Forecasts on population growth and economic development indicate that there will be substantial increases in food demand for the forthcoming decades. We focus here on the water requirements of food production, on the issue of whether there would be enough water to produce sufficient food in the future, and we offer options to face this challenge based on recent trends observed in some agricultural systems. Given the competition for water faced by the agricultural sector, and the uncertainties associated with climate change, improving the efficiency of water use in both rain-fed and irrigated systems is the main avenue to face the challenge. In rain-fed agriculture, managing the risk associated with rainfall variability is a promising option to increase productivity. In irrigated systems, a case study on the improvements in water productivity in Andalusia, Spain, is used to illustrate some of the opportunities to make progress. Progress in reducing irrigation water use in recent decades has been substantial, but decreasing the consumptive use of crops is a much more difficult challenge. The need for more research and technology transfer on improving water-limited crop production is highlighted, and emphasis is placed on interdisciplinary approaches to gain the insight needed to achieve new breakthroughs that would help in tackling this complex problem. © 2011 The Author. | The support of a Consolider-Rideco grant CSD2006-0067 from the Ministry of Education and Science of Spain is gratefully acknowledged. | Peer Reviewed

The water footprint (WF), defined as the volume of water used per unit food produced, is becoming a popular indicator in a variety of assessments that relate food production to water use. The complexities underlying the phrase “water used” already point to the difficulties in computing an indicator with robust and general meaning. | Peer reviewed

Trabajo presentado en el 12th Dahlia Greidinger Memorial Symposium (Water-Soil-Nutrients: Integrated Solutions for Assuring Global Food and Water Security), celebrado en Haifa (Israel) del 29 de febrero al 2 de marzo de 2016. | No

Comunicación presentada en el 8º Foro Agua para el Desarrollo, celebrado en Madrid el 5 de junio de 2013. | Peer Reviewed

Trabajo presentado en la Final EURO-AGRIWAT Conference (Water Footprint of agricultural products: progress, challenges and solutions), celebrado en Wageningen del 7 al 9 de marzo de 2016. | Crops consume large amounts of water as determ ined largely by the en vironments in which they are grown. The introduction of the water footprint concept should have conveyed this reality to the general public; nevertheless, urba nites are often surprised by the magnitude of crop consumptive use, as exemplified by the barrage of media articles criticizing the excessive consumption of almonds in the rece nt California drought. Pressures from other sectors of society and water scarcity due to periodic droughts will force farmers to optimize the use of water in crop production. All optimization approaches must be based on knowledge on the yield response to water and, in turn, on the physiological and agro nomic factors determining such response. The ultimate goal is to be able to accurately assess the economic returns of using different amounts of irrigation water and to evaluate th e risks/rewards of seekin g/acquiring additional supplies in the event of a drought. The presentation will review the state of the art in predicting crop yield response to water using empirical and mechanistic approaches, and will analyze the role of key physiological and agronomic processes in improving the efficiency of water use in crop prod uction in the future. | No