First title in a major new seriesAddresses improving water productivity to relieve problems of scarcity and competition to provide for food and environmental securityDraws from scientists having a multitude of disciplines to approach this important problemIn a large number of developing countries, policy makers and researchers are increasingly aware of the conflicting demands on water, and look at agriculture to be more effective in its use of water. Focusing on both irrigated and rain-fed agriculture, this book gives a state of the art review of the limits and opportunities for improving water productivity in crop production. It demonstrates how efficiency of water use can be enhanced to maximize yields. The book represents the first in a new series of volumes resulting from the Comprehensive Assessment of Water Management in Agriculture, a research program conducted by the CGIAR's Future Harvest Centres, the Food and Agriculture Organization of the United Nations and partners worldwide. It will be of significant interest to those working in areas of soil and crop science, water management, irrigation, and development studies.

Agriculture is certainly the most important food supplier while it globally accounts for more than 70% of water used and contributes significantly to water pollution. Irrigated agriculture is facing rising competition worldwide for access to reliable, low cost, and high-quality water resources. However, irrigation as the major tool and determinant of affecting agricultural productivity and environmental resources plays a critical role in food security and environment sustainability. Innovative irrigation technologies and practices may enhance agricultural water efficiency and production, in the meantime decrease the water demand and quality issues. I am very pleased to invite you to submit manuscripts in agricultural irrigation which assess current challenges and offer improvement approaches and opportunities for future irrigation.

Water scarcity has become one of the greatest challenges facing humankind today. Its scarcity is compounded by climate change and increasing demand from a growing population. In South Africa, over 60% of the available freshwater resources are used in agriculture, mainly in irrigated agriculture. There is an urgent need to promote sustainable irrigation technologies that optimize food production without increasing water applied and with positive environmental spinoffs. Sustainable irrigation technologies and practices could enhance water use efficiency (WUE) and productivity in agriculture and reduce environmental burdens, including energy use. This chapter highlights some of the innovative irrigation practices and technologies that enhance food production and, at the same time, reduce water use in agriculture. The chapter broadly discusses WUE and water productivity (WP) in irrigated agriculture from engineering and agronomic perspectives. The chapter further highlights some of the environmental impacts of irrigation expansion and the possible solutions. We further provide the importance of accurate spatial information on irrigated areas to inform policy on irrigation expansion. The Water Research Commission (WRC) of South Africa has been spearheading research on the sustainable use of water for the past 50 years as part of its research agenda. In Ting, D. S.-K.; O’Brien, P. G. (Eds.). Progress in sustainable development: sustainable engineering practices. Amsterdam, Netherlands: Elsevier

In developing countries, further progress of irrigation is essential for increasing food security and farmers’ income. However, developing small-scale schemes remains a challenge due to multiple factors that must be taken into consideration, such as diversity of small-scale schemes, a large number of water users, social disharmony over the water use, varying water demands of multi-cropping systems, heterogeneity of equipment over the scheme. Furthermore, on-farm irrigation development has a major role in enhancing Agricultural Water Management (AWM). The previous development methods considered the improvement of single-factor productivity, but agriculture is undergoing a global shift from the single objective of outputs (such as yield or net income) to multiple objectives of increasing outputs while conserving natural resources. Many pathways towards enhancement of Water Productivity (WP) are directly related to improving overall farm agronomic management (irrigation, fertilization, plant density, plant protection, etc.), while external measures must be applied to ensure sustainability of introduced good practices (lack of input markets, scarce knowledge, poor infrastructures, water regulations, etc.). Thus introducing irrigation practices to farmers must undergo a step-wise process to ensure that costs do not outweigh achievable benefits, and both institutional and technical environment are capable to sustain results. This is the case in smallholders’ schemes, where farmers are poorly resourced. In order to address these issues, the current policy guide presents a combined methodology, which involves practical experiences drawn from FAO work in the three countries as well as researchers’ results to line up a set of feasible measures to improving WP.

Traditionally, indigenous irrigation in many countries of Asia, Africa, and Latin America has been managed quite well by water users, who design, build, operate, and maintain often sophisticated, but usually small-scale, systems. More recently, in connection with large-scale development programs and government-managed schemes, the planned introduct