Ecological and social interactions in sustainable agroforestry management: Cocoa in Ghana

Farm management strategies in regions of high ecological and economic risk require solutions for enhanced agroecosystem functioning and sustained rural livelihoods. This may be achieved with agricultural diversification employing agroforestry principles. Accordingly, my research investigates ecological and social interactions in agroforestry systems at multiple scales: from the farm to the community. This thesis involves a social-ecological systems approach, employing cocoa-shade agroforestry systems in Ghana as a case study, to (1) empirically examine biomass production, and nutrient and non-nutrient resource interactions in both early growth and mature agroforestry systems, and (2) examine the transfer and use of local knowledge pertaining to agroforestry practices in agrarian communities. Through vector analysis, I found nearly consistent non-competitive nutrient interactions between cocoa and shade trees during both the early stages of growth, as well as in mature plantations. When fertilizers are undesirable or unavailable, intercropping of appropriately selected shade trees will not competitively suppress early growth of cocoa, but will improve light regulation, sustain nutritional status of cocoa saplings and increase on-farm cocoa biomass as the farm matures. Evidently, target species productivity and nutrition is dependent on dynamic farmer management. Social network analysis showed that locally derived and externally sourced information on farm management circulates through distinctly structured informal advice networks. Such knowledge, particularly ecologically-based on-farm indicators, informed farm management decision making for sustainable resource-use systems. As an analytical concept, management processes offer an entry point into the understanding of human interactions with the environment. Therefore, results were incorporated into a conceptual framework which affords a systematic basis for promoting sustainable and decentralized agroforestry management. This framework also presents an approach for scaling-up results to the landscape level. This research provides effective strategies for agroforestry system productivity, diversity, and resilience by employing a social-ecological approach to sustainable local and regional agrarian practice.