Content area
More than half the land in the Sahelian zone are degraded with a hard crust on the surface. The first step in reclamation is to break up the crust and then dig out micro-catchments (called demi-lunes) to store run-off water, every five to ten meters. The dimension of the demi-lune varies but are recommended to be two-by-three meters. Trees are planted in the centre of the open side of the demi-lune to avoid waterlogging. International Crops Research Institute for the Semi-Arid Tropics and sian Vegetable Research and Development Center have identified a short duration cultivar of okra from the Birni N'Konni area that is most suitable for production in the zai holes of the BDL.
Full text
More than half the land in the Sahelian zone are degraded with a hard crust on the surface. The first step in reclamation is to break up the crust and then dig out micro-catchments (called demi-lunes) to store run-off water, every five to ten metres. The dimension of the demi-lune varies but are recommended to be two-by-three metres.
Trees are planted in the centre of the open side of the demi-lune to avoid waterlogging. In the area between the demi-lunes, planting pits, commonly known as zai holes, are dug out. A zai is a 20 ? 20 ? 20 cm deep hole and infilled with about 250 g of compost or manure in the bottom and covered with soil. Traditional vegetables are then planted.
Putting the compost in the bottom of the hole encourages the plant to grow an extensive root system so that it can extract more moisture and nutrients. In addition trenches are dug every 20 m down the slope to further harvest run off water.
Two species of trees have been selected so far - Ziziphus mauritiana and Moringa stenopetala. Z.mauritiana is a small tree native to the Sahel but with a wide range of distribution all the way to Thailand. The domesticated varieties bear fruit ten times bigger than that of the wild species. The fruit resembles a small apple in shape and this has prompted the name Apple of the Sahel (Pomme du Sahel in French).
The Z.mauritiana trees are highly adapted to the Sahelian conditions and can be found in regions of 300 mm annual rainfall. They are tolerant to drought, salinity and waterlogging, and send down deep roots that can exploit soil water from great depths. The trees remain green until January, four months after the end of rains. They then shed their leaves and go dormant until the rains start again In June. A mature rain-fed tree can give a yield of up to 20 kg of fruit. Other species of trees are being tried.
M. stenopetala originates in Ethiopia and Kenya. It is a large tree yielding large quantities of leaves that are consumed as a vegetable. Its relative, Moringa oleifera (moringa or horseradish tree) from India is well known in Sahelian countries. In Niger it is the most popular vegetable, and one of the most nutritious. The green leaves and immature pods and seeds are consumed. It has seven times the Vitamin C in oranges, four times the Vitamin A in carrots, four times the calcium in milk, double the protein in milk and three times the potassium in bananas. Moringa leaves also have very high concentration of anti-oxidant
Vegetables
Two traditional leafy vegetables are planted in BDL systems: Senna obtusifolia and Roselle (Hibiscus sabdariffa). In a recent survey of leafy vegetables in Niger, S. obtusifolia came second (after moringa) and Roselle came fourth in preferences by the rural population.
Ten month old Moringa stenopetala on land that has been reclaimed under the BDL system. High yields of nutritious leaves provide high income to farmers.Women sowing Okra in Zai holes. Okra is known locally as Gombo, a popular vegetable.Demi lune full of rainwater.
Okra (Albemoschus esculentus) is a very important part of the local diet. In the Sahel it Is mostly produced by women. The fruit can be dried and stored for long periods of time.
ICRISAT and AVRDC have identified a short duration cultivar of okra from the Birni N'Konni area that is most suitable for production in the zai" holes of the BDL. Unlike the case with cereals and legumes okra seeds are balanced in both tryptophane and in sulfur-containing amino acids.
For more information contact ICRISAT West and Central Africa, BP 12404 Niamey, Niger. Tel: +227 20 722529/ 722725/ 722626; Fax: +227 20 734329; Email: icrisatsc@ cgiar.org; Website: www.icrisat.org
Copyright Research Information Ltd. Jun 2010