Résumé
Irrigated agriculture covers 18% of cropped areas and produces 40% of world food. Its productivity per hectare is higher than rain-fed agriculture, but constraints are also more demanding: high investment, important running and maintenance costs, intensive cropping systems tightly dependent upon commercial chains, collective management often necessary, sharing water with other users. This special issue gives a non-exhaustive view of new irrigation problematics, current trends, opportunities, challenges and potential problems. Based on case studies in Europe, Asia, North and Sub-Saharan Africa, three main issues are discussed: (i) technical innovation and improvement of irrigation performance; (ii) new land and water management institutions; and (iii) tensions surrounding irrigation issues inside territories.