What are the key cultivation techniques for increasing cowpea yield?

Cowpea (scientific name Vigna unguiculata), commonly known as yardlong bean, ginger bean, banded bean, hanging bean pod. Cowpea is divided into two types: long cowpea and rice cowpea, belonging to the legume family. Cowpea is an annual plant of the legume family. The stem has three types: dwarf, semi-climbing and climbing. In the south, climbing types are mainly cultivated, followed by dwarf types. It is an annual twining herbaceous plant of the Fabaceae (papilionaceous) family, with 3 leaflets; the terminal leaflet is rhombic-ovate, 5-13 cm long, 4-7 cm wide, acute at the apex, nearly rounded or broadly cuneate at the base, hairless on both sides; the lateral leaflets are obliquely ovate; the stipules are ovate, about 1 cm long, extending downward at the point of attachment into a short spur. The calyx is bell-shaped, hairless; the corolla is pale purple, about 2 cm long, with pale yellow hairs on the upper inner side of the style. The pod is linear, drooping, up to 40 cm long. The flowering and fruiting period is June to September.

Growth habits of cowpea

Cowpea requires high temperatures and has strong heat tolerance. The optimum growth temperature is 20-25°C. It can still set pods normally at high temperatures above 35°C in summer without dropping flowers, but it is not tolerant of frost. Under prolonged low temperatures below 10°C, growth is inhibited. Cowpea is a short-day crop, but long cowpeas cultivated as vegetables mostly belong to the intermediate photoperiod type and are not very strict about sunlight requirements. For example, varieties such as Hongzuiyan and Zhijiang 28-2 can be cultivated in spring, summer and autumn in the south. Cowpea has wide adaptability to soil; as long as the field has good drainage and loose soil, it can be planted. The pods are tender, and sufficient fertilizer and water are required during the pod-setting period. Cowpea is a climbing plant, so when the seedlings grow to more than 30 cm, a trellis about 2 m high should be set up in time. The materials are usually reeds, thin bamboo poles, thin wooden sticks, etc. The tips of its branches have a twining and climbing habit and will climb upward on their own.

How can cowpea increase yield?

Cowpea is a commonly used vegetable. With the development of the vegetable processing industry, cowpea, like some other vegetables, is increasingly in short supply. To increase cowpea yield and improve cowpea quality, the following three key technical measures need to be grasped:

1. Selecting good varieties

In early spring and late autumn, when surface temperatures are low and sunshine is short, cold-tolerant early-maturing varieties should be selected. Better-performing varieties include Yangjiang 12, etc. For summer sowing, due to high temperatures and long sunshine, heat-tolerant varieties should be selected. Better-performing varieties include Yangjiang 40, etc.

2. Formula fertilization

Cowpea is a vining plant with a relatively long vegetative and reproductive growth period, so attention should be paid to the skillful application of base fertilizer and foliar fertilizer. In the base fertilizer, appropriately increase the proportion of phosphorus and potassium fertilizers and reduce the proportion of nitrogen fertilizer to prevent excessive vegetative growth in the later stage and a short flowering period, which would affect cowpea yield; in the later stage, combined with pest and disease control, appropriately increase the supplementary application of foliar fertilizer to extend the cowpea growth period.

3. Field management

Vigorously control pests and diseases. Cowpea is afraid of waterlogging; clearing ditches and draining water can both promote robust cowpea growth and improve cowpea disease resistance. Every year in July and August is the period when cowpea pests and diseases are prone to occur. The main pests and diseases include downy mildew, rust, aphids, cabbage caterpillars, etc. The control methods are: for diseases, spray with fungicides such as flumorph mancozeb and triadimefon; for insect pests, spray with insecticides such as Kaiwei 168 and abamectin. Note that when spraying insecticides, it is necessary to choose 8 or 9 a.m. and soak the flowers, young pods and vines thoroughly for it to be effective. To delay premature senescence, 200 g per mu of monopotassium phosphate can be added to the spray liquid, thereby increasing yield.