Is the daunting challenge of irrigation achievable?

The projections of food and water demand for 2025, which conclude that irrigated areas should increase by 15 to 22%, assume that the productivity of present irrigation should also increase at unprecedented rates. This paper discusses some of the reasons why the contribution of irrigated agriculture to food and fiber production has continued to increase despite the lower level of investments for developing new irrigable areas and the focus on rehabilitation of existing schemes. The shortages of food production projected for the 1990s have been averted because of the explosive exploitation of groundwater and the many‐fold increase in water‐saving application techniques over the last three decades. However, overexploitation of aquifers and an associated decline in water quality have been occurring in many parts of the developing and developed world, particularly in the semiarid regions. This paper suggests that no further complacency in addressing the long due issue of the poor management practices of the large irrigation systems is acceptable. The failures to understand the links between the technical improvements of the large surface irrigation schemes and required reforms may exacerbate the problem of water scarcity and threaten food security in the future. Development of reliable irrigation in surface systems is crucial to realizing the challenge of irrigation. The magnitude of investments and capacity building in human resources to achieve this goal is likely underestimated. Copyright © 2002 John Wiley & Sons, Ltd. RÉSUMÉ Les études sur les prévisions de la demande en eau et des besoins alimentaires pour l'année 2025 concluent que les superficies irriguées doivent s'accroître de 15 à 22 pour cent. Ces prévisions prennent pour hypothèse que la productivité des superficies actuellement irriguées devra augmenter à un rythme bien supérieur à celui observé dans le passé. Cet article présente quelques‐unes des raisons pourquoi la contribution de l'agriculture irriguée a continué de progresser malgré le faible niveau des investissements pour mettre en valeur des nouvelles surfaces irrigables et malgré l'attention portée à la simple remise en état des périmètres existants. Le déficit de la production alimentaire prévu dans les années 1990 a été évité grâce au développement explosif des eaux souterraines et à l'adoption des techniques économisatrices d'eau dans les trente dernières années. Cependant la surexploitation des nappes et la détérioration de la qualité