1. Institute for Research and Development (IRD), DIADE Research Unit, University of Montpellier , 34394 Montpellier cedex 5 , France
2. International Crops Research Institute for the Semi-Arid Tropics (ICRISAT) , Patancheru, Telangana , India
3. Centre d’Etudes Régional pour l’Amélioration de l’Adaptation à la Sècheresse (CERAAS), Campus ENSA , Thiès , Sénégal
4. Department of Horticulture, University of Florida , Gainesville FL , USA
5. Physics of Soils and Terrestrial Ecosystems, Department of Environmental Systems Science, ETH Zurich , Zurich , Switzerland