How it began
In 1979 Oxfam began funding the Agro-Forestry Project (PAF), based at Ouahigouya in Yatenga Province. It started as a tree planting project, but villagers said their urgent need was food. Farmers in the area had traditionally laid simple lines of stones in fields to reduce erosion, a practice that had largely been forgotten. Through discussion with villagers the project revived it and improved it by building the lines carefully along the contour, laid out with a simple water-tube level. Contour stone bunds became the main focus of the project from 1982.
Before it existed
A large project of the 1960s, called GERES, had used heavy machinery to build earth bunds over whole catchments in the region, without the participation of local people. Those bunds were designed to drain runoff away from fields. When rainfall diminished in the following years, farmers wanted the opposite, more water on their fields, and they did not maintain the structures, which soon lost their effect.
How it works
A contour is a line across land at equal height. Villagers find it with a water-tube level, a length of clear tube filled with water whose two ends show when two points are level. Stones are then built into a low bund along that line. When runoff reaches the bund it spreads out and trickles slowly through the gaps between the stones, so more water soaks into the soil. Eroded soil, plant debris and manure carried by the water are filtered out and build up behind the bund, improving the soil.
How it spread
The project trained extension agents of three government services in Yatenga, and later people from other regions of Burkina Faso and from other countries. During the first eight months of 1990, fifteen groups from six countries visited. Oxfam later wrote that by 1992 the technique of building stone diguettes along contour lines had won international acclaim and many imitators.
What changed first
The bunds, combined with zaï planting pits, raised yields in the first season after treatment, by 40 to 60 percent according to the project, and treated fields gave some harvest even in very dry years. A 1986 survey found treated plots yielding an average of 972 kg per hectare against 612 kg on untreated plots. By the end of 1989 about 8,000 hectares in more than 400 villages had been treated, and over 5,000 people had been trained to survey contours and build bunds.
What lasted
FAO described the project as having a reputation as one of the most successful soil and water conservation efforts in sub-Saharan Africa, and credited this to simple, cheap techniques based on traditional practice and carried out by villagers themselves. Limits were also noted: the method depends on a supply of stone, bunds silt up after several seasons, and the poorest farmers could not always feed the work groups that build them.
