Introduction to Cowpeas:
Here you can find some basic information of Growing Cowpeas.
The Cowpea is as a crop plant since Neolithic times. The Cowpeas can be cultivated in the tropics and subtropics. The Cowpea is believed to have originated from West Africa and is cultivated by wild and cultivated species. It is grown widely East and Central Africa, India, Asia, South and Central America.
Cowpea Plant Description:
The Cowpea is an annual herb plant that has varying growth habits. The plant can be erect, trailing, climbing or bushy. And is indeterminate when it cultivated in suitable growing conditions.
- Root: Cowpea plants have a taproot and many spreading lateral roots in surface soil.
- Leaves: The first pair of leaves of a Cowpea plant is opposite arranged, while the remaining leaves have an alternate patterns and are trifoliate. The leaves of the plants will be in dark green in color. The size of the leaves is 6 to 16 x 4 to 11 cm and have many shapes vary from linear, lanceolate to ovate. The leaf petiole is 5 to 25 cm long.
- Stems: the stems of the Cowpea plants are striate, smooth or slightly hairy in purple shade.
- Inflorescence: Flowers are borne in alternate pairs, with usually only two to a few flowers per inflorescence. Flowers are conspicuous, and self-pollinating, and the flowers have short pedicels and the corollas in colors like white, dirty yellow, pink, pale blue or purple.
- Fruit and seeds: Seeds have many sizes, shape and colors. Usually the number of seeds in a pod may vary from 8 to 20. The seeds are 2 to12 mm long and weigh 5 to 30 g/100 seeds. The testa (outer cover) may be smooth or wrinkled; white, green, buff, red, brown, black, speckled, blotched, eyed (hilum white, surrounded by a dark ring) or mottled in color.
- Fruit: pods of Cowpeas vary in size, shape, colors and texture. They may be erect, crescent-shaped or coiled. Usually yellow when ripe, but may also be brown or purple in color.
Varieties of Cowpeas:
There are many Cowpea cultivars are a vining plant. Some modern plant varieties are upright, bush-type cultivars. The vining variety plants are generally preferred for foraged or cover crop cultivation, And the bush variety plants suitable for direct cultivation. Below are some growing species that are suitable for commercial categorized based on bean shape, size and color.
- Black-eyed or pink-eyed/purple hull peas — these Cowpeas come in white with a black eye round the hilum. The “eye” has many colors: pink, purple or shades of red are mostly commonly found variety. When dried, the eye color darkens to a dark purple. The pods will be in purple color with pink-eyed/purple hull type. The seeds are loosely packed and are crowded in the pod and these seeds are in the shape of a kidney.
- Brown-eyed peas — the pods are these varieties comes in many colors, from green to lavender. The seeds are in brown color and when cooked, they change to dark brown, very tender and have a delicate flavor.
- Crowder peas — these Cowpeas or black, speckled, and brown or brown-eyed. The seeds loosely packed and are “crowded” in the pod and have a globular in shape.
- Cream Peas—these Cowpeas are in cream color and not crowded in the pods. This is an intermediate variety between the black-eyed and Crowder Cowpeas.
- White acre Cowpeas —these Cowpeas are in kidney-shaped with a blunt end, these are semi crowded in the pod and are tan in color. These Cowpea pods are stiff with small seeds.
- Clay Cowpeas — these older variety Cowpeas and are in a dark brown in color and with kidney shape, this variety of Cowpeas grow rarely.
Read: Spirulina Farming.
Climate / Temperature for Growing Cowpeas:
- Cowpeas grow well in Summer season.
- The ideal temperature for germination is 5 to 8°C and for leaf growth 20°C.
- Cowpea plants are heat-resistant and drought-resistant crops.
- The optimum temperature for growth and seed productions is around 30°C.
- Temperature requirement is based on varieties and their response to day length, some varieties are insensitive and flowering within 30 days after sowing when grown at a temperature around 30°C.
- The time of flowering depends on the time and the location of sowing and may be more than 100 days. Even in early flowering varieties, the flowering period can more depend on warm and moist conditions, leading to asynchronous maturity.
- The optimum sowing times are December to January. Early-sown crops, tend to have elongated internodes are less erect, more vegetative and have a lower yield than those sown at the optimum time.
- The presence of nodular bacteria specific to Cowpea make it suitable for cultivation in the hot, marginal cropping areas of Southern Africa, as well as in the cooler, higher rainfall areas. However, Cowpeas are much less tolerant to cold soils. Cowpeas crop does best in summer season.
Water Requirements for Growing Cowpeas:
- Cowpea plants are highly drought-tolerant crop than many other crops. It can be grown as a rain-fed crop under a rainfall, ranging from 400 to 700 mm per annum.
- Cowpeas plants can even tolerate to water-logging. Well-distributed rainfall is important for normal growth and development of Cowpeas.
- The frequency and unreliability of rainfall can create problems in the growth of pods.
- In the areas with, high rainfall can result in flooding, while in some other areas, it is so unreliable that moisture conservation remains vitally important for crop production.
- Cowpeas plants are capable to utilize soil moisture efficiently and are more drought-more tolerant than groundnuts, soya-beans and sunflowers.
- Cowpeas grow well in areas with rainfall between 400 and750 mm. In some areas with high rainfall Cowpeascould be planted in peak period of rainfall during the vegetative phase or flowering stage so that the pod-drying could take place during dry weather.
- Cowpea crop needs an adequate rainfall during the flowering/podding stage.
- Cowpeas cannot tolerate moisture stress which causes improper growth of pods.
- Stress due to moisture can cause Flower and pod abscission and also serves as a growth-restricting mechanism.
Soil Requirements for Growing Cowpeas:
- Cowpeas grow in a wide range of soils.
- Sandy soils are highly preferred as they are less restrictive on root growth.
- Cowpea crops can tolerate infertile and acid soils.
- Lighter soil that is drought tolerant can reduce the leaf growth and reduces water loss through stomata, and leaf movement to reduce light and heat load under stress.
- Cowpeas are much less tolerant to cold soils which have a poor tolerance to waterlogging. Cowpeas thrive in well-drained soil and less on heavy soils.
- The pH levels of the soil growing Cowpeas should range from 5 to 6.
Method of Propagation for Growing Cowpeas:
Best technique for propagating Cowpeas are directly grown from seed.
Soil Preparation for Growing Cowpeas:
- The soil you select for growing Cowpeas should be well-drained but not be waterlogged.
- For preparing soil, the land be should plow thoroughly to remove weeds, trees and shrubs. You can do it manually or slashed with a tractor and fallen trees should be removed.
- And then harrowing, using a disc plough and the harrow.
- Each operation should be given 4 to 6 day gap, which helps to enhance good soil tilth for good seed germination. The land should be ridged or left as flat seedbeds after harrowing.
Field Layout and Design for Growing Cowpeas:
- The spacing between inter-row and intra-row spacing will be determined by a variety of Cowpea grown and their growing pattern.
- Each plant should be given enough space between plant and rows for trailing types to the upright growing pattern.
- For a profitable grain production, the number of plants should 200 000 to 300 000/ha at 30 to 50 cm inter-row spacing is preferred to wider rows (70 to 100 cm), this can be the perfect number of the trailing types.
Planting Tips for Growing Cowpeas:
- For the best yields, Cowpeas should be planted late November to early December in low rainfall areas. The seed should be planted at 3 to 4 cm deep in the soil.
- The early-sown Cowpeas have an elongated internode, are less erect, more vegetative and lower yielding than those sown at the optimum time.
- Date of planting can be manipulated by farmer due to many reasons. The reasons can be periods of high pest load or to plant Cowpea at such a time that harvesting of the crop would coincide with the period of dry weather.
Fertilization tips for Growing Cowpeas:
- Fertilizer application in Cowpea crops depends on anticipated yield and soil fertility.
- Cowpea fixes its own nitrogen and does not need nitrogen-based fertilizer.
- Seed should be inoculated with the appropriate Rhizobium species for optimum nitrogen fixation.
- Phosphate based fertilizer is highly recommended.
- Cowpea can grow in a soil pH range of 5.6 to 6.0.
- Enhancing the lands with organic manures is highly recommended.
Irrigation tips for Growing Cowpeas:
Cowpeas are usually grown under dry land rather than irrigated conditions.
Weed Control Tips for Growing Cowpeas:
- Annual grasses and some broadleaf weeds can be controlled by a pre-sowing application of herbicide.
- Row crop cultivation is best recommended method cultivation for Cowpeas, depending on the weed pressure, soil conditions, and rainfall. Pre-plant tillage can help you reduce early weed pressure, and the use of cover crops.
- Striga gesnerioides and Alectraspp are the most common weeds that attack Cowpeas, particularly in the semiarid regions. The following three are the most common Striga species that are a pest to Cowpea: S. hermonthica, S. asiatica and S. gesnerioides.
- Control of Striga weeds is difficult and time consuming. Using chemicals for controlling is not recommended, as the chemicals are expensive, handling them is very difficult and no research results are available to support chemical treatment.
- Farmers are advised to improve soil fertility to control the problems of weeds. Soil fertility influences Striga infestation; more fertile soils are less infested with Striga.
- Use of manure and less quality of fertilizers can reduce the infestation, when combined with the weeding of plants before seed setting.
- Hand weeding should be done before Striga sets seeds, it is the best method to control. Striga should be controlled before flowering, as the development of seeds takes only a few weeks. It may be necessary to weed the area twice in a season.
Pest Control for Growing Cowpeas:
- Cowpea crops are very attractive to pests. Pests are major setbacks for Cowpea production. At each stage, the attack of pests is very high.
- The main pests during the growing season are pod sucking bugs (Riptortusspp., Nezaraviridula and Acantomia sp.), aphis (Aphis fabae, Aphis craccivora), blister beetle (Mylabris spp.) and pod borer (Marucavitrata).
- Pests can be controlled by one or two applications of insecticide. For commercial production this will lead to downgrading of grain.
Aphid control tips for Growing Cowpeas:
- It is not necessary to control aphids, we should take necessary steps in case of large infestations are threatening the crop or when viral infections have been observed.
- Treatment for aphids is based mainly on visual counts and the stage of crop development. Measurable thresholds are not available. Several commercial pesticides are available in the market to control aphids. Heavy rains can reduce the number of aphids, for example the black Cowpea aphid, which are exposed on the pods.
- Frequently, parasites and predators prevent the infestation from becoming established throughout a field. Hot temperatures (higher than 30°C) frequently inhibit build-up of large densities of aphids.
- Plants that are seriously affected should be pulled up and burnt or fed to livestock. Harvested old plants should be removed from the field, as these often hosts the aphids.
- It is the oldest and best method to mix the Cowpea grains with ash. This method is safe and a cheap and best control method. For a best results, mix the grains with at least 5 % of ash.
- Don’t use chemicals in stored food. If chemical control is necessary, take technical assistance is for using them.
- Blister beetle (Mylabristincta) Farmers get worried, however, in the rare cases when large numbers of beetles are found on flowering crops. Beetles should be handpicked, Handpicking of beetles is not frequent as some species are known to give blisters. To speed up handpicking, a basic homemade net is recommended for catching the flying beetles.
Diseases Control Methods of Cowpeas:
- The most important disease that affects Cowpea plants is stem rot which is affected due to Phytophthora vignae.This disease mainly affects to Cowpea crops cultivated in wet coastal and subcoastal areas, and on heavier soils which may become waterlogged.
- Bacterial blight (Xanthomonas vignicola) is a bacterial disease that causes severe damage to Cowpeas.
- Another most frequent virus disease encountered is aphid-borne mosaic virus (CabMV).
- Some other major diseases that affect Cowpea plants are Fusarium wilt, bacterial canker, Cercospora leaf spot, rust and powdery mildew.
- Cowpea crops are also susceptible to nematodes and should therefore not be planted consecutively on the same land.
Birds, especially of the parrot family, could be a problem for Cowpea crops, as they can pull-up emerging seedlings and feed on developing green pods.
Harvesting of Cowpeas:
- Cowpeas vary in growth habit from an erect or semi-erect types with short (<100 days) growth duration, grown mostly for grain, to longer (>120 days) duration in semi- trailing plants which are normally grown primarily for forage.
- Once the pods start to mature, leaves will dry down, but may not drop off completely. They need to be harvested when seed moisture content is 14 to 18 %, depending on your requirement.
- In Cowpeas are grown for vegetable purposes, the leaves are picked 4 weeks after planting, and this continues until the plants start to flower.
- The Cowpea can be harvested using a harvester or by hand. The upright variety Cowpea seed plants are harvested by a machine.
- Cowpea grown as a dried seed and can be directly combined, using a platform head or a row crop head. Adjustments to combine settings and possibly sieve sizes should be made of the Cowpea seed.
- When the pods of Cowpea mature completely they become very long, some will touch the ground or be close to it, this shows a sign to run the grain table close to the ground.
- If growing Cowpeas for vegetable purposes, young leaves are mainly picked by hand. Harvesting of Cowpea should be done at the onset of the dry season when the dry pods can stay about a week awaiting harvesting without spoilage.
- To keep pods away from shattering and feathering, dry pods should not be left in the field longer than 2 weeks after full pod maturity.
Sorting: The quality of seed is very important. So good care should be taken in harvest and post-harvest actions to avoid cracking or split seed. Sorting is mainly done to separate the broken seeds from the full seeds.
Grading: Usually the young leaves or tender shoots in the distinctive color phase of new growth is gathered. Tender young leaves are rich in protein, and are insect resistant, often look more appealing. Older leaves accumulate dust or get spattered with mud from raindrops, while younger leaves would not need so much washing.
Packing: seeds should be cleaned and bagged. Packaged in sacks and put into electrical dryers or spread on a concrete slab in the case of sun drying to reduce the moisture content to about 12 %.
- Insect pests can trouble the Cowpeas during storage. There are some storage insects that cause damage to the seed; it is therefore important to store seed in a protected area. Cowpea Weevil Callosobruchus is a serious insect pest the affect Cowpeas during storage.
- The storage life of Cowpea depends on its moisture content before storage. Lower moisture content in seeds will improve its storage capability. An exposure to: 18°Cfor 6 to 24 hours can reduce pest numbers by more than 99 %.
- The grain can be stored for a short term at around 12 % moisture or less, with 8 to 9% recommended for long-term
- Cowpea leaves are dried to store them for the dry season. Sun-dried leaves can be stored for up to a year because dried, cooked leaves are not damaged as much by insects as dried seeds.
Marketing: For the Cowpea seed market, seed quality is vital, so care in harvest and post-harvest handling may be important to avoid cracked or split seed. Cowpea leaves are sold in South Africa, Ghana, Mali, Benin, Cameroon, Ethiopia, Uganda, Kenya, Tanzania,and Malawi.
Read: Red Gram Cultivation.