Overview
Vigna unguiculata (L.) Walp. var. ovata (E.Mey.) B.J.Pienaar, commonly known as cowpea or southern pea, is a legume plant that is native to Africa. It is a versatile crop that can be grown for different purposes such as food, animal feed, and soil improvement.
Appearance
The cowpea plant is a vine that can grow up to 6 feet tall. It has trifoliate leaves that are oval to elliptical in shape and about 1 to 4 inches long. The flowers are usually white or purplish and are followed by pods that are cylindrical or slightly curved. The seeds are small, kidney-shaped, and vary in color from cream, beige, or light brown to dark brown or black.
Uses
Cowpea is a staple food crop in many African, Asian, and Latin American countries. The young leaves and tender pods are used as a vegetable, while the mature seeds are boiled, roasted, or ground into flour to make porridge or flatbreads. The seeds can also be sprouted and used in salads or sandwiches. Cowpea is a nutritious food that is rich in protein, fiber, vitamins, and minerals.
Aside from its food use, cowpea is also a valuable fodder crop for livestock. The plants are highly palatable and nutritious, making them an ideal feed for cattle, sheep, and goats. The leaves and stems can also be used as a green manure to improve soil fertility and control weeds. Cowpea is a drought-tolerant crop that can grow in poor soils and has the ability to fix nitrogen, which makes it a useful crop in sustainable farming systems.
Furthermore, cowpea has medicinal properties that have been traditionally used in some African countries. The powdered seeds are used for the treatment of diabetes, hypertension, and malaria, and the leaves and roots are used as a remedy for stomach ache and diarrhea. The plant is also known for its insecticidal properties and is used as a natural pest control agent.
Light requirements
Vigna unguiculata var. ovata is a warm-season crop that thrives in full sunlight. It performs best in areas with a minimum daily light dose of 5-6 hours, although it can tolerate light shade in hotter climates. In colder regions, it may require longer exposure to sunlight to achieve optimal growth.
Temperature requirements
Vigna unguiculata var. ovata is a heat-loving plant that requires warm temperatures to grow successfully. The ideal temperature range for this plant is between 25°C - 35°C. The minimum temperature required for growth is 20°C, while temperatures below 16°C may hinder its growth. The crop cannot withstand frost, and in areas where frost occurs, it should be grown during the warmer months.
Soil requirements
Vigna unguiculata var. ovata grows best in well-drained soils with a pH range of 6.0 to 7.5. The soil should be rich in nutrients and organic matter to support optimal growth. The plant can tolerate a variety of soil types, including sandy, loamy, and clay soils. However, it may have difficulty growing in heavily compacted soils and soils with poor drainage. Adequate soil moisture is essential for optimal growth, and the crop should be irrigated regularly depending on the rainfall patterns in a particular region.
Cultivation methods
Vigna unguiculata (L.) Walp. var. ovata (E.Mey.) B.J.Pienaar, commonly known as Cowpea, is a warm-season crop that requires well-drained soil with a pH between 6.0 to 6.5. Soil should be prepared by loosening it to a depth of at least 20 cm and removing weeds and debris. Plant cowpea in full sun and space the seeds 5 cm deep and 15 cm apart in rows spaced 60 cm apart. In areas with short growing seasons, cowpea may be started indoors 3-4 weeks prior to planting outdoors.
Watering needs
Cowpea requires moderate watering, and it is essential to keep the soil moist but not waterlogged to prevent seed rot and seedling damping-off. During the growing season, provide cowpea with at least 1 inch of water per week, preferably early in the day to allow for evaporation and reduce the risk of fungal diseases. Cowpea has some drought tolerance and can survive dry spells, but water is necessary for optimal growth and yield.
Fertilization
Cowpea requires moderate fertilization to produce significant yields. A balanced 10-10-10 NPK fertilizer should be applied during planting, at a rate of 2-3 pounds per 100 square feet. Additional nitrogen-rich fertilizers, such as compost or manure, can be applied to the soil during the growing season to provide adequate nutrition. Cowpea has a symbiotic relationship with nitrogen-fixing bacteria, which can reduce the amount of nitrogen the plant requires from soil fertilizers. Cowpea also benefits from foliar fertilization, which enhances nutrient uptake and overall plant health.
Pruning
Cowpea is a bushy plant that does not require pruning. However, removing dead leaves and diseased plant parts can increase air circulation and reduce the incidence of fungal diseases. If the cowpea plant begins to outgrow its space, it can be pinched back to promote branching and reduce height.
Propagation of Vigna unguiculata (L.) Walp. var. ovata (E.Mey.) B.J.Pienaar
Vigna unguiculata (L.) Walp. var. ovata (E.Mey.) B.J.Pienaar, also known as Bambara groundnut, can be propagated both sexually and asexually. The plant is generally propagated through seeds, stem cuttings, and root cuttings. Each method has its own set of benefits, drawbacks, and requirements.
Sexual propagation
The most common method of propagating Vigna unguiculata var. ovata is through seeds. Seeds must be harvested when the pods are dry and mature. The pods are harvested when they turn brown or yellow and begin to dry out. The seeds can then be removed from the pods and sown immediately. The seeds can be sown directly into the soil or started indoors and then transplanted when they are big enough.
Asexual propagation
In addition to sexual propagation, Vigna unguiculata var. ovata can also be propagated asexually. This method involves taking stem cuttings or root cuttings. Stem cuttings should be taken from healthy, disease-free plants during the growing season. The cuttings should be about 10 cm long and should have a few leaves attached. The lower leaves should be removed, and the cutting should be planted in a suitable rooting medium such as sand or vermiculite. Root cuttings are taken during the dormant season and planted in the same way as stem cuttings.
Disease Management
Vigna unguiculata (L.) Walp. var. ovata (E.Mey.) B.J.Pienaar, commonly known as cowpea, is susceptible to various diseases that can significantly reduce its yield. Some of the most common diseases that affect the plant include:
- Anthracnose: This is a fungal disease that causes circular or irregularly shaped lesions on the leaves, stems, and pods of the plant. To manage anthracnose, it is essential to remove and destroy all infected plant parts and use fungicides to control the spread of the disease.
- Bacterial blight: This is a bacterial disease that causes water-soaked lesions on the leaves, stems, and pods of the plant. To manage bacterial blight, it is essential to remove and destroy all infected plant parts, use disease-free seeds, and avoid overhead irrigation that can spread the bacteria.
- Mosaic virus: This is a viral disease that causes mottled yellowing and curling of leaves, stunted growth, and reduced yield. To manage mosaic virus, it is essential to control the aphids that spread the virus, use disease-free seeds, and practice crop rotation.
- Fusarium wilt: This is a fungal disease that causes wilting and yellowing of leaves, stunted growth, and rotting of the roots. To manage fusarium wilt, it is essential to use disease-free seeds, practice crop rotation, and use fungicides to control the spread of the disease.
Pest Management
Cowpea is also vulnerable to attack by various pests that can cause significant damage to the plant. Some of the most common pests that affect the plant include:
- Aphids: These are tiny insects that suck sap from the leaves and stems of the plant, causing stunted growth and reduced yield. To manage aphids, it is essential to use insecticides, encourage natural predators like ladybugs and lacewings, and practice crop rotation.
- Thrips: These are small insects that feed on the leaves and flowers of the plant, causing stippling and distortion of leaves and flower buds. To manage thrips, it is essential to use insecticides and encourage natural predators like mites and beneficial insects.
- Cowpea curculio: This is a beetle that feeds on pods and causes scarring and distortion, leading to reduced yield. To manage cowpea curculio, it is essential to use insecticides and remove and destroy all infected pods.
- Leafhoppers: These are small insects that feed on the sap of the plant, causing yellowing and wilting of leaves and reduced yield. To manage leafhoppers, it is essential to use insecticides and encourage natural predators like spiders and praying mantises.
It is crucial to monitor the plant regularly for any signs of disease and pest infestation to promptly initiate management measures. Additionally, maintaining crop hygiene by removing and destroying infected plant parts and practicing crop rotation can help prevent the spread of diseases and pests.
