Horizontal flows of nitrogen, potassium, and carbon in urban vegetables gardens of Bobo Dioulasso, Burkina Faso
2019
Lompo, Désiré Jean-Pascal | Compaoré, Emmanuel | Sedogo, Michel Papaoba | Melapie, Martina | Bielders, C. L. | Schlecht, Eva | Buerkert, Andreas
Little is known about matter flows in intensive small scale production systems of urban agriculture in West Africa as an important criterion to assess their sustainability and environmental externalities. This study therefore investigated nutrient management practices in six selected urban vegetable gardens of Bobo Dioulasso, the second largest city of Burkina Faso. Nitrogen (N), potassium (K), and carbon (C) fluxes were quantified and nutrient balances calculated for three gardens representing typical commercial gardening + field crops and livestock systems (cGCL) and three gardens representing commercial gardening + semi-commercial field crop systems (cGscC). Inputs in all gardens exceeded the amounts recommended by the extension service by up to 709% for N and 434% for K leading to horizontal annual surpluses of 1013 kg N ha⁻¹, 879 kg K ha⁻¹, and 25 t C ha⁻¹, while total balances were only positive for N and K, but negative for C. In both systems, apparent nutrient use efficiency was highest for K (85% and 54% for cGCL and cGscC) followed by N (66% and 44%). Management recommendations should be geared towards increasing N efficiencies by better tailoring nutrient supply to crop demands.
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