 m. The lands are usually com- physical characteristics, applied water posed of heavy surface texture with low or resources and their quality in soil reclama- very low permeability rate that are more in tion experiments for Dasht-e Azadegan form of wetlands, also the runoffs resulting region. Table 19 also shows the results of from precipitation and irrigation of the soil chemical analysis before and after upstream lands remain on the surface for a leaching experiments as an example. long time. Soil in the region has a heavy texture on the surface and deeper layers and soil permeability is of slow or very slow CONCLUSIONS AND rate, which weakens the performance of RECOMMENDATIONS the irrigation system and offsets the leach- ing of saline lands. • Soil salinity and water logging, in addi- tion to the other sources of inefficiencies As indicated before, saline-sodic soil consti- in agricultural WP improvements, are the tutes a vast area of Dasht-e Azadegan major limiting factors in the LKRB. region and this relatively increases the sodi- • These problems are due to physical um ions ratio to calcium and magnesium characteristics of the region (soil, ions, therefore, make sodicity of the soil hydraulic gradient), but are mainly and as a consequence intensifies clay dis- man-made problems and can be man- persion and destruction of the soil struc- aged by proper measures, including ture. In addition to the above factors, infrastructure activities (hardware) and other influential parameters that contribute to greater extent by proper field water constantly to the soil salinity are irrigation of management (software) measures. the lands in the region with saline water • In the hardware part: Irrigation and and considerable quantities of saline min- drainage networks are developing in erals carried along by river streams. These the area, but till now unfortunately it is soluble salts are washed away by river flow mainly limited to the main canals/drains especially during floods and this brings sev- and the lower order canals/drains that eral thousand tonnes of salt and mud to are necessary for the implementation of the region. Wastewaters of the lands also proper water management are lacking. enter Karkheh River system and as it • In the software part: many studies and

76 Table 18: Location, series, salinity-Sodicity class, some physical characteristics, water resources, and their quality in the soil reclamation (leaching) studies of Dasht-e Azadegan Plain (Mahab-e Ghods 1993b). Row Exper- Soil series Basic infiltration rate (cm/hr) iment Value Description (m) class water Depth of Hydraulic Class of applied Water table depth Impermeable layer conductivity (km/d) Salinity and Sodicity 1 1 & 2 Hofel S3A2 0.5 0.98 4 0.36 & 0.6 Medium Slow C3S1 2 3 & 4 Karami S3A4 1.5 0.43 3.5 0.14 & 0.22 Medium very Slow C4S2 3 5 & 6 Karami S4A4 0.5 0.65 4 0.18 & 0.22 Slow Rapid C4S3 4 7 & 8 Finikhi S2A1 1.0 0.75 4 2.22 & 3.44 Very rapid C4S2 5 9 Yazd No S4A3 4 0.06 4 1.74 Rapid C3S1 6 10 & 11 Abo Hamizeh S4A1 0.75 0.09 4 1.51 & 2.42 Very rapid Rapid C3S1 7 12 & 13 Koot S2A2 0.5 0.30 4 0.93 & 1.56 Rapid Medium C4S4 8 14 Mojrieh S4A2 4 0.13 4 0.37 Slow C4S2 9 15 & 16 Lolieh S4A2 2.5 0.27 3.5 0.24 & 0.27 Slow C4S2 10 17 ABo Hamizeh S2A2 0.75 1.09 3.5 1.32 Rapid C4S2 11 18 Karkheh S4A3 0.75 1.04 3.5 0.33 Slow C4S3 12 19 & 20 Golbahar S3A2 1.0 0.05 3.5 1.42 & 1.77 Rapid C3S1 13 21 Karami S4A3 1.5 0.04 3.5 0.21 Slow C3S1 14 22 & 23 Hoveizeh S4A3 1.5 0.88 4 0.59 & 1.0 Medium C4S3 15 24 & 25 Ahmad Abad S2A2 0.75 0.01 3.5 0.25 & 0.26 Slow C3S1 16 26 & 27 Ahmad Abad S4A3 1.5 0.04 4 0.32 & 0.43 Medium Slow C4S2 17 28 & 29 Sarieh S4A3 0.5 0.04 3.5 0.32 & 0.82 Medium Slow C4S4 18 30 & 31 Hamidieh S3A3 0.75 1.26 3.5 0.32 & 0.43 Slow C3S1 19 32 & 33 Koot S3A3 1.5 - 3.5 0.17 & 0.22 Slow Very slow C4S2 Source of applied water is Karkheh river

network designs (in the project level) fer from a clear and well-defined strate- are conducted in the area by consult- gies and policies for water manage- ant engineers and other expert organi- ment in the Khuzestan province, and zations. But these are mostly classic especially in the L-KRB, where 2/3 of the studies and application of new country's water recourses flows. approaches and tools such as use of • Wetland interactions with the upstream proper models relevant to the plant, irrigated agriculture developments farm, system, and basin levels are lack- could be optimized and managed ing or not applied sufficiently. This weak- using proper planning and coordination ness, even in the comprehensive plans inside and with outside of the country. of the basin, is also evident. • Water limitations (required for the agri- • The detailed studies are done mainly at cultural lands in the LKRB and all of the the project level. There is no detailed or aforementioned issues) suggest that we semi-detailed studies at the basin level. should efficiently use water in the KRB • Responsible organization in the region or and the policy of WP improvement in even in the headquarters in Capital suf- the KRB should be given higher priority.

77 Table 19: Result of soil analysis before and after salt leaching from the soil profile Station: L.1 *(Mahab-e Ghods 1993c). Applied water (cm) Soil Depth (cm) EC (dS/m) SAR 0 0-25 28 23.4 25-50 25.5 16.6 50-75 24.2 21.5 75-100 24.2 16.8 100-150 26.4 15.5 25 0-25 18.5 17.2 25-50 25.3 - 50-75 23.6 15.6 75-100 22.9 16.5 100-150 7.3 18.4 50 0-25 8.3 9.9 25-50 15.8 - 50-75 22.9 17.2 75-100 26.4 19.3 100-150 5.1 19.9 75 0-25 7.6 5.8 25-50 10.8 9.2 50-75 24.5 17.6 75-100 24.8 20.9 100-150 8.9 20.8 100 0-25 8.3 12 25-50 10.1 11.6 50-75 11.1 14.5 75-100 19.3 13.5 100-150 - 19.3 *Characteristics of soil profile in location of L1 were: Soil series: Hofel; Soil texture: Silt-Loam; Soil salinity- sodicity class: S3A2; Water table depth: 0.5 m, Hydraulic conductivity (K): 0.98 m/d; Depth of imperme- able layer: >4 m, Basic Infiltration rate 0.6 cm/hr (low), Salinity class of applied water: C3S1 (EC=1.75 dS/m, SAR= 1.8, pH= 7.6) (Mahab-e Ghods 1993d).

• There is no doubt that research activities farmers are necessary. related to water-table management, • The KRB reflects in many aspects the , irrigation water man- problems of water management in agement, selection of suitable crop other basins in the region. Accordingly, varieties, and improved agronomic it is intended to link the work in KRB with practices will help improve agricultural the Euphrates and Amu-Darya river water productivity and farmers liveli- basins, which have been postponed to hood stalled in this region. Water log- the next phase of the CGIAR Challenge ging and resource salinity are major Program on Water and Food (CPWF). threats to water productivity and sus- tainable agricultural activities in the lower KRB region and sound solutions that are adoptive and adaptive by

78 REFERENCES ects on soil and water salinity. Jihad Engineering Services (1994). Studies of Abvarzan (1993). Report of drainage and soil watershed management in the Karkheh reclamation studies, Tertiary irrigation and basin, hydrology report, Ministry of Jihad-e drainage network plan of Hamidieh area Agriculture, Deputy of watershed, planning (Right bank of Karkheh Noor), Ministry of office. Jihad Engineering Services company, Energy, Khuzestan Power and Water 1994, Vol. I (in Persian). Authority, Abvarzan consultant Engineers, Keshavarz, A., Heydari, N., Ashrafi, S., (2003). 1993, Vol. I, Tehran, Iran (in Persian). Management of agricultural water con- Abvarzan (1990). Report of drainage and soil sumption, drought, and supply of water for reclamation studies, Tertiary irrigation and future demand. 7th Int'l Conference on drainage network plan of Hamidieh area Sustainable Development and Management (Right bank of Karkheh Noor), Ministry of of Dry-lands in 21 century, Tehran, Iran, 4-17 Energy, Khuzestan Power and Water Sep. 2003. Authority, Abvarzan consultant Engineers, Khuzestan Power and Water Authority (2000). 1990, Vol. I, Tehran, Iran (in Persian). Study of Karkheh river salinity trend, office of Agricultural statistics of Khuzestan province Basic studies of water resources, Khuzestan (2005). Estimate of cultivated areas and agri- Province Water Authority, Khuzestan, Iran (in cultural products of towns (Dasht-e Persian). Azadegan), Khuzestan province, cropping Mahab-e Ghods (2005). Optimal allocation of year 2003-2004, Agricultural organization of Karkheh river water resources, Studies of Khuzestan, Planning deputy, 2005, vol. II. (in agricultural and agricultural economics, Persian). Mahab-e Ghods consulting Engineers, 2005, Anonymous (2007). Some observation and infor- Tehran, Iran (in Persian). mation collected during different field visits Mahab-e Ghods (2004). Systematic and com- from lower KRB during the CP-KRB project. prehensive in optimal allocation of Karkheh Cheraghi, S.A.M. (2004). Institutional and scien- river water, report of planning for Karkheh tific profiles of organizations working on River, Mahab-e Ghods consulting Engineers, saline . In: Taha, F.K., Ismail, 2004, Tehran, Iran (in Persian). S., Jaradat, A. (Eds.), Prospects of Saline Mahab-e Ghods (1996). Hydrological studies of Agriculture in the Arabian Peninsula: Hawr-Al Azim Swamp, Irrigation and Proceedings of the International Seminar on drainage Plan of Karkheh, Mahab-e Ghods Prospects of Saline Agriculture in the GCC consulting Engineers, 1996, Tehran, Iran (in Countries, 18-20 March 2001, Dubai, United Persian). Arab Emirates, pp. 399-412. Mahab-e Ghods (1993). Soil reclamation studies Deputy of soil and water (1988). Studies of soil of Dasht-e Azadegan development, leaching and reclamation, Shahid Chamran Irrigation and drainage Plan of Karkheh, irrigation and drainage network plan, Phase Mahab-e Ghods consulting Engineers, 1993, I, Jihad-e Sazadegi organization of Tehran Tehran, Iran (in Persian). province, deputy of soil and water, 1988, Mahab-e Ghods (1992). Phase I studies of agri- Tehran, Iran (in Persian). cultural economic and current situation of Dez Ab, (1992). Studies of soil leaching and Dasht-e Azadegan Plain, Mahab-e Ghods reclamation of Hamidieh, and Ghods plains, consultant Engineers, 1992, Vol. 4-5, Tehran, Dez Ab consulting Engineers, 1992, (in Iran (in Persian). Persian). Mahab-e Ghods (1992). Studies of agricultural Heydari, N. A. Eslami, A. Ghadami, A. Kanoni, development plan of Dasht-e Azadegan, M.E. Asadi, M.H. Khajehabdollahi (2006), " Irrigation and drainage Plan of Karkheh, Determination of water productivity of some Mahab-e Ghods consulting Engineers, 1992, major crops in different regions of Iran". Res. Tehran, Iran (in Persian). Rep. No. 84/988, Iranian Agr. Eng. Res. Ins., National Salinity Research Center (2005). List of Karaj, Iran (in Persian). salinity research projects in National salinity Iranian agricultural engineering research institute research center (2005). Iranian agricultural engineering Public Relation Office (2006). Presentation on research institute completed research proj- soil and water potentials of Khuzestan Province, Khuzestan Water and Power

79 Authority, Ministry of Energy. Soil and water (1999). Irrigation and drainage Siadat, H. (1997) Salt-affected soils of Iran, network of the areas in Shahid Chamran Country report presented in seminar on salt- plan, Study phases of I, II, report of affected soils, Sep. 1997, Cairo, Egypt. Infiltration, layering, hydraulic conductivity, Soil and water (2001). Irrigation and drainage Part I, Ministry of Energy, Khuzestan Power network of the areas in Shahid Chamran and Water Authority, Soil & water consultant plan, Study phases of I, II, report of land clas- Engineers, 1999, Tehran, Iran (in Persian). sification, Part II, Ministry of Energy, Khuzestan Soil and water (1999). Irrigation and drainage Power and Water Authority, Soil & water network of the areas in Shahid Chamran consultant Engineers, 2001, Tehran, Iran (in plan, Study phases of I, II, report of Persian). Infiltration, layering, hydraulic conductivity, Soil and water (1999). Irrigation and drainage Part II, Ministry of Energy, Khuzestan Power network of the areas in Shahid Chamran and Water Authority, Soil & water consultant plan, Study phases I, II, report of land classifi- Engineers, 1999, Tehran, Iran (in Persian). cation, Part II, Ministry of Energy, Khuzestan Soil and water research institute (2005). List of Power and Water Authority, Soil & water soil and water research institute completed consultant Engineers, 1999, Tehran, Iran (in research projects on soil and water salinity. Persian).

80 CHAPTER V Causes and Management of Salt-Prone Land Degradation in Lower Karkheh River Basin

S.A.M. Cheraghi1, Y. Hasheminejhad2, and N. Heydari3

1Director, National Salinity Research Center (NSRC), Yazd, Iran 2National Salinity Research Center (NSRC), Yazd, Iran 3Agricultural Engineering Research Institute (AERI), Karaj, Iran

81 INTRODUCTION for agricultural production. However, salin- ization of land and water resources has Salt-prone land and water resources are become a serious threat to efficient use of major impediments to the optimal utiliza- these valuable resources. It is estimated tion of crop production systems in many that out of the total 6.7 Mha of the arid and semi-arid regions of the world province, 1.2-1.5 Mha (18-22% of total including Iran (Alizadeh et al., 2004; area) are faced with the dual problems of Moghaddam and Koocheki, 2004). The soil salinization and water logging salinization of land and water resources (Anonymous, 2000). has been the consequence of both Karkheh River Basin (KRB) is one of the anthropogenic activities (causing human- major river basins in the Khuzestan induced or secondary salinity and/or sodic- province consisting of two main sub-basins ity) and naturally occurring phenomena namely Karkheh Olia (upstream) and (causing primary fossil salinity and/or sodici- Karkheh Sofla (downstream). The Karkheh ty) (Ghassemi et al., 1995). The main crop- River Basin is, most notably, the eastern ping systems in the country are based on flank of the 'cradle of civilization' (ancient irrigated agriculture where at least 50% Mesopotamia) and a boundary between area (4.1 Mha) falls under different types of the Arab and Persian cultures. This major salt-affected soils (Cheraghi, 2004). river system of western Iran has unique Therefore, the dependency on irrigated agricultural and hydrological aspects; but agriculture is at stake in areas where salt- also much in common with other catch- prone land and water resources degrada- ments around the world, e.g., rural poverty tion has increased over time. and land degradation, low water and agri- cultural productivity, a dry climate, and Human-induced salinization of land and growing upstream-downstream competi- water resources has occurred mostly in tion for water. Agriculture in the upstream unique topographic conditions of semi- basin is mainly rain fed, while the down- closed or closed intermountain basins stream basin is mostly irrigated. The where irrigated agriculture has been prac- drainage outlet of the KRB, which also is a ticed for centuries. The slightly and moder- basin outlet, is the Hoor-Al-Azim swamp in ately salt-affected soils are mostly formed southwest Iran and on the Iran-Iraq border on the piedmonts at the foot of the Elburz (Figure 12). At present, there are very limit- (Alborz) Mountains in the northern part of ed modern irrigation and drainage net- the country. The soils with severe to works under operation within the KRB and extreme salinity are mostly located in the agriculture is yet to be fully developed. Central Plateau, the Khuzestan and However, the government has started con- Southern Coastal Plains, and the Caspian structing irrigation and drainage networks Coastal Plain (Koocheki and Moghaddam, with the goal of improving the traditional 2004). ). The extent and characteristics of irrigation systems, e.g., in the Dasht-e- salt-affected soils in Iran has been investi- Azadegan (DA) plain in southern parts of gated by several researchers (Dewan and the Lower KRB (LKRB). Famouri, 1964; Mahjoory, 1979; Abtahi et al., 1979; Matsumoto and Cho, 1985; Banie, In southern parts of the Lower KRB (LKRB), 2001). available data and surveys show that the problem of soil salinity is magnified by lack Owing to abundant water resources, fertile of availability of new and improved farm- lands and sufficient extraterrestrial energy, ing practices and farmers' knowledge Khuzestan province in the southwest Iran is about salinity and shallow water table one of the potentially most suitable regions management under irrigation. In general,

83 Fig. 12. Lower part of Karkheh river basin in Khuzestan province. the main cause of soil salinity in the LKRB is people, of which 65% are living in the high water-table, often less than 2 m; usu- towns. The total number of villages at pres- ally 1.2-3.0 m below the soil surface, ent is 180, a number that was nearly twice (Anonymous, 1989). If left without appropri- before many were displaced in early 1980s ate management, the problem is likely to by the Iraq-Iran conflict (Anonymous, worsen considering the current plans for 1989). expansion of irrigation networks. The source of irrigation water is mostly by Dasht-e-Azadegan consists of three subdi- pumping from the Karkheh River into con- visions (or towns), namely Sosangerd, veyance irrigation canals. There are also Hoveyzeh, and Bostan. The total area of limited constructed irrigation networks in DA is 334,000 ha, of which only 70,000 ha the region. The main canals and drains are (20%) is currently cultivated due to short- mostly completed or under construction, age of available water resources and con- but there are no secondary or tertiary irri- veyance networks. Upon completion of the gation canals or drain laterals. At present, planned irrigation networks, an additional despite the construction and operation of area of about 60,000 ha will be added to main drains in the area, the system is not the irrigation area. Only in the southern properly functioning at all areas. This is part of Hoveyzeh (see Fig. 12), there are mainly due to technical and excavation 60,000 ha of non-cultivated arable land. problems (i.e., improper slope of drainage Total population of DA is almost 160,000 lines) and due to problems concerning the

84 outlet. Gravitational drainage to outlet is cause of salinity in the area. Seepage from practically not feasible and pumping is irrigation channels most of which are required. Negative environmental impacts unlined and deep percolation losses from regarding drainage flow directly into the conventional surface irrigation methods Hoor-Al-Azim swamp is also another con- largely contribute to groundwater rise and cern that should be considered. salinization of soil.

The soils of the area are alluvial formed This paper presents major causes of soil originally by the floods of the river. The allu- salinity along with a review of some of the vial areas are flat and soil permeability is research work carried out in the lower KRB low with a little slope and poor natural with respect to soil salinity. The article con- drainage. The groundwater level is close to cludes by drawing attention to areas the surface and a slow salt accumulation where research is needed. has occurred. Salinization has occurred pri- marily in the top soil layers and is dominat- ed by chloride salinity, as evidenced by MAJOR CAUSES OF SOIL SALINITY IN the high correlation between chloride ion THE LOWER KARKHEH BASIN concentration and electrical conductivity shown in Figure 13. River banks and elevat- Major factors causing soil salinization in the ed areas are slightly saline to non-saline, lower Karkheh Basin can be classified as whereas strong salt accumulation is follows (Balali, et al., 2000; Ghobadian, observed in depressions remote from the 1969): river where salt is build up by water seep- 1. High groundwater table ing from the river. An estimate of the total 2. Salt containing layers salt-affected soils exceeds 225,000 ha, out 3. Inadequate drainage facilities of which only 92,000 ha is suitable for irriga- 4. High evaporation tion (Anonymous, 2000). 5. Salt intrusion by wind 6. Sediment transport during flood peri- Besides the above-mentioned factors, sec- ods ondary salinization is also an important

Fig. 13. Correlation between electrical conductivity (dS m-1) and Cl- concentration (meq L-1) for water and soil solution samples in DA.

85 High Groundwater Table popular signs of this kind is mottling (segre- gation of subdominant color different from High water tables is the major factor of soil surrounding region's color). In Ahmadabad salinization in Khuzestan province. The salt soil series (west of Dasht-e-Azadegan), concentration in groundwater is extremely which is heavy textured and has a hard high, exceeding 100 g L-1 in many cases. It massive structure, gley spots are observed should be mentioned that groundwater in some profiles below 1 m depth. could cause salinity in cases where its level is higher than a certain depth. This specific In Abohomayzeh soil series, weak gley depth of groundwater is called critical spots and mottling can be observed. West depth, which varies between 2.5-3.5 m. It of the Bostan- Pol-e-Ramazam road and means that soil salinization due to capillar- near Shatt-e-Abbas, Machriyeh, Jarrahieh, ies and its accumulation in the plow layer and Lulieh soil series, which are generally will be expected if the distance between flooded during early winter up to late the soil surface and the water table is spring, the soil, is usually waterlogged half smaller than the above-mentioned depth. of the year. Therefore, the soil moisture regime at the moisture control section of In arid and semi-arid regions such as these profiles is aquic with diagnostic Khuzestan province where upward water symptoms of mottling and gley spots. flux due to high evaporation is consider- able, even fresh groundwater causes soil Salt Containing Layers salinization because of high groundwater level. Investigations have shown that in A salt containing layer is a horizon or a most parts of Khuzestan, groundwater level layer of geological material in which salt is higher than the critical depth. This case is content is not only high, but also higher especially true for the regions where than the rest of the soil profile. If these lay- extended agriculture had developed. It is ers are located in a depth less than 0.5 m observed that in non-arable lands, the below the soil surface, especially in heavy groundwater level is usually deeper than textured soils, top soil salinization occurs as the critical depth, but near villages where in the case of Khuzestan. agricultural practices are more intensified, the problem is more severe. In LKRB, the In DA plain, despite high calcium carbon- groundwater level in non-arable land (or ate and calcium sulfate content of the soil, specific locations which had not been cul- no calcic or gypsic diagnostic horizons tivated during the Iran-Iraq war 1979-1989) were identified. However, accumulation of varies between 4-7 m while its level is hygroscopic salts such as CaCl2, MgCl2, about 1.2-3.0 m in cultivated land. This dif- MgSO4, and KCl in combination with NaCl ference shows the significance of agricul- can be observed in both sides of river tural return flow effects. banks. High temperature differences between river, lateral canals and irrigated A high groundwater level for extended land causes moisture diffusion and evapo- periods, especially in the hot season, caus- ration that in turn leaves huge amounts of es specific morphological characteristics in salt on the soil surface. Salic diagnostic the soil profile, which are the results of peri- horizons had been identified only in odic oxidation- reduction conditions due Abohomayzeh, Kout and Jarahyeh soil to variations of the ground water level. series. In Abohomayzeh and Jarahyeh These specific symptoms are more pro- series, soil surface is highly dispersed. nounced in the presence of organic car- bon and sesquioxides. One of the most

86 Inadequate Drainage Facilities High Evaporation

Most of Khuzestan's soils are heavy textured One of the factors which accelerate soil and have a slight slope and therefore, the salinization under high ground water condi- importance of adequate drainage facili- tion is high evaporative demand, which ties is obvious. However, in many cases lit- causes continuous upward flux of salt con- tle attention has been paid to this prob- taining water to the top soil or at least in lem. Drains, which had been dug, are gen- the warm season. Critical depth of ground- erally the main drains and are deep. water table which will cause soil salinization Although these drains can partly absorb is highly dependent on evaporation rate the drainage water of the surrounding beside the soil type. For example in area, their effective radius is small. Natural Khuzestan it had been reported to be vari- drains, which discharge to the main outlet able between 2.5 and 3.5 m based on soil of the region (Hoor-Al-Azim), are not func- type and evaporation demand. tioning well due to technical and environ- Occurrance of 260 dry days in Hamidieh, mental problems and due to the very low and 290 dry days in Ahvaz, are some cli- slope of land. Problems associated with matic characters of the region. In inadequate drainage are more serious in Hamidieh, annual precipitation is 245 mm low lands and areas with low slope. while annual evaporation is 2205 mm, or evaporation to precipitation ratio exceed- The West side of DA is usually flooded dur- ing nine. Surface evaporation is one of the ing winter and spring. During summer, salts, most important meteorological factors in which have been leached into the sub-soil, the region affecting soil genesis processes tend to rise and accumulate on the soil significantly. High evaporation leads to surface due to the high evaporation. The capillary rise of soluble salts and their accu- surface of these soils is often cracked dur- mulation at the soil surface. Table 20 pres- ing the hot and dry season, which is relat- ents some climatic characters of Khuzestan ed to the high clay content of these soils. province. As a result, infiltration rates are low.

Table 20: Long-term meteorological data of selected stations in Khuzestan province. station mean Mean air absolute total mean annual temperature (°C) temperature precipitation relative evaporation (°C) (mm) humidity (mm) Max. Min. Mean Min. Max. (%) Abadan 4077 32.7 17.7 25.2 -5 53 155 46 Omidie 3514 33.0 17.2 25.1 -2 51 260 48 Ahvaz 3517 32.8 17.2 25.0 -7 54 233 43 2667 27.8 13.9 23 -6.8 46 637 41 Bostan 3619 31.7S 15.3 23.5 -4 50.8 217 47 Behbahan 3446 32.2 16.8 25.1 -2.8 50.6 332 42 Ramhormoz 2981 32 18.6 25.3 -0.6 50.2 301 40 Dezfoul 2334 31.4 15.3 23.4 -1.8 50.5 370 46 Shooshtar 3665 32.8 20.1 27.6 -0.2 51.8 317 39 Mahshahr 3944 32 17.9 24.9 -2 51 220 45 3246 31 18.9 25 -4.4 51 450 38

87 Salt Intrusion by Wind the low lands. Typical examples are the small swamps around the Hour-Al- The dominant directions of winds in this Hoveyzeh. In 1968, about 3000-4000 km2 of region are west, northwest, and southeast, Khuzestan province were flooded with esti- which occur as dust storms. They carry mated sediment loads of about 1.5 million huge quantities of sediments that are most- tonnes of salt on the soil surface ly deposited on the surface of the plains. It (Ghobadian, 1969) had been estimated that in each storm -1 event about 5-50 kg salts ha is deposited PAST RESEARCH AND DEVELOPMENT on the soil surface, which accumulates to about 200-1000 kg ha-1 annually. It is sug- Soil desalinization and land reclamation gested that the deposited salts originate research in Khuzestan province has a rela- from the coastal lands of both sides of the tively long history when compared to other Persian Gulf and of the Gulf of Oman. They provinces. Mohajer Milani and Javaheri are salt intrusion by wind erosion. These salt (1998) summarized the result of a series of deposits are translocated within the region. experiments conducted by the Soil and It has been estimated for Khuzestan Water Research Institute (SWRI) on leach- province that 10-50 mg salts ha-1 are ing behavior of soils throughout the coun- translocated from one point to another. It try. In a general conclusion, they pointed should be mentioned that the risk of accu- out that for leaching 80% of salts of a soil mulation of these salts is more serious layer, approximately the same depth of around the villages (Ghobadian, 1969). water is required (Fig. 14).

Sediment Transport in the Flood Periods The origin of most of the soil series in DA derives from the sediments of Karkheh River and its branches except for the low lands. Hence, the salt content of sediments from Karkheh River affects salinity and sodicity of these soils. In the low lands, there is no horizontal stratification of the soils, although this fact may be related to pedoturbation in heavy textured soils as the case of Shat- e-Abbas soil series. Except for Jarahyeh series, which is highly saline and sodic, the other soil series of this region are naturally leached by Karkheh River and its branches.

The groundwater level in these areas is Fig. 14. Soil desalinization curve for south highly variable and is affected by the dif- Khuzestan 1986. (After Mohajer Milani and ferent seasons. During winter and spring, Javaheri, 1998). soils are completely waterlogged. In con- trast, during early summer the groundwater DW is the depth of the leaching water (m), DX table is relatively high while it is low in fall. is the soil depth (m), ECi is the initial salinity of soil saturation extract before leaching (dS/m), After flood periods, large parts of the ECf is the final salinity of soil saturation extract region are submerged. During the dry sea- after leaching (dS/m) and ECeq represents the son, water drawing back from land of high- salinity of soil saturation extract obtained after er elevation leads to the formation of small salinity has reached an equilibrium under speci- swamps (Hour) and permanent ponds in fied local conditions.

88 In another study by Pazira and ried out by SWRI (1972) indicated that Sadeghzadeh (1998), the desalinization leaching in combination with rice and curve and equation for some soil series of clover cultivation improved the physico- Khuzestan was determined (Fig. 15). chemical properties of salt-affected soils.

For the studied soils, the following equation Saremi (2000) evaluated the effect of phy- was developed: toremediation of saline-sodic soils using for- ages like Kallar grass (Leptochloa fusca L. Kunth). The results showed that the grass (ECi - ECeq) / (ECf - ECeq) = 0.0761(DS/ Dlw) cultivation had reduced soil salinity in 0-0.3 + 0.023...... (1) m depth layer by 70% and sodium adsorp- where Dlw is the depth of the leaching tion ratio (SAR) by 60% while producing water (m), DS is the soil depth (m), ECi is about 22 tonnes fresh forage ha-1. the initial salinity of soil saturation extract before leaching (dS/m), ECf is the final The effect of different irrigation methods salinity of soil saturation extract after leach- under saline conditions on wheat yield was ing (dS/m) and ECeq represents the salinity studied in Khuzestan province (Soleiman of soil saturation extract obtained after Nejad, 1998). Results of his trails in DA salinity has reached an equilibrium under showed that border irrigation gave maxi- specified local conditions. mum yield in comparison to furrow and tra- ditional systems. The difference in yield Pazira (1974) studied the effect of drains between border and furrow irrigation was spacing on soil chemical properties and 292.5 K ha-1, which was statistically signifi- wheat yield. It was found that a horizontal cant at 0.01 levels. This difference was distance of the drains of 150 m improved 172.5 K ha-1 when compared to traditional soil chemical properties, but its effect was system and was not significant. On the not significant on grain yield. A study car- other hand, it was mentioned that soil sur-

Fig. 15. Soil desalinization leaching curve for some saline soils in Iran. (After Pazira et al., 1998).

89 face salinity in late summer is 2-5 times drainage system is incomplete. Lateral higher than its salinity in early spring due to connections are lacking, and the drainage upward transport of salts after harvest. system covers only a limited area under irri- Therefore, soil leaching before sowing is a gation. It is noted that agricultural man- pre-requisite. agement practices cannot serve as a sub- stitute for adequate drainage of salt Little information is available on the effect affected and waterlogged soils. Most of different soil conditioners on ameliorat- efforts in improved management to ing soils' physico-chemical properties. It reduce the impact of salinity are suggest- seems that most efforts have been con- ed to have a rather temporary effect. To centrated on the effect of different fertilizer avoid further salinization of agricultural soils, sources and amounts on crop production the communities and agricultural agencies under saline conditions of this province. are called to apply sound management Balali et al. (2000) presented a computer practices until an adequate drainage is model for fertilizer recommendation of installed. wheat. In this model, the production potential of wheat for different provinces The agricultural cropping systems and of the country is determined and fertilizer practices in the subject area are subopti- recommendation is presented based on mal and should be improved. Appropriate this value. However, under saline condi- irrigation schedules based on soil moisture tions the recommendation is adjusted due depletion or climatic data would prevent to the type of fertilizer and level of salinity. excess losses of irrigation water into the subsoil or groundwater. To increase the effi- So far, no salt-tolerant crop variety suitable ciency of water use, irrigation water must for saline conditions of the province has be applied uniformly. Land levelling could been released. Two wheat cultivars culti- improve water distribution and limit water- vated in saline areas, namely Chamran logging problems. At present, the crop and Verinak, were originally released for varieties used by farmers are not adapted dry land and warm climates in Khuzestan to the prevailing soil conditions and signifi- province (SPII, 1990), and were not neces- cant improvements in production could be sarily salt-tolerant varieties. Their pedigree is realized by introducing salt-tolerant vari- Vee kf/ Nac kf and Attilla 50, respectively. eties. Another wheat variety that is common in this region is Yavarous, which is durum Another important factor limiting crop pro- wheat. duction is the accumulation of salt in the top soil, which mainly occurs during the fal- FUTURE RESEARCH AND low period when the soil is uncultivated. DEVELOPMENT Leaching of salts before sowing can reduce the adverse effects of salt on crop Existence of drainage is fundamental to establishment. Other suitable practices are improving the quality of salt-affected soils. trash mulching and suitable crop rotations. It reduces the adverse effects of shallow There are also knowledge gaps on the water tables and water logging, and effect of chemical amendments on ame- hence, improves crop production. There is liorating physical-chemical properties of no doubt that one of most important sodic soils. needs for the study area is to complete an adequate drainage network for the entire One of the most important pre-requisites to irrigated area. Encouraging efforts has enable permanent crop production in this been initiated in this regard, but the region is the development of a monitoring

90 network comprising monitoring the effect agriculture in Iran. in F.K. Taha, , S. Ismail and of different management practices on the A. Jaradat, eds., Prospects of Saline salt content of groundwater as well as salt Agriculture in the Arabian Peninsula: and water balance of the root zone. These Proceedings of the International Seminar on Prospects of Saline Agriculture in the GCC regular measurements will provide the Countries, 18-20 March 2001, Dubai, United data required to suggest the best methods Arab Emirates, pp. 399-412. to prevent salinity in the root zone and Dewan M.L, and J. Famouri. 1964. The soils of groundwater. On the other hand, water Iran. Food and Agriculture Organization of and salt balance studies at the watershed the United Nations, Rome. scale will increase our ability to predict the Ghassemi, E., A. J. Jakeman, and H. A., Nix. role of any hydrological unit in the fate 1995. Salinization of land and water and behavior of catchments. resources, CABI. Wallingford Oxon. Ghobadian, A., 1969. Causes leading to soil salinity in Khuzestan & their control, College REFERENCES of Agriculture, Jundi Shapur University, Publication number 1, Ahvaz, Iran. Abtahi A, Sys C, Stoops G, Eswaran H. 1979. Soil Hajrasuliha, S. 1970. Irrigation and drainage forming processes under the influence of practices in Haft-Tappeh cane sugar proj- saline and alkaline groundwater in the ect, In 8th Near East, South Asia Regional Sarvestan Basin (Iran). Pédologie 29: 325-357. Irrigation Practices Seminar, Kabul, Alizadeh, A., I. Malak-Mohammadi, G.A. Kamali, Afghanistan. Sponsored by the United States 2004. Sustainable utilization of saline water in Agency for International Development. Utah agriculture based on indigenous knowledge. State University Printing Service, Utah, USA, in F.K. Taha, , S. Ismail and A. Jaradat, eds., 117-143. Prospects of Saline Agriculture in the Arabian Koocheki A, Moghaddam PR. 2004. History of Peninsula: Proceedings of the International research on salt-affected lands of Iran: pres- Seminar on Prospects of Saline Agriculture in ent status and future prospects. in F.K. Taha, the GCC Countries, 18-20 March 2001, , S. Ismail and A. Jaradat, eds., Prospects of Dubai, United Arab Emirates, pp. 483-490. Saline Agriculture in the Arabian Peninsula: Anonymous, 1972, Evaluation the effect of a Proceedings of the International Seminar on period of reclamation rotation on variation Prospects of Saline Agriculture in the GCC of soil qualities and grain yield. Soil and Countries, 18-20 March 2001, Dubai, United water research institute of Iran, Ministry of Arab Emirates, pp. 507-520. agriculture, Tehran, Iran. 100 p.(In Persian) Mahjoory RA. 1979. The nature and genesis of Anonymous, 1989, Soil survey of West Dasht-e- salt-affected soils in Iran. Soil Science Society Azadegan, Ministry of Energy. Tehran, Iran. of America Journal 43: 1019-1024. 186 p. (In Persian) Matsumoto, S. and Cho, T. 1985. Field investiga- Anonymous, 2000, Evaluation of methods and tion on the agricultural development of arid amount of the salinization in capable lands regions in Iran, III soil profile investigations of Khuzestan province. Management and and salt accumulation related to the depth Planning Organization of Khuzestan of ground water level, J. of the faculty of Province, Ahvaz, Iran. 752 p. (in Persian) agriculture, Tottori University (Japan) 20: 86- Balali, M. R., P. Mohajer Milani, Z. Khademi, M. S. 97. Dorodi, H. H. Mashayekhi and M. J. Moghaddam PR, Koocheki A. 2004. History of Malakouti, 2000. A comprehensive computer research on salt-affected lands of Iran: pres- model for fertilizer recommendation towards ent status and future prospects - halophytic sustainable agriculture. Wheat. Nashr-e- ecosystems. in F.K. Taha, , S. Ismail and A. Amouzesh-e-Keshavarzi. 64 p. (In Persian) Jaradat, eds., Prospects of Saline Agriculture Banie M H. 2001. Soils Map of IRAN: Land in the Arabian Peninsula: Proceedings of the Resources and Potentialities, Soil and Water International Seminar on Prospects of Saline Research Institute (SWRI), Tehran. Agriculture in the GCC Countries, 18-20 Cheraghi SAM. 2004. Institutional and scientific March 2001, Dubai, United Arab Emirates, profiles of organizations working on saline pp. 83-95. Mohajer Milani, P., and P. Javaheri, 1998.

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92 Project National Team in Iran Engr. A. Anagholi - National Salinity Research Center, Yazd Dr Z. Shoaei - Director General, Dept of Intl Engr. A. Abayani - Khuzestan Agricultural & Scientific & Research Affairs, AREO, and Focal Natural Resources Research Center, Ahwaz Person for CPWF projects in Karkheh River Engr. A.R. Tavakoli - Irrigation Researcher, DARI, Basin (KRB), Tehran Kermanshah Dr A. Javadi - Director, Agricultural Engg Engr. H. Asadi - Research staff, Seed & Plant Research Institute (AERI), and National Improvement Research Institute, Agricultural About ICARDA and the CGIAR Coordinator of Water Productivity Project, Economics, Karaj Karaj Engr. A. Ayeneh - Seed & Plant Improvement Res. Dr M.H. Davoudi - Director, Soil Conservation & Div., Khuzestan Ag. Research Center, Ahwaz Established in 1977, the International Center for Agricultural Research Watershed Mgmt Research Institute, Tehran in the Dry Areas (ICARDA) is one of 15 centers supported by the Engr. F. Mazraeh - Extension Div. of Azadegan Dr S.A.M. Cheraghi - Director, National Salinity and Sorkheh Agricultural Mgmt Dept, CGIAR. ICARDA’s mission is to improve the welfare of poor people Research Center, and Principal Investigator of Khuzestan Agricultural Organization, Ahwaz through research and training in dry areas of the developing world, Water Productivity Project, Yazd Engr. M. Ghamarinejad - Head of Agricultural by increasing the production, productivity and nutritional quality of Dr A. Ghaffari - Director, Dryland Agricultural Service Center of Sorkheh Agricultural Mgmt food, while preserving and enhancing the natural resource base. Research Institute, Maragheh Dept, Khuzestan Jihad-e-Agricultural ICARDA serves the entire developing world for the improvement of lentil, Dr F. Abbasi - Deputy Director Assistant Organization, Dezful barley and faba bean; all dry-area developing countries for the improvement of Coordinator of Water Productivity Project, on-farm water-use efficiency, rangeland and small-ruminant production; and the AERI, Karaj Project International Team Central and West Asia and North Africa (CWANA) region for the improvement of Dr N. Heydari - CPWF Karkheh Basin Coordinator, bread and durum wheats, chickpea, pasture and forage legumes, and farming Irrigation & Drainage Dept, AERI, Karaj Dr. T.Oweis - Director, Integrated Water & Land systems. ICARDA’s research provides global benefits of poverty alleviation Dr H. Dehghanisanij - Irrigation & Drainage Dept, Management Program, & Project Manager of through productivity improvements integrated with sustainable natural-resource AERI, Karaj Water Productivity, International Center for management practices. ICARDA meets this challenge through research, train- Dr M. Akbari - Irrigation & Drainage Dept, AERI, Agricultural Research in the Dry Areas - ICAR- ing, and dissemination of information in partnership with the national, regional Karaj DA, Aleppo, Syria and international agricultural research and development systems. Dr S. Ashrafi - Irrigation & Drainage Dept, AERI, Dr. H. Farahani - Integrated Water & Land Karaj Management Program, & Assist. Project Engr. A. Keshavarz - Senior Irrigation & Water Manager of Water Productivity, ICARDA, The Consultative Group on International Agricultural Research Mgmt Scientist, Principal Investigator and for- Aleppo (CGIAR) is a strategic alliance of countries, international and regional mer National Coordinator of Water Dr. H. Siadat - Integrated Water & Land organizations, and private foundations supporting 15 international Productivity Project, Tehran Management Program, & agricultural Centers that work with national agricultural research sys- Dr S.A. Asadollahi - Director General and Under Facilitator/Coordinator of Water Productivity, tems and civil society organizations including the private sector. The Secretary of Iranian National Committee on ICARDA, Tehran alliance mobilizes agricultural science to reduce poverty, foster Irrigation & Drainage, Ministry of Energy, Dr. A. Bruggeman - Integrated Water & Land human well being, promote agricultural growth and protect the environment. Tehran Management Program, ICARDA, Aleppo The CGIAR generates global public goods that are available to all. Dr E. Pazira - Professor, Azad Islamic University, Dr. M. Qadir- Integrated Water & Land The World Bank, the Food and Agriculture Organization of the United Nations Research Science Division, Tehran Management Program, ICARDA, Aleppo (FAO), the United Nations Development Programme (UNDP), and the Engr. M. Moayeri - Director, Safi Abad Research Dr. K. Shideed - Director, Social, Economic & International Fund for Agricultural Development (IFAD) are cosponsors of the Station, Dezful Policy Rsrch.Prog., & PI of Water Productivity CGIAR. The World Bank provides the CGIAR with a System Office in Washington, Engr. B. Hessari - Irrigation Researcher, AERI project, ICARDA, Aleppo DC. A Science Council, with its Secretariat at FAO in Rome, assists the System in branch in West Azarbaijan Ag. Research Dr. E. De Pauw - Head, Geographic Info. Systs. the development of its research program. Center, Uromieh Unit, & PI of Water Productivity project, ICAR- Engr. S. Absalan - Agricultural Engg Research Div, DA, Aleppo Khuzestan Ag. Research Center, Ahwaz Dr. J. Anthofer - Integrated Water & Land Engr. E. Dehghan - Agricultural Engg Research Management Program, ICARDA, Aleppo Div, Khuzestan Ag. Research Center, Ahwaz Dr. M. Pala - Integrated Water & Land Engr. A.F. Nato - Research Staff, Safi Abad Ag. Management Program, ICARDA, Aleppo Research Center, Dezful Dr. T. Hsiao - Prof., University of California at Davis, Engr. Y. Hasheminejhad - National Salinity & PI of Water Productivity project, Davis, Research Center, Yazd California, USA Engr. G.H. Ranjbar - National Salinity Research Dr. A. Qureshi - International Water Management Center, Yazd Institute, & PI of Water Productivity project, Engr. M.H. Rahimian - National Salinity Research Karaj Center, Yazd ICARDA-01/500/Salhani/January 2008