Cowpea Production: A Complete Guide

Cowpea, known scientifically as Vigna unguiculata, is a vital legume crop in Kenya. It provides essential dietary protein and income for local communities. Farmers often grow cowpea alongside maize, sorghum, millet, or cassava as part of their subsistence farming. This crop also enhances soil health, helps control weeds, and offers vegetables and dry grain once harvested.

Cowpeas

Cowpea offers several benefits for farmers compared to other grain legumes and vegetable crops. It can withstand drought and high temperatures better than many other legumes. Cowpea has the ability to fix nitrogen from the atmosphere, which helps improve soil health. Additionally, it can be grown alongside other crops since it thrives in shaded areas and grows quickly, reducing soil erosion. This makes cowpea an important part of farming practices in places where soil fertility is low. It is often intercropped with cereals in rotating cycles.

Which is Best: Commercial Fruit Crop Farming Vs Real Estate Investment

Cowpea is very important, yet its yields are often low or even dropping. This is due to factors like poor soil quality, inadequate farming practices, pests, diseases, and ineffective postharvest care. Using better farming methods and improved varieties can significantly cut down on these losses.

Cowpea is high in protein, with some types containing around 30%. It also provides essential micronutrients like iron and zinc, which are vital for good health. Women greatly appreciate cowpea because it helps them get through the "hunger months" before the main cereal harvest and serves as a source of income for both rural and urban families.

Varieties

1. Machakos 66 (M66)

2. Katumani 80 (K80)

3. KVU 27-1

4. Kenkunde

5. KVU 419

6.  Kunde 1

7.  KCP 022

8.  Ngombe

Environmental Requirements

Climatic Needs

Cowpea is adapted to high temperatures in the range, 20℃ - 35℃. It does not withstand flooded conditions. It grows under a wide extreme of moisture, and once established, it is fairly tolerant to drought, and can give good yields under marginal rainfall. Some early and intermediate maturing cowpea varieties can grow and produce seed grain on only 188 mm of annual rainfall. For forage purpose, rainfall of 750 to 1100 mm is preferable. It will tolerate lower rainfall, but in high rainfall areas disease and insect attacks increase. Excessive rainfall also results in the production of too much haulm, delays ripening, and reduces grain yield.

Soil requirements

Cowpea grows well in a wide range of soil textures, from heavy clay if well drained to varying proportions of clay and sand. The crop thrives best in slightly acid to slightly alkaline (pH 5.5–8.3), sandy loam soils. Cowpea can tolerate salinity to some extent, but tolerates soils high in aluminum. The crop is intolerant of water logging and must therefore be grown on free draining soils.

Propagation

Cowpea is propagated by seed, with a seed rate of 8 - 10 kg per acre.

Land Preparation

The land can be manually prepared using the conventional hand tools. In most settings where cowpea is grown on old plots, field preparations start immediately with cultivation or tilling of the land. However, production on virgin land should start with clearance of before proceeding to till the land. Trees and shrubs in the site are cut down manually, or grasses slashed and fallen trees removed from the field. Tractors can also be used to plough, and harrow the land before planting. Ridging can be carried out after harrowing if ridge planting is required.

Fruits Rich in Antioxidants: Healthy Choices in 2024

Land preparation is carried out before planting for the following reasons:

(i) To prepare a suitable seedbed

Seedbed should be soft yet compact enough so that soil particles are in close contact with the seed.  Seedbed must retain sufficient moisture to germinate the seed and support subsequent growth of the seedlings.  Seedbed must prevent surface run-off and wind erosion. Seedbed must not be too compacted; it must allow sufficient entry of oxygen into the soil.

 (ii) Elimination of weed competition

Weeds compete with the crop for water, light and nutrients. They should therefore be destroyed in land preparation.  Weeds with rhizomes and bulbs should be brought to the surface during land preparation to be dried by the sun.

(iii) To improve the physical conditions of the soil.

The physical condition of the soil is improved in land preparation by:  Destruction of native vegetation or removal of residues of another crop.  Removal, burial or incorporation into the soil residues of another crop.  Loosen if the soil is too hard, compact if the soil is too loose. Destruction of hardpan so that water infiltration into the soil is improved.

(iv) Elimination of soil diseases and eggs of insect pests.

The hyphae and spores of fungal diseases and eggs of insect pests are brought to the surface of the soil by land preparation so that they may be killed by the intense heat of the tropical sun.

Planting

Most cowpeas are intersown with other food crops such as sorghum, maize, millet and cassava. Pure stands are sometimes established near homesteads for their leaves to be eaten as vegetable. Early or intermediate cowpea varieties can be planted in maize field. During the harvest of maize crop, the stalk should be cut about 1.5 m tall and left to stand on the field. The maize stalk provides support for the cowpea to grow or climb and produce good quality seed.

(i) Spacing

Spacing in pure stands is very variable, very often 30 cm by 40 cm in off-season and 40 cm by  50 cm for early and erect varieties. A wider spacing of 50 cm by 75 cm for late or spreading varieties with 2 or 3 seeds per hill are commonly used. In some instances, spacing of 60 cm by 30 cm is also reasonable. Broadcasting is the more common method of sowing amongst rural farmers in Africa in particular where cowpea is sown with other food crops.

(ii) Seeding Depth

A seeding depth of 2 cm to 5 cm is recommended; however planting at 3 cm to 4 cm gives good germination hence plant stand.

(iii) Fertilizer

Cowpea grows well without fertilizer in fertile soils. In soils of low fertility, it responds to phosphorus and potash and often to some nitrogen. An amount of about 60 kg per acre of (P₂O₅) applied at the time of sowing and may also be applied before sowing. As a legume, the cowpea fixes its own nitrogen. Too much fertilizer will result into heavy vegetative growth and reduce grain production. Use of at least 2 tons per acre of well decomposed compost or farmyard manure is recommended especially in areas where soils are low in organic matter content. This is best applied under dry conditions and then mixed with the topsoil, about one week prior to planting.

Cowpea Farming Field

(iv) Irrigation

Supplementary irrigation to cowpea field is important.

(iv) Irrigation

Supplementary irrigation to cowpea field is important in areas where annual rainfall is less than 400 mm. During offseason, every other day irrigation schedule is necessary so that the plants can withstand the heat and water stress effect of the dry season high evapo-transpiration rate.

Understanding Water Erosion And Its Global Impact

Weed Control

Weeds are serious problem in cowpea production. If not periodically removed they may act as hosts for pests. Thus they will reduce both yield and quality of the grain. In addition, fodder yield may also be reduced since cowpea is not a strong competitor for resources particularly at the establishment stage. In other words, cowpea should be kept free of weeds after establishment. When left unweeded, cowpea can be completely smothered by weeds resulting in total yield loss. Weeds compete with crop, during growth, for light, water and nutrients. Weeds can cause greater yield reduction than arthropods, bacteria, viruses, fungi and diseases and may lower quality of the produce.

Pests and Diseases

Pests

Pests Insect pests are probably the most important factor limiting the yield of seed and quality of leaves used as vegetable. The most important pests of cowpea include: Bean Aphids, Blossom Beetles, Spotted Pod Borer, Bird damage, Bruchids.

Diseases

Diseases of cowpeas are more prevalent and serious in humid areas but they can also attack the plants in drier areas. The most common diseases that affect cowpea are:

a.  Zonate leaf spots: These are various spots on the leaves caused by Ascochyta phaseolorum and Dactuli phoratarii and pseudo rust (Synchytrium dolichi). Their control is mainly by growing resistant varieties of cowpea to these fungal diseases. Septoria leaf spot, Cercospora leaf spot and brown blotch are some of the common cowpea leaf spots.

b. Viral diseases:  Cowpea is susceptible to more than 20 viral diseases, some of which include: cowpea aphid-borne mosaic, cowpea banding mosaic disease, cowpea chlorotic mottle virus, cowpea golden mottle virus, cowpea yellow mosaic and cowpea severe mosaic virus. Some are passed from one generation of plants to the next through the seed, and as a result, they can spread to other cowpea production areas through seed transfer. Seed borne diseases are spread within cowpea fields by insect pests such as aphids and beetles.

Pest and Diseases Management

Integrated pest management (IPM) combines different methods to control pests and diseases. It includes using plant resistance, physical barriers, cultural practices, biological agents, chemicals, and exclusion techniques. The goal is to keep pest populations low enough to avoid economic damage while protecting non-target organisms, food safety, and the environment.

Monitoring pests and setting action thresholds are crucial in IPM to decide when to apply management strategies. In Kenya, many smallholder farmers do not widely use IPM, which highlights the need for greater promotion. This approach can help reduce pesticide use and improve food and environmental safety.

Harvesting

To make a good vegetable or spinach, the leaves of the cowpea plant must be young and tender; the best leaves are about the third and fourth from the apical end of the shoots. Removing all the tender leaves three times at weekly intervals, starting four or six weeks after sowing (planting) have no adverse effect on grain yields although flowering may be delayed. In crops grown for the seed, 10–20% of the leaves are harvested before the start of flowering with little detrimental effect on the seed yield.

Cowpea Pods

Mature seeds are usually harvested by hand. Green pods are harvested when the seed is still immature, 12–15 days after flowering. Harvest of matured pods for dry seeds are usually done by removing matured pods individually as they ripen and are spread on the ground in the homestead to dry. In indeterminate maturing varieties, harvesting of matured pods is complicated by prolonged and uneven ripening; for some landraces harvesting may require up to seven rounds with three to four days intervals. The duration of the crop from sowing to harvesting depends largely on the growth habit, the rainfall and local husbandry practice but is seldom not more than five or six months.

The yield of cowpeas per acre can vary depending on the variety, the soil fertility, and the amount of rainfall. However, a typical yield is 800-1800 kg per acre.

Post-Harvest Handling

Threshing

The pods of cowpea can be manually threshed by beating with a stick when harvested pods spread in the sun are well-dried. The seeds are breakable as such the threshing should be light, just to break the pods. The pods can also be broken by fingers to remove the seeds, if the quantity is little.

Sorting

Seed quality is a determinant of good crop establishment, growth and development. Thus care at all levels of operations; from harvesting, threshing and post-harvest handling to keep the seeds free of infection by pests and diseases is necessary. Sorting is crucial to remove defective and broken grains, stones, waste and infected seeds from healthy ones. It is in the interest of the seed dealers to get clean seed from seed farmers so that they get better pay. The seeds found in South Sudan markets are not clean; they contain stones, various foreign wastes, broken and defective grains; infected grains with diseases, weevils and bruchids.

Grading

The highly nutritious cowpea seed is grown for fresh, processed, and dried uses. Thus, healthy leaf and high quality seed is required for consumption and marketing. Grading can be done by removing infested, diseased and broken seeds and leaves. Shriveled seeds are also eliminated.

Market

The price of a 90kg bag of beans in Kenya can vary depending on the season, the location, and the quality of the beans. However, a typical price is around Kshs. 2,000  per bag. Selling price per kg ranges between 160 to Kshs. 250.

• Spacing: 30cm by 60cm between rows depending on variety
• Market price: Kshs. 160-250 per kg
• Yield: 800 to 1800 kg per acre
• Common pests: Bean Aphids, Blossom Beetles, Spotted Pod Borer, Bird damage, Bruchids.
• Common diseases: cowpea aphid-borne mosaic, cowpea banding mosaic disease, cowpea chlorotic mottle virus, cowpea golden mottle virus, cowpea yellow mosaic and cowpea severe mosaic virus.
• Lifespan: one growing season

Frequently Asked Questions

• How profitable is cowpeas farming in Kenya?
• How long does it take for cowpeas to grow?
• What are the different types of cowpeas in Kenya?
• How long do cowpeas leaves take to mature?
• How much is a kilo of cowpeas?
• How much do cowpeas produce per acre?
• What is the spacing for cowpeas?
• How do you intercrop cowpeas and maize?