Key points of high-yield cultivation techniques for cowpea: grow it this way for higher yields
Cowpea (Vigna unguiculata), also called yardlong bean, is a vegetable that is abundant in summer. It belongs to the cultivated species of the cowpea species that can form long pods, an annual twining herbaceous plant. Also known as cowpea, long-horn bean, string bean, and kidney bean. It contains various vitamins and minerals, etc. The young pods are thick and fleshy, crisp and tender when stir-fried, and can also be blanched for cold salads or pickled. The pods are long and tube-like, crisp in texture but soft in body, and there are commonly two types: white cowpea and green cowpea. When selecting cowpeas, it is generally best to choose those with uniformly thick pods, bright color, a translucent gloss, and plump seeds, while cowpeas with cracks, wrinkled skin, pods that are too thin with no seeds, or insect marks on the surface should not be purchased. Cowpea has excellent nutritional content and is the meat among vegetables.
Morphological characteristics of cowpea
Annual twining, herbaceous vine or nearly erect herb, sometimes twining at the tip. Stems nearly hairless. Pinnately compound leaves with 3 leaflets; stipules lanceolate, about 1 cm long, extended downward at the point of attachment into a short spur, with linear striations; leaflets ovate-rhombic, 5-15 cm long, 4-6 cm wide, apex acute, margin entire or nearly entire, sometimes pale purple, hairless. Racemes axillary, with long peduncles; 2-6 flowers clustered at the tip of the inflorescence, with fleshy glands often between the pedicels; calyx pale green, bell-shaped, 6-10 mm long, lobes lanceolate; corolla yellow-white with a slight greenish-purple tinge, about 2 cm long, each petal with a claw, standard petal oblate, about 2 cm wide, apex slightly concave, base slightly auriculate, wings slightly triangular, keel slightly curved; ovary linear, hairy. Pods pendulous, erect or spreading obliquely, linear, 7.5-70 (90) cm long, 6-10 mm wide, slightly fleshy and inflated or solid, with many seeds; seeds long elliptical or cylindrical or slightly kidney-shaped, 6-12 mm long, yellow-white, dark red or other colors. Flowering period May-August.
How to cultivate cowpea for high yield?
1. Sowing and seedling raising generally uses the direct seeding method. However, in early spring when temperatures are low, if conditions permit, the method of raising seedlings in greenhouses or small arched sheds and then transplanting can be used. About 8-10 days after sowing, when the first pair of true leaves unfolds, transplant in a timely manner. The seedbed can also be covered with plastic film after sowing to increase soil temperature.
2. Reasonable close planting: choose fields with higher terrain, good drainage, and neutral or slightly acidic loam or sandy loam for planting. When preparing the land, deep furrows and high beds should be made, and the bed soil should be deeply plowed and sun-bleached. In the Guangzhou area, the bed width (including furrow) is generally 1.5-1.8 m, with double-row planting, 2 seeds per hole, and a plant spacing of about 15 cm. It can also be intercropped with leafy vegetables, using single-row planting, with vegetables such as choy sum and Chinese cabbage intercropped along the bed edges.
3. Reasonable fertilization: attention should be paid to applying sufficient base fertilizer. Generally, apply 1000-1500 kg of organic fertilizer, 50 kg of superphosphate, and 20-30 kg of potassium sulfate per mu. During the seedling stage, 1-2 applications of dilute human manure water, etc. can be applied. During the flowering and podding stage, heavy topdressing should be applied in a timely manner to prevent premature senescence, with 20 kg of compound fertilizer applied per mu, and then topdressing once every 7-10 days thereafter. When necessary, foliar topdressing should be carried out to reduce flower and pod drop. After the peak podding stage, fertilizer and water management should continue to be strengthened to promote the plants“reflowering”, extend the harvest period, and increase cowpea yield.
4. Field management.
1. Inserting bamboo poles and training vines: generally, when the seedlings grow to 30-40 cm, insert bamboo poles and train the vines. Vine training should be carried out in clear weather when the climate is cool, and it is appropriate to train about 4 vines per bamboo pole.
2. Fertilizer and water management: cowpea fertilization should be based mainly on base fertilizer, supplemented by topdressing. For the base fertilizer, when making the beds, apply 1500-2000 kg of high-quality farmyard manure and 20 kg of compound fertilizer, and at the early flowering stage, when earthing up, apply 30-40 kg of Xingwang fruit and vegetable compound fertilizer on both sides of the bed. Topdressing during the seedling stage should be light and dilute, and the fertilization concentration should gradually increase as the plants grow. Each topdressing should be carried out on a sunny day. During the harvest period, apply supplementary topdressing as appropriate according to the growth condition.
Cowpea dislikes moisture throughout its entire growth period. Excessive soil moisture can easily cause excessive vegetative growth or root rot. This is especially true when the soil is too wet after sowing, as the seeds absorb too much water and germinate too early and too quickly, making the seedling tissues delicate, weakening stress resistance, and easily causing excessive vegetative growth or seedling death. Therefore, sowing should be carried out on a sunny day, and before sowing, the sowing rows should first be watered thoroughly and then sown, and no watering should be done within 2-3 days after sowing. When the seeds begin to emerge, water appropriately, which is beneficial for strong seedling growth. During flowering and podding, the water requirement is relatively large. Especially in autumn, when temperatures are high and water evaporation is large, watering should be done in the morning and evening to regulate the field microclimate.
4. Pest and disease control.
The main cowpea diseases are root rot and rust. Root rot should follow the principle of“prevention first, combining prevention and control” through crop rotation and field management. At the same time, when sowing, mix 1 kg of 50% carbendazim with 400-500 kg of fine soil and cover the seeds. In the early stage of the disease, drench the roots with 200-300 times dilution of 37% root rot spirit or 1000-1500 times dilution of dexon, once every 3-5 days, for 2-3 consecutive applications. For rust, spray with 200-250 times dilution of colloidal sulfur or 150-200 g of 15% triadimefon wettable powder mixed with 75-80 kg of water. The main insect pests are the bean pod borer and the cowpea pod borer. From the bud stage to the early flowering stage, spray once every 7-10 days with 500 times dilution of 25% dimehypo aqueous solution or 50-75 g of cascade mixed with 60 kg of water, for 2-3 consecutive sprays.