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Reviving Agroforestry in the Sahel
Agroforestry is a traditional land-use system that involves retention or introduction of trees or other woody perennials in combination with crop and animal production. The aim is to benefit from related positive ecological and economic interactions. Tree species preserved have economic value – they provide timber, firewood and a host of valuable non-timber products, such as fodder, fruits, gums, etc. – and they play a daily and vital role in the diets and health of the people. The environmental spin-offs of these traditional practices, such as improved soils and protection against desertification, are considerable. But changing circumstances are threatening the efficacy and sustainability of the system.
What remains of the forest in the Sahel is a diverse arrangement of crops and rangelands characterized by a much lower density of trees compared to the situation only a few decades ago. A careful selection of trees has occurred over the generations. The remaining trees reflect their importance according to the social, economic, strategic and religious values of the ethnic groups using the land. The forests have thus been transformed into "parklands" consisting of cropped fields and pastures with scattered trees.
The preservation of these selected trees in the fields protects the sandy soil from the erosion caused by the Harmattan winds, sweeping south from the Sahara during the dry season, and by the torrential downpours in the short rainy season. The trees also help restore soil fertility through biomass production, which also alleviates fodder shortages during the long dry season.
Most of the trees retained are multipurpose trees: in addition to the direct ecological interactions of trees and agriculture discussed above, trees can supply a variety of products and services for many uses and users.
Today, in addition to the natural challenges faced by Sahelian agriculture, such as low and highly variable rainfall with annual droughts lasting nine months and periodic droughts that may last several years, emerging circumstances – such as the growing demographic pressure on land, social rapid changes and new policy environments, along with expanding market forces and cash-crop commercial farming systems – have put a severe strain on traditional agroforestry systems, including the parklands.
Parkland systems are particularly threatened by the combined stress of overgrazing on reduced surfaces and shortened periods of fallow – hindering the natural regeneration of trees – and severe tree lopping for feed requirements of the herds and firewood supply.
Specific technologies predominantly based on traditional knowledge systems have been tested in order to alleviate pressure on the threatened agroforestry systems. Their introduction should follow a holistic approach, taking into account the perspectives of different stakeholders (farmers with different land- tenure rights, herders, women, etc.) in harmony with overall village land-management systems.
IFAD-financed research and development projects are mainly promoting four agroforestry technologies in Sahelian West Africa. These technologies, in addition to the parklands, are represented in the agroforestry model.
Living Fences
Traditionally farmers have used dead wood and some tree species to fence off their plots, marking land tenure rights and boundaries and keeping out free-roaming animals. Much time is spent in collecting the woody material, which is becoming increasingly scarce, and its use puts additional pressure on the remaining natural vegetation.
Research has tested and identified optimal species arrangements and management techniques to obtain a more efficient and lasting protection against livestock that helps farmers grow off-season products and shelters young tree saplings until they reach maturity, in addition to the timber, fruits and ecological benefits supplied by the hedge itself.
The model demonstrates two-layered fencing: an outer wooden fence (from crop residues, branches of woody, thorny tree species) provides a temporary shield protecting the living hedge until it is established. The live hedge is made of two different species: one thorny, woody perennial for protection and another for fodder.
Fodder Banks
In combination with the thorny species selected for the live fence, research has identified highly productive varieties of palatable plants that can add to the vegetables grown inside the protected plots or can be cultivated in a separate and specific site and thus supply much-needed dry-season fodder, as well as a complementary source of revenue.
Nursery Know-How
Farmers are provided with nursery know-how to enable them to master the whole process of live-fence- making and to generate some of the trees to be grown inside the protected plots. The nurseries allow for the selection of superior varieties of multipurpose trees, based on farmer preferences.
Windbreaks
Trees in rows protect the sandy soil from erosion. The soils are vulnerable to Saharan Harmattan winds in the dry season, and protection can make a substantial difference to food crop productivity. Diffusion of this technology would require additional effort in ensuring its compatibility with the requirements of the farming system.
Improved Oven To Save Energy
Traditional cooking practice is replaced with improved ovens, which significantly save energy and therefore reduce the need for firewood.
