“…Within the large number of available scientific and 'grey' publications on UPA crop and animal production in West Africa, each study presents a particular set of data for a well-defined production context and for specifically defined research questions. These cover practically all aspects of UPA, such as appropriate dosing of mineral fertilizers (Drechsel & Zimmermann, 2005), targeted application of organic manure to vegetable gardens (Drechsel, Abaidoo, Amoah, & Cofie, 2000), improved urban milk production (Millogo, Ouedraogo, Agenäs, & Svennersten-Sjaunja, 2008;Sidibe, Boly, Lakouetene, Leroy, & Bosma, 2004) and the externalities linked to wastewater reuse in vegetable cultivation (Eaton & Hilhorst, 2003;Niang, Diop, Faruqui, Redwood, & Gaye, 2002;Sonou, 2001). However, these individual case studies often ignored the interdependencies of bio-physical and socio-economic conditions at the scale of a farm and a town, and the interrelatedness of plant and animal production as well as the interrelatedness of resource use efficiencies and externalities in production processes.…”