Details on Soil and Water Conservation in Burkina Faso
In 1988, a ten-year program of soil and water conservation was launched in Tahoua, Niger to reintroduce simple, replicable conservation practices. The improvements consisted of increasing their dimensions from a diameter of 10 cm to 20-30 cm, from a depth of 5 cm to a depth of 10-25 cm, to collect and store more rainfall and runoff, and putting organic matter in the pits to improve soil fertility. When the Nigerian farmers returned home, some decided to revive the traditional hand-dug planting pit technique, known locally as tassa. They started with four hectares of land, including one field next to a main road so people travelling by could see the impact. The results were so impressive that the following year tassa use increased to 70 hectares. This was a drought year; only those farmers using tassa had a reasonable harvest. Over the next few years, tassa was instrumental in bringing 4,000 hectares back into production. In 2007-8, tassa has become an integral part of the local farming scene and is still spreading at a rate of about two to three hectares per year.
Source: http://fao08.fidafrique.net/Fiche85-IFAD-PPILDA-SoilFertily-Niger.pdf