Matter flows and balances in urban vegetable gardens of Bobo Dioulasso, Burkina Faso (West Africa)

In sub-Saharan Africa, urban and peri-urban agriculture (UPA) is practiced as a survival strategy for the urban poor dwellers. Numerous studies provided quantitative and qualitative data on the social, economic and environmental characteristics of UPA thereby improving our knowledge on this type of agriculture. However, there is still a gap of more comprehensive solid data, especially regarding nutrient flows and balances which are indicators necessary for developing management practices to improve the sustainability of UPA activities. This PhD research investigated through horizontal nutrient balance approach, the sustainability and efficiency of use of nitrogen, phosphorus, potassium and carbon in diverse UPA production systems including “commercial gardening + field crops and livestock” and “commercial gardening + semi-commercial field crops”. Moreover, gaseous emissions of nitrogen and carbon were measured in such enterprises using a closed chamber system. The results showed that nutrient management practices in UPA systems of Bobo Dioulasso would greatly benefit from better synchronizing nutrient input rates with crop demands and adjusted fertilization techniques to mitigate nitrogen losses.