De la forêt naturelle aux agroforêts en Guinée forestière

Abstract

A combined agronomic and geographic approach has helped to explain forest agrosystem spatio-temporal dynamics in the forest regions of Guinea. The important expansion of cropping systems associating various perennial crops (coffee, kola, cocoa, fruit trees) and native spontaneous forest species - called "agroforests"- has been observed in 3 villages of the Kobela area. This spatial dynamic can be considered as the renewing of an ecosystem dominated in the past by forest. During the same period of 25 years, the area of food crops on hills based on upland rice after slash and burn has increased slightly. In this case shortening of the fallow period has been observed simultaneously with an increase of cropping duration, leading to a soil fertility decrease trend. On the contrary, agro forests provide environmental services such as maintaining biodiversity and soil fertility, and reducing runoff and erosion. Still, they could also jeopardize food security for rural societies by reducing annual food crop areas, especially in times of an increase in food prices. The challenge is to combine these various cropping systems at the village and farm scale in order to reach both farmer and societal objectives in terms of sustainable development.