1. G-EAU, Univ. Montpellier, AgroParisTech, BRGM, CIRAD, INRAE, Institut Agro, IRD, Montpellier, France
2. Centre for Environmental Economics and Policy in Africa, Agricultural Economics, Extension and Rural Development Department, University of Pretoria, Hatfield, South Africa
3. CIRAD, UMR G-EAU, Hatfield, South Africa
4. Department of Agricultural Economics, Stellenbosch University, Stellenbosch, South Africa
5. Formerly, Centre for Environmental Economics and Policy in Africa, Agricultural Economics, Extension and Rural Development Department, University of Pretoria, Hatfield, South Africa
6. CEE-M, Univ Montpellier, CNRS, INRAE, SupAgro, Montpellier, France
7. Department of Economics, University of Pretoria, Pretoria, South Africa