Background

The Gambia is a small country of 11,700 km² surrounded on three sides by Senegal in West Africa. It is situated between 13.2 and 13.7^o N latitude. It consists of a 50-km-wide ribbon of land extending eastwards 475 km from the coast and dissected by the River Gambia. It lies within the sahelo-sudan climate zone with 900 to 1400 mm of average annual rainfall. The rainy season extends from late May to early October.

Rice is the staple food in The Gambia. The average annual consumption per capita is 70-110kg. Domestic production lags behind by 60 %, which is met by importation. The national average yield is 2 T/ha in the lowlands, and 1 T/ha in the upland under rain-fed conditions.

In lowland rice farming, water control is the most important management practice that determines the efficacy of other production inputs. Poor drainage that keeps soil saturated is detrimental to crops and degrades soil quality. In many rice irrigation systems in The Gambia, water control is highly inefficient. Drainage mechanisms are dysfunctional or inadequate because farmers believe that rice grows best when water is supplied in abundance. Poor drainage mechanisms makes it necessary for farmers to transplant tall, very old seedlings, usually 4 - 6 weeks old, and 3 – 4 seedlings per hill.

Typical lowland rice field in The Gambia SRI field in Sapu, The Gambia

Rice fields are kept continuously flooded and are flood-free only at time of harvest. This practice is not only wasteful in terms of water use efficiency, but also leads to leaching of soluble nutrients, blocks aerobic soil microbial activities and biological nitrogen fixation as well as slows mineralization and nutrient release from the soil complexes. New management practices that address lowland rice production constraints in The Gambia are needed. The System of Rice Intensification (SRI), used in Madagascar, proposes a methodology that has the potential to increase rice productivity without a high investment in external inputs or introduction of new cultivars. SRI changes the ways in which plant, soil, water and nutrients are managed. In 2000, 2001, and 2002, SRI experiments were conducted in The Gambia. The SRI water management practices of repeated soil wetting and drying were found to be beneficial to rice plant growth probably through increased biological nitrogen fixation, more nutrient availability, profuse root development, increased tillering, and a high panicle setting ratio leading to higher grain yields.

return to home page