occur in the nodules formed on the roots. They will often grow well on soils with a low nitrogen content.
On rich soils legumes often produce heavy leaf growth but few seeds some of the more important legumes grown in West Africa.
Cowpea: (Cultural and environmental requirements)
This is an increasingly important crop in West Africa, the leaves and seeds being used for food prepared in various ways; dwarf, tall and prostrate cultivars are cultivated, some are resistant to eelworm. The leaves are used as a fodder for cattle and the seeds are also ground and mixed with other materials in the preparation of livestock feeds.
The seeds are sown on soils of moderate fertility since excessive nitrogen in the soil promotes leaf rather than seed production.
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Many new cultivars have been produced in recent years by Research Stations and the use of some of these has resulted in considerable yield increases.
Many of these cultivars are resistant to 'shattering' or early shedding of the seeds when ripe. Three seeds per station are normally sown either as a single crop or interplanted with maize or yams. Weed control is required until the crop becomes established, and any plants which are infected with virus mosaic disease should be uprooted and burned.
Harvesting is by hand, several successional harvests being required since all of the pods do not ripen uniformly, except for those of some of the newer cultivars. The pods are threshed by hand and the seeds stored after being well dried in the sun; they are sometimes heated to destroy the eggs of insects, but may also be treated with insecticide if required for seed.
The cowpea makes a good cover crop and is useful for inclusion in rotations.
Groundnuts: (Cultural and environmental requirements)
The groundnut is widely grown in many parts of West Africa, particularly in northern Nigeria. Two main types are in cultivation: the prostrate or runner and the erect or bunch types which may reach a height of 45cm.
Groundnuts thrive in wells drained sandy loams and crops in many types of soil respond to fym applied before planting and also to dressings of phosphoric fertilisers after sowing. Seeds are sown, often in shell, at two per stand, either on mounds or ridges 1m apart. Seed dressings against soil fungi have been found to increase yields. The soil around the base of the plants should be regularly hoed before the flowering period since the fertilised flowers recurve and bury themselves in the soil; this also assists in reducing weed growth. The crop is harvested by hand, except on large-scale farms where lifting implements are sometimes used. The whole plant is lifted and dried in the field for several days before the nuts are separated from the haulm or stems. Inadequately dried and stored nuts may develop a fungus which can produce a poisonous substance.
Rosette virus disease can be partially controlled by early and close planting, the use of diseases free seed and the removal and burning of infected plants will also assist in controlling this disease. Crop rotation and early planting also reduce the severity of Tikka disease which is caused by a fungus. Most pests of groundnut are active in the posts harvest stage and can be largely controlled by applying insecticide to containers and storage areas generally.
Bambara groundnut: This crop has a lower oil content than the groundnut but it is often grown on soils which are less fertile than those used for groundnuts. Seeds are sown during the early rains, usually on ridges, two or three seeds are sown and later thinned to leave the most vigorous seedling. Weeds should be controlled and the soil well hoed around the base of the plants. Fertilisers may be used but the value of the crop rarely justifies the costs involved. The plants arc harvested and the nuts dried in the sun, as for groundnuts.
The soya bean is not widely used in West Africa as a food crop, although it is a valuable constituent of livestock foods, but is grown mainly as an export or cash crop. Dwarf cultivars have been recently produced which grow well in most areas. The seeds are high in oil and protein content, which is typical of many members of the Leguminous family.
Groundnuts thrive in wells drained sandy loams and crops in many types of soil respond to fym applied before planting and also to dressings of phosphoric fertilisers after sowing. Seeds are sown, often in shell, at two per stand, either on mounds or ridges 1m apart. Seed dressings against soil fungi have been found to increase yields. The soil around the base of the plants should be regularly hoed before the flowering period since the fertilised flowers recurve and bury themselves in the soil; this also assists in reducing weed growth. The crop is harvested by hand, except on large-scale farms where lifting implements are sometimes used. The whole plant is lifted and dried in the field for several days before the nuts are separated from the haulm or stems. Inadequately dried and stored nuts may develop a fungus which can produce a poisonous substance.
Rosette virus disease can be partially controlled by early and close planting, the use of diseases free seed and the removal and burning of infected plants will also assist in controlling this disease. Crop rotation and early planting also reduce the severity of Tikka disease which is caused by a fungus. Most pests of groundnut are active in the posts harvest stage and can be largely controlled by applying insecticide to containers and storage areas generally.
Bambara groundnut: This crop has a lower oil content than the groundnut but it is often grown on soils which are less fertile than those used for groundnuts. Seeds are sown during the early rains, usually on ridges, two or three seeds are sown and later thinned to leave the most vigorous seedling. Weeds should be controlled and the soil well hoed around the base of the plants. Fertilisers may be used but the value of the crop rarely justifies the costs involved. The plants arc harvested and the nuts dried in the sun, as for groundnuts.
Soya Bean: (Cultural and environment requirements)
The soya bean is not widely used in West Africa as a food crop, although it is a valuable constituent of livestock foods, but is grown mainly as an export or cash crop. Dwarf cultivars have been recently produced which grow well in most areas. The seeds are high in oil and protein content, which is typical of many members of the Leguminous family.
The seeds are sown, either broadcast on the flat or on ridges up to 1m apart, in soils which have a fairly high organic content. The crop generally responds to phosphoric fertilisers and routine cultivations such as weeding should be continued until the leaves cover the soil surface. Pests can be controlled by regular spraying, diseases such as wilt should be reduced in severity by using clean seed and crop rotation.
The newer dwarf cultivars, the pods of which mature uniformly, are normally harvested by uprooting the whole plant.
The newer dwarf cultivars, the pods of which mature uniformly, are normally harvested by uprooting the whole plant.
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Mechanised methods of harvesting can also be used. The seed pods, when dry, are threshed by beating and the seed stored in cool conditions. (Cultural and environmental requirements) This unusual type of legume produces both edible white or speckled seeds and a large tuber which can be eaten in either the raw or cooked state. It is often grown as an intercrop with yams, the stakes of which provide support. Sandy, well-drained loam soils are
most suitable for this crop and fertilisers containing both potassium and phosphate can promote rapid growth. Seeds are sown at the beginning of the rains and, if large tubers are required, the tops of the plants can be removed at a height of about 1-1.5 m.
Pigeon pea (Cultural and environmental requirements) :
This crop is widely grown in West Africa and is known as the Congo bean in some areas. It is sometimes grown as a garden crop and the leaves are used as animal fodder.
Pigeon sometimes being interplanted with yams. The deeply pea is useful in rotations or as a cover crop, penetrating roots are useful for breaking up hard soils. The best yields are obtained from fertile soils with a good content of organic material, but the pigeon pea is tolerant to a wide range of soil conditions.
Seeds are sown on ridges or on flat land at the beginning of the rains and weeds should be controlled until the plants are established. Plants are fairly short lived and rarely produce many seeds in the third year of growth although some newer cultivars may survive for longer periods. Cutting back plants to 30-40 cm from ground level results in the production of new flowering branches. The plants may be sprayed with fungicide or insecticides to control diseases and pests but their value rarely justifies this expenditure. Seeds should be thoroughly sun-dried and treated with insecticide if being kept for sowing.
Seeds are sown on ridges or on flat land at the beginning of the rains and weeds should be controlled until the plants are established. Plants are fairly short lived and rarely produce many seeds in the third year of growth although some newer cultivars may survive for longer periods. Cutting back plants to 30-40 cm from ground level results in the production of new flowering branches. The plants may be sprayed with fungicide or insecticides to control diseases and pests but their value rarely justifies this expenditure. Seeds should be thoroughly sun-dried and treated with insecticide if being kept for sowing.