Cowpea, scientifically known as Vigna unguiculata, is a type of plant that is cultivated annually for its seeds and leaves. It is a leguminous crop, and its leftover parts can be used as animal feed. One of the remarkable features of cowpea is its ability to survive dry conditions and grow quickly. This makes it an attractive choice for farmers in areas with low rainfall and marginal land.
In addition to its value as a crop, cowpea plays an important role in crop rotation because it helps improve soil fertility. Furthermore, certain varieties of cowpea mature early, allowing for faster food production compared to other crops.
In Kenya, the major regions where cowpea is grown include Kitui, Kisii, Migori, Kakamega, Bungoma, Machakos, Makueni, Kwale, Kilifi, and Tharaka Nithi.
Cowpea offers several nutritional and health benefits:
1. It is a good source of dietary fiber, which can help alleviate digestive issues like diarrhea and constipation.
2. It contains high levels of vitamin B and riboflavin.
3. Cowpea is rich in magnesium and tryptophan, which have a calming effect on the body. Magnesium also aids in carbohydrate metabolism, helping to regulate sugar levels and manage conditions like diabetes.
4. It provides significant amounts of iron, which helps in the production of red blood cells and prevents anemia.
5. Cowpea is low in calories and cholesterol, making it beneficial for weight management.
6. It is rich in vitamin C, a powerful antioxidant that combats the harmful effects of free radicals, which can lead to cancer and other chronic diseases.
7. The presence of calcium and minerals like iron, manganese, and magnesium in cowpea contributes to improved bone health.
8. Cowpea contains lysine, which can prevent or reduce the occurrence of cold sores and speed up the healing process.
Altitude: The crop can be cultivated in areas ranging from sea level up to 2000 meters above sea level, depending on the specific variety.
Rainfall: Cowpeas have a relatively high tolerance for drought and can produce reasonable yields with an annual rainfall of 300-700mm. Excessive rainfall or prolonged dry periods can negatively affect yields. Too much rain during flowering can cause the flowers to drop, while dry weather during harvesting is ideal.
Temperature: Cowpeas thrive in warm conditions. The best temperature range for their growth is between 20-35°C. Extreme temperatures can hinder the growth and development of the crop.
Soils: Cowpeas can be grown in a wide range of soils. However, well-drained and fertile soils with a pH level of 5.5-6.5 are optimal for better production.
Varieties: In Kenya, there are several cowpea varieties cultivated, including:
- Katumani 80 (K80)
- KVU 27-1, 419
- Kunde 1
- MTW 63, 610
- Machakos 66 (M66)
- Kitui black eye
- Other local varieties
The choice of cowpea variety depends on the specific agro-ecological zone. For example, certain improved varieties like Katumani 80 and Kitui black eye are suitable for dry areas. When selecting a variety, factors such as maturity period, resistance to pests and diseases, and market preference (such as grain color) should also be considered.
To plant one acre of land, approximately 8-10 kilograms of cowpea seeds are needed.
The potential yield of cowpeas varies depending on the variety and the overall crop maintenance practices and ecological conditions. With proper care, the yield can range from 800 to 1800 kilograms per acre.
Cowpeas are directly grown from seeds. Depending on the purpose of production, they can be grown as a sole crop or intercropped with other crops like maize.
Land Preparation & Planting
Early land preparation is important to allow weeds to dry out and decompose before planting. If rain-fed, planting should be done at the beginning of the rainy season to avoid crop failure or reduced yield due to delayed sowing.
1. Spray weeds with CATAPULT® 480SL at a rate of 200 milliliters per 20 liters of water. This will control both broadleaf and grass weeds.
2. Plow and prepare the land to create a fine, smooth surface.
3. Mix the soil with manure and DAP (diammonium phosphate). For improved nutrient uptake and soil pH stabilization, mix 1 kilogram of HUMIPOWER® with 50 kilograms of DAP and/or 1 ton of manure.
4. Sow the seeds, spacing them 6 inches apart within rows and leaving 24 inches between rows. Plant the seeds at a depth of about 3-4 centimeters.
5. Cover the seeds with loose soil.
- Use certified seeds.
- Germination usually occurs within 4-10 days.
Weeds compete with cowpea plants for nutrients, moisture, space, and sunlight. It is important to keep the cowpea garden weed-free to minimize losses. However, minimize weeding during the flowering and fruiting stages to avoid disturbing the crop.
The application of fertilizers in cowpea production depends on soil fertility. It is recommended to conduct soil testing to determine nutrient levels.
During planting, apply DAP by thoroughly mixing it with the soil to promote root development. Other phosphatic fertilizers like TSP can also be used. A week after germination, spray the young plants with LAVENDER SUPER STARTER® at a rate of 20 milliliters per 20 liters of water, or GOLDCHANCE SUPER START® at a rate of 50 grams per 20 liters. These products promote early crop establishment and provide additional benefits.
For top dressing, CAN (Calcium Ammonium Nitrate) is preferred. Additionally, the crop can be sprayed with GOLDCHANCE SUPER GROWTH® or LAVENDER SUPER GROWTH & VEGETATIVE® to stimulate rapid vegetative growth. However, cowpeas do not require excessive nitrogen fertilizer because they can fix their own nitrogen from the air using nodules in their roots. Applying too much nitrogen can delay maturity, reduce seed yield, and inhibit nitrogen fixation.
As the crop begins to flower and develop pods, spraying it with GOLDCHANCE SUPER FLOWERS & FRUITS®, DIMIPHITE®, GOLDCHANCE MULTISUPER K®, or VITABOR GOLD® can promote the production of quality pods and prevent flower abortion.
- Mix all basal fertilizers with HUMIPOWER® at a rate of 1 kilogram per 50 kilograms of fertilizer.
- OPTIMIZER® is an organic bio-stimulant that can be applied at any growth phase to enhance plant growth and stress management.
Cowpeas can be intercropped with other crops such as maize or sorghum. As a leguminous plant, cowpeas help fix nitrogen in the soil, improving soil fertility and enhancing overall yields.
Maturity & Harvesting
Cowpeas can be harvested at different stages of maturity, including leaves, green snaps, green-mature, and dry. The time it takes for cowpeas to mature their seeds varies depending on the variety and climatic conditions, typically ranging from 60 to 120 days.
For vegetable purposes, leaves should be harvested while they are young and tender, usually starting 2-3 weeks after planting.
Green pods can be hand-picked when they are still tender, around 12-16 days after flowering.
Mature, dried pods should be harvested promptly to prevent infestation by weevils and deterioration in humid weather. If most of the pods are mature, the entire plants can be pulled.
After harvesting, allow the pods to dry for about 2-3 days. Thresh the dried pods to separate the seeds from the pods, and winnow the seeds to remove any remaining debris. Proper drying is important to reduce moisture content and prevent mold during storage.
The pods can be manually threshed by gently beating them with a stick. Care should be taken not to damage the seeds. Alternatively, the pods can be manually broken by fingers to remove the seeds if the quantity is small.
Sorting & Grading
Sorting should be done to remove defective, shriveled, and broken grains, as well as stones, waste, and infected seeds. Grading can be done based on factors like size, color, and overall grain quality.
Packaging & Storage
Dry cowpeas are typically stored in treated gunny bags or PICS bags to protect them from storage pests. It is advisable to incorporate insecticides like Actellic super to prevent damage by pests while in storage. Storage bags should be placed on pallets, not directly on the floor.
For small quantities of seeds, storage in wood ash can be effective. Thoroughly mix the ash with the seeds.
Dried cowpea leaves can also be stored in waterproof containers for later consumption, especially when fresh green vegetables are not readily available.
Major Pests & Diseases
- Aphids: Control aphids by spraying with KINGCODE ELITE®, PENTAGON®, or LEXUS®.
- Bugs: Control bugs by spraying with EMERALD®, LOYALTY®, or PRESENTO®.
- African bollworm: Control African bollworm by spraying with KINGCODE ELITE®, BACIGUARD®, or SINOPHATE®.
- Flower beetles: Control flower beetles by spraying with KINGCODE ELITE®, PRESENTO®, or SINOPHATE®.
- Pod borer: Control pod borers by spraying with BACIGUARD®, KINGCODE ELITE®, or SINOPHATE®.
- Root knot nematodes: Control root knot nematodes by drenching the soil with ALONZE® or incorporating HUMIPOWER® with basal fertilizer.
- Thrips: Control thrips by spraying with ALONZE®, PROFILE®, or DEFENDER®.
- Whiteflies: Control whiteflies by spraying with TAURUS®, LEXUS®, or PROFILE®.
- Bean flies: Control bean flies through seed dressing with SHIELD® and soil drenching with EMERALD® or PROFILE®.
- Damping off: Control damping off by drenching the soil with PYRAMID® and spraying the crop with GEARLOCK TURBO®.
- Anthracnose: Control anthracnose by spraying with RANSOM®, ABSOLUTE®, or DUCASSE®.
- Rust: Control rust by spraying with MILESTONE®, RANSOM®, or DUCASSE®.
- Powdery mildew: Control powdery mildew by spraying with RANSON®, DOMAIN®, or CHARIOT®.
- Cowpea mosaic: Control cowpea mosaic by controlling aphid vectors with LEXUS®, KINGCODE ELITE®, or PENTAGON®.
- Cercospora leaf spots: Control cercospora leaf spots by spraying with CHARIOT®, RANSOM®, or DUCASSE®.
- Use INTEGRA as a sticker, spreader, and penetrant when mixing foliar sprays for increased efficacy.
- Observe the post-harvest interval (PHI) and re-entry interval (REI) for all applied chemicals.
- CADILAC® can be used as a preventative fungicide against diseases like anthracnose and leaf spots.
- Harvesting can be done manually or with a combine harvester for large-scale production.