C’est aujourd’hui une nécessité pour une chaîne de valeur agroalimentaire que d’établir et déployer une stratégie de durabilité cohérente pour ses différentes parties prenantes et de parvenir à communiquer sur les efforts conduits auprès des citoyens et consommateurs, dont la demande de produits plus durables est croissante. Pour aller au-delà des premières initiatives existantes (cahiers des charges, labels, etc.), et accroître de façon effective leur performance durable et la qualité perçue de leur offre, envisager de nouveaux outils de gestion, construits conjointement entre l’amont et l’aval peut être une solution. Or les acteurs de ces chaînes, aux intérêts et cultures différents, ont notamment des visions individuelles de la durabilité. Par conséquent, s'ils veulent coopérer pour l’amélioration de la performance durable de leur chaîne de valeur, ils doivent répondre à un niveau minimum de satisfaction de chacun d’entre eux. Ce travail cherche à proposer de nouveaux outils de gestion standardisés et interopérables aux chaînes de valeur alimentaires afin qu’elles puissent co-créer de la valeur durable partagée et s’orienter vers de nouveaux modes de gouvernance.Le contexte expérimental est celui d’une chaîne de valeur de porc français, dont les acteurs entretiennent des relations contractuelles et ont déjà engagé un travail conjoint sur la durabilité de certains produits. Une première contribution porte sur la réflexion pour construire une métrique d’évaluation de la performance durable des chaînes de valeur alimentaires. Les trois cas suivants portent sur les possibilités pour les acteurs d'une chaîne de valeur alimentaire de coopérer dans le partage de solutions d'amélioration de la durabilité. Un scénario témoin est comparé avec plusieurs scénarios d’amélioration de la durabilité et les résultats sont confrontés aux attentes respectives des différents acteurs de la chaîne de valeur. Une quatrième partie s’intéresse l'importance du partage de données standardisées entre les différents acteurs pour soutenir la performance durable. Enfin une dernière section propose un modèle d’appui à un travail participatif pour faciliter la définition d’une stratégie commune de durabilité. / It is now necessary for an agrifood value chain to set-up and develop a coherent sustainability strategy for its various stakeholders and to communicate on the efforts made towards citizens and consumers, in demand for more and more sustainable products. To go beyond the first existing initiatives (specifications, labels, etc.), and effectively increase both their sustainable performance and the perceived quality of their offer, considering new management tools, built jointly between upstream and downstream can be a solution. However, the actors in these chains, with different interests and cultures, have individual visions of sustainability. Therefore, if they want to cooperate in order to improve the sustainable performance of their value chain, they should meet a minimum level of satisfaction for each of them. This work aims to propose new standardized and interoperable management tools for food value chains so that the actors can co-create shared sustainable value and move towards new modes of governance.The experimental context is French pork value chains, whose actors maintain contractual relations and have already tackled joint work on the sustainability of certain products. A first contribution focuses on reflection to build a metric to evaluate the sustainable performance of food value chains. The three following cases are dealing with the possibilities for actors in a food value chain to cooperate on common solutions for sustainability improvement. Contrasted alternative scenarios are compared between them and the results are confronted with the respective expectations of the different actors in the value chain. A fourth section focuses on the importance of standardized data sharing among the various actors to support the sustainable performance. Finally, a final section proposes a support model for participative work in order to facilitate a common strategy definition for sustainability.

Land degradation is a great threat to the Beshlo Catchment in Blue Nile Basisn, not merely as an environmental issue, but also a social and economic problem. In Gedalas Watershed (one of the micro catchments of Beshelo), land degradation, mediated by both biophysical and socio-economic drivers, is among the major environmental sustainability and social-economic development threats in the area. The threat is manifested in depletion of natural vegetations, water, soil and other natural resources; disruption of ecosystem functions, processes, integrity, and services. Given its particular vulnerability, watershed management activities have been in operation since the mid-1970s. Recently, the idea of Sustainable land management through integrated watershed development program has been initiated with the objective of reducing land degradation risks and ensuring food security at both the nationwide and family circle. Despite these investments and efforts, real evidences of success and failures of such efforts were not satisfactory explored. The objectives of this study were, therefore, to analyze the existing status and future prospects of sustainable land management and evaluates its implication on the environmental integrities and the local livelihoods specific to Gedalas watershed. For this effect, the study investigated the dynamics, deriving forces and implications of LULC, soil erosion and soil fertility status of the watershed, current status of watershed management practices, pertinent challenges and opportunities for practicing land management technologies and approaches that might help meet the sustainability requirements of SLM practices. In addition, the study explored factors that determine the willingness of farming households to undertake SLM practice. As the study carried in the coupled human-environment system of rural landscapes, interdisciplinary geographical approaches which integrats social and natural science methodologies were employed to deal with issues of land degradation-and-rehabilitation status comprehensively. The general findings of the study show that though it would be dificult to measure all the composite aspects of land degradation, some of the parameters considered in this study revealed that land degradation is a perpetuating challenge in the watershed. It is evidenced from the overall undesirable land use/cover changes i.e transition of 21.25% of Afro/sub alpine landscapes, 17.59% of the grasslands and 8% of shrub lands to either to cultivated land or settlement areas over the 1973–2017 period, which have unintended negative socio-ecological repercussions on the watershed; high annual mean soil loss value (which range from 37t/ha/year average values to 393 t/ha/yr soil loss rates on water courses) that exceed threshold level and a wide gap between the need for SLM and the actual achievement of SLM practices,including limited adherence to the idea behind contemporary land management policies and implementation principles and approaches. The study further revealed the presence of opportunities as well as a myriad of challenges that need to be tackled in order to achieve sustainable land management goals. The study colcludes that, though, some encouraging progresses have been observed in the SLM project sites; land degradation has remained a problem in the watershed. This calls for strenuous efforts to promote and assist wide scale adoption of SLM practices that address the pervasive land degradation problem and achieve land degradation neutrality as highlighted in sustainable development goals. / Department of Geography / Ph. D. (Geography)