The contribution of banana farming systems to sustainable land use in Burundi

Two field surveys were conducted in the Kirimiro region in the centre of Burundi. The goal was to study the banana-based cropping systems in the area especially traditional practices of soil fertility management. The region is densely populated and average farm size is 0.88 ha. The number of cattle is declining due to fodder shortage resulting in a decline of manure production. Soil fertility and consequently production is low. Farmers use all sources of organic manure in order to maintain soil fertility such as farmyard manure, compost and crop residues. The limiting factor for manure and compost production is the availability of organic matter. Mulching is used for banana groves and coffee plantations. Under these crops there is hardly any soil erosion. Soil fertility is declining with distance from the homestead. The study revealed four distinct rings of soil fertility status which are again managed in different ways. The area around the homestead is the most fertile, receiving the highest amount of organic manure. The next ring receives already mulch lower rates while distant fields are not fertilised at all, except for some incorporated crop residues or weed. The fourth ring is constituted by pasture and forest, which are sources of organic matter. There is thus a net transfer of fertility from distant fields towards the homestead. Crops are chosen according to the fertility status, i.e. the most demanding crops and especially banana are grown close to the homestead. The authors propose ways of increasing productivity, such as agroforestery, mineral fertilisers, more efficient organic matter recycling and erosion control.