Improving on-farm agricultural water productivity in the Karkheh River Basin

Improving On-farm Agricultural Water Productivity in the Karkheh River Basin (KRB) was a CPWF project that aimed at enhancement of agricultural water productivity (WP) under irrigated and rainfed conditions in Karkheh River Basin. It was launched in Iran through the partnership of ICARDA and the Iranian NARES under the Agricultural Extension, Education, and Research Organization. The project lasted for more than four years between 2004 and 2008. Whereas capacity building was an important part of the agenda, PN8 was a participatory, multi-disciplinary, and action-oriented project that carried out mostly on-farm trials. Findings included existing crop water productivity, suitable technologies for their improvement, interactions between the upper and lower KRB, and a review of the prevailing water policies and institution

Management alternatives for improved durum wheat production under supplemental irrigation

Abstract In the Mediterranean zone, efforts to optimize combinations of supplemental irrigation (SI ), improved varieties, nitrogen (N ) and sowing dates aim to improve and stabilize cereal yields and maintain quality, especially for durum wheat. Thus, a 4 year field study (1992/1993 to 1995/1996) on a deep clay soil in northern Syria assessed the impact of SI (rain-fed, 1/3, 2/3 and full SI ) combined with variable N application rates (0, 50, 100, 150 kg ha−1) and sowing date (early, normal, late) for four improved durum wheat varieties adapted to rain-fed and irrigated conditions. As rainfall and evapotranspiration varied over the 4 years, the amount of SI water required also varied. Yields varied with the season, and the main factors, except variety, were significant. Delaying sowing from November to January reduced yields and response to both SI and N. With irrigation, crop responses were generally significant up to 100 N ha−1, whereas the optimum response for rain-fed conditions occurred with 50 kg N ha−1. Limited SI (1/3) significantly increased yields, but almost maximum yields were obtained by 2/3 of full SI. Water-and N-use efficiencies were greatly increased by SI, with little variation among varieties. However, irrigation and delayed sowing decreased grain protein levels, which were partially compensated for by added N. A similar effect was observed for kernel vitreousness. Models developed from the response data can facilitate the potential transfer of these findings. Thus, in most growing seasons, minimum irrigation during the winter growing season, combined with appropriate fertilization, can enhance wheat output and yet maintain grain quality

Water for all : making SDG 6 a reality

"Water for all" is an important concept embedded in Sustainable Development Goal 6 on Water and Sanitation. However, implementation does not currently target differential access for women and marginalised people. Our authors show what actions are needed to resolve growing tensions around water scarcity and degradation, thus meeting the needs of the poor and vulnerable

Supplemental irrigation: A promising climate-smart practice for dryland agriculture

Supplemental irrigation - the addition of limited amounts of water to essentially rainfed crops to improve and stabilize yields when rainfall fails to provide sufficient moisture for normal plant growth - is an effective response to alleviating the adverse effects of soil moisture stress on the yield of rainfed crops during dry spells. Supplemental irrigation, especially during critical crop growth stages, can improve crop yield and water productivity

Rainwater harvesting for restoring degraded dry agro-pastoral ecosystems; a conceptual review of opportunities and constraints in a changing climate

Water resources in dry environments are becoming scarcer, especially under the changing climate. In response, rainwater harvesting (RWH) is being reemphasized with calls to revive the practice. Ancient knowledge on RWH â mainly the collection through runoff, storage, and use of rainwater for various purposes â is still relevant, especially for dry environments. However, many old practices and technologies may not be suitable or feasible for the present and future. Little has been done to modernize and/or develop new practices and technologies based on ancient indigenous knowledge. Modernizing old practices or developing new ones and using them in integrated rangelands restoration packages with enabling policy environment can unlock their potential in many water-scarce regions of the world. This paper reviews the state-of-the-art of micro-catchment rainwater harvesting (MIRWH) in dry environments and discusses the opportunities available and the major obstacles faced in using it to restore degraded agro-pastoral ecosystems and support their sustainability. The review highlights the knowledge behind it, the practices developed over the years and their relevance to today and the future. The paper indicates areas of modernization that can make it more feasible for the future of the dry environments, especially their role in mitigating and adapting to climate change. Conventional and passive approaches to restoring/rehabilitating degraded dry agro-pastoral ecosystems are either too slow to show an obvious impact or not progressing satisfactorily. One main reason is that, because of land degradation, the majority of rain falling on such ecosystems and needed for revegetation is lost with little benefit being gained. Adopting a more progressive intervention to alter the processes of degradation and move towards new system equilibrium is required. MIRWH can enable a large portion of this otherwise lost rainwater to be stored in the soil and, if used in an integrated packages including suitable plant species and sound grazing management, it may support meaningful vegetation growth and help system restoration. The Badia Benchmark project, implemented by ICARDA in Jordan and Syria, has demonstrated the potential for adoption at large scale in similar environments. This case study illustrates the potential and the constraints of this practice.The accepted manuscript in pdf format is listed with the files at the bottom of this page. The presentation of the authors' names and (or) special characters in the title of the manuscript may differ slightly between what is listed on this page and what is listed in the pdf file of the accepted manuscript; that in the pdf file of the accepted manuscript is what was submitted by the author

Optimizing supplemental irrigation: Tradeoffs between profitability and sustainability

Water production functions are used to model yield response to various levels of supplemental irrigation (SI), to assess water productivity coefficients, and to identify optimum irrigation under various input-output price scenarios. The SI production function is taken as the difference between the total water production function (irrigation + rain) and that of rainwater. Theoretical analysis of the unconstrained objective function shows that the seasonal depth of SI to maximize profit occurs when the marginal product of water equals the ratio of unit water cost to unit product sale price. Applying this analysis to wheat in northern Syria, the production functions of SI under different rainfall conditions are developed. Coupled with current and projected water costs and wheat sale prices, the functions are used to develop an easy-to-use chart for determining seasonal irrigation rates to maximize profit under a range of seasonal rainfall amounts. Results show that, for a given seasonal rainfall, there is a critical value for the ratio of irrigation cost to production price beyond which SI becomes less profitable than rainfed production. Higher product prices and lower irrigation costs encourage the use of more water. Policies supporting high wheat prices and low irrigation costs encourage maximizing yields but with low water productivity. The resulting farmer practice threatens the sustainability of water resources. Balancing profitability versus sustainability is a challenge for policy makers. Our analysis can help national and local water authorities and policy makers determine appropriate policies for water valuation and allocation; and assist extension services and farmers in planning irrigation infrastructure and farm water management.Water productivity Water use efficiency Syria Water valuation Rainfed agriculture Durum wheat