A participatory investigation into multifunctional benefits of indigenous trees in West African savanna farmland.

Abstract

Loss of trees has contributed to soil erosion and depletion of soil organic matter and nutrient status across sub-Saharan Africa, enhanced by a period of dependence on subsidized inorganic fertilizer. This paper is based on an eight-year study with farmers on the northern Gambia/Senegal border. It documents farmers' perceptions of past and present farming systems and their attitudes to farmland trees, communicates results of a literature review to them, and facilitates farmer experimentation into the potential of tree leaf mulches for groundnut production. Trees have many use values but little value was initially perceived for farming. Information provided on the use of trees in cropping systems elsewhere in the region was not thought to be relevant locally. The exception was for Faidherbia albida which was initially encouraged for cultural reasons, and tree density increased from one to 17 trees per hectare over the subsequent six years in response to protection by farmers. Farmer experimentation with tree mulches identified Guiera senegalensis as a beneficial species when used in combination with low rate inorganic fertilizer and this species is now valued by some farmers, rather than being perceived as a weed. Such protection of indigenous trees is likely to maintain the natural resource base, benefiting local people and wildlife species associated with the trees, as well as providing ecosystem services that benefit the wider community.