Agrinews January 2013 - Ministry of Agriculture

BAMBARA GROUNDNUT
Background Information
Bambara groundnut is an indigenous legume of Africa
which originated from the Sahelian region of present day
West Africa. Through migration, people brought the crop
to southern Africa many years ago. In Botswana, Bambara
groundnut is known as jugobean or ditloo. It is related to
cowpea. Thus, botanically it is called Vigna subterranean
(L.) Verdc. In Botswana, it is found in various landraces
and farmers grow it in mixed/intercropped/sole cropped
systems mainly for consumption and sale. On average,
farmers get yields of about 200 kg/ha. In 2008, the two
most promising varieties namely Keledi (MA -15A) and
Mokgalo (N-100) were released.
Plant Characteristics
Bambara groundnut is a herbaceous annual legume with
compact well-developed tap root with many short lateral
stems on which the leaves are borne. The released varieties
are bunchy type and are self-pollinated. The crop forms
pods below the soil surface or just above the ground
and majority contain one seed. The pod colours of the
released varieties are creamish for Keledi and purplish for
Mokgalo. Seed colours are cream with a v-shaped purple
colour surrounding a white eye for Keledi and completely
purple with a white eye for Mokgalo
Growth and Development
Seed germination takes 7-15 days. Flowering starts 30 to
45 days after sowing and may continue until the plant
matures. Pod and seed development take place about
30 to 40 days after fertilization. Maturity varies with
landraces and seasons and may go up to 180 days. The
released varieties mature between 130-150 days
Mokgalo tend to flower, pod and mature earlier than
Keledi. The crop is a typical short-day plant, that is, long
days may delay/prevent flowering and podding.
Soil and Fertilizer Requirements
The crop is adapted to a wide range of soils, but
welldrained soils, sandy loams with pH of 5.0-6.5., soils
rich in phosphorus and potassium are most suitable.
Yield potential is reduced when grown in sandy clay
loams,. It performs well in poor soils with low nutrients.
But in soils with abundant nitrogen, the crop grows
vegetatively while in calcareous soils, it grows poorly.
Chemical fertilizer recommendations in Botswana are
lacking because the crop does not give significant
responses.
Climatic Requirements
Bambara groundnut requires warm temperatures of 20
to 280C and does not tolerate freezing temperatures at
any stage of growth. It is most suited for hot dry areas
and thrives well in marginal rainfall conditions too dry
for sorghum, maize and groundnut. However, for better
performance, the crop requires an average rainfall of
about 600 to 700mm during the growing period. Too
much rain at harvest time may result in yield losses.
Planting
Plant seeds in a deeply ploughed field with a fine seedbed.
Planting should be done around October/ November
after good rains. The seed rate for the released varieties
is 50 kg/ha but can vary with seed size and according to
literature it varies for small or big seeds from 25-75 kg/
ha. Seeds for planting should be treated with fungicide
and planted at a depth of 2.5-3.0 cm in heavy soils and
5.0 – 7.5 cm in sandy soils. Hand hoe or planters with
correct plates can be used to plant seeds. Recommended
spacing for the released varieties is 75 cm inter-rows by
20 cm within rows in order to get 67,000 plants/ha.
Yields and Nutrition
Yields depend on variety and environmental conditions.
Recommended variety yields ranged from 0.1-3.6 t/ha
under rain fed. But elsewhere under irrigation, a yield of
4.2 t/ha, has been reported. Mokgalo tend to out yield
Keledi when they are grown under similar conditions.
Seeds are nutritious and provide a balanced diet.
They contain sufficient quantities of protein (16-25%),
carbohydrates (50-69%), oil (6-12%) and minerals such as
calcium, potassium, phosphorus, magnesium, iron and
sodium. Haulm can be used to feed livestock. Due to its
ability to fix nitrogen, Bambara groundnut is useful in crop
rotation.
The Director Department of Agricultural Research Private Bag 0033, Gaborone. Phone: 267-366-8100 Fax: 267-3928965
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