Vincent Vadez, Raphael Pilloni, Alexandre Grondin, Amir Hajjarpoor, Hatem Belhouchette, Youssef Brouziyne, Ghani Chehbouni, Mohamed Hakim Kharrou, Rim Zitouna-Chebbi, Insaf Mekki, Jérôme Molénat, Frédéric Jacob, Jérôme Bossuet, Diversité, adaptation, développement des plantes (UMR DIADE), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD [France-Sud])-Université de Montpellier (UM), International Crops Research Institute for the Semi-Arid Tropics [Inde] (ICRISAT), Consultative Group on International Agricultural Research [CGIAR] (CGIAR), Centre d'Etude Regional Pour l'Amelioration de l'Adaptation A la Secheresse (CERAAS), Institut Sénégalais de Recherches Agricoles [Dakar] (ISRA), LMI Adaptation des Plantes et microorganismes associés aux Stress Environnementaux [Dakar] (LAPSE), Institut de Recherche pour le Développement (IRD), Agrosystèmes Biodiversifiés (UMR ABSys), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Centre International de Hautes Etudes Agronomiques Méditerranéennes - Institut Agronomique Méditerranéen de Montpellier (CIHEAM-IAMM), Centre International de Hautes Études Agronomiques Méditerranéennes (CIHEAM)-Centre International de Hautes Études Agronomiques Méditerranéennes (CIHEAM)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro Montpellier, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), International Water Management Institute, MENA Office (IWMI), Université Mohammed VI Polytechnique [Ben Guerir] (UM6P), International Water Research Institute (IWRI), Institut National de Recherche en Génie Rural Eaux et Forêts (INRGREF), Ecole Nationale du Génie Rural, des Eaux et des Forêts (ENGREF)-Institution de la Recherche et de l'Enseignement Supérieur Agricoles [Tunis] (IRESA), Laboratoire d'étude des Interactions Sol - Agrosystème - Hydrosystème (UMR LISAH), Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro Montpellier, Independent Consultant, The paper was written and supported under the Make Our Planet Great Again (MOPGA) ICARUS project (Improve Crops in Arid Regions and future climates) funded by the Agence Nationale de la Recherche (ANR, grant ANR-17-MPGA-0011), and written in the scope and with the support of the ClimBeR initiative of the CGIAR, itself supported by the France-CGIAR action plan on Climate Change., ANR-17-MPGA-0011,ICARUS,Improve Crops in Arid Regions and future climates(2017), Centre International de Hautes Etudes Agronomiques Méditerranéennes - Institut Agronomique Méditerranéen de Montpellier (CIHEAM-IAMM), Centre International de Hautes Études Agronomiques Méditerranéennes (CIHEAM), and Institut de Recherche pour le Développement (IRD)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut Agro - Montpellier SupAgro
International audience; Highlights:This paper reviews ways to improve water use efficiency beyond the plant level, across time and space scales, from cells, organs, and plants, to field, farm, and landscape.Abstract:Water scarcity will be one of the main issues of the 21 st century, because of competing needs between civil, industrial, and agriculture use. While agriculture is the largest user of water, its share is bound to decrease as societies develop. Clearly, agriculture needs to become more water efficient. Improving water use efficiency (WUE) at the plant level is important although there is a long way into translating this at the farm/landscape level. As we move up from a cell/organ/plant scale to more integrated scales such as plot, field, farm system, and landscape, other factors need to be considered, including trade-offs, to possibly improve WUE. These include choices of crop variety/species, farm management, landscape design, infrastructure development, ecosystem functions, where human decisions matter. This review is a cross-disciplinary attempt to analyze ways to address WUE at these different scales where metrics of analysis are defined and trade-offs considered. The equations in this perspective paper use similar metrics across scales for an easier connection and are developed to highlight which levers, at different scales, can improve WUE. We also refer to models operating at these different scales to assess WUE. While our entry point is plants and crops, we scale up the analysis of WUE to farm systems and landscapes.