Cowpea

Cowpea is a multipurpose legume grown for its dry seed, its tender green pods and leaves used as vegetables, and its haulms fed to livestock. Growth habit ranges from erect determinate types suited to grain production to spreading, indeterminate types used for fodder and ground cover.

Its short growing cycle and drought tolerance make it well suited to rain-fed cropping in the dry tropics, where it is commonly intercropped with cereals such as sorghum, millet, and maize.

Family

Fabaceae (legume family)

Genus and species

Vigna unguiculata

Growth habit

Annual herb ranging from erect to prostrate and climbing, bearing trifoliate leaves and long pods

Root system

Taproot bearing nodules that host nitrogen-fixing rhizobia

Cowpea is widely regarded as having been domesticated in Africa, where the greatest diversity of the crop and its wild relatives occurs, before spreading to Asia and, later, to the Americas. Sub-Saharan Africa remains the center of production and consumption.

Statistics on planted area, production, and trade by country are compiled by FAO and national agencies and should be consulted directly for current figures.

Cowpea is a warm-season crop requiring high temperatures for good growth and is sensitive to frost and cool conditions. It is among the more heat- and drought-tolerant grain legumes, completing its cycle rapidly and escaping late-season drought in short-season environments.

Excessive humidity and rainfall during flowering and pod fill can favor foliar disease and reduce grain quality, so the crop is often best adapted to warm, relatively dry growing seasons.

Cowpea grows on a wide range of soils and is notably productive on light, sandy soils of low fertility where many other crops perform poorly. Good drainage is important, as the crop is sensitive to waterlogging.

Cowpea is direct-seeded once soils are warm, either as a sole crop or intercropped with cereals. Growth habit is chosen to match the objective, with erect types favored for grain and spreading types for fodder and soil cover.

• Cultivar and growth habit matched to end use (grain, vegetable, or fodder)
• Intercropping with cereals in many smallholder dry-tropics systems
• Timely weed control during early establishment, when cowpea competes poorly
• Rhizobial inoculation in fields where effective nodulation is uncertain

Effective nodulation allows biological nitrogen fixation to meet much of the crop’s nitrogen demand. Phosphorus is frequently limiting on the sandy, weathered soils where cowpea is grown, and phosphorus supply is often key to good nodulation and yield.

Cowpea is grown mainly under rain-fed conditions, where its short cycle and drought tolerance allow it to produce a crop in seasons too dry or short for many alternatives. Supplemental irrigation is used in some systems, especially for vegetable-type production.

Moisture during flowering and pod fill supports yield, while the crop’s ability to mature quickly helps it avoid terminal drought in marginal environments.

Insect pests are the leading constraint to cowpea production. Legume pod borers attack flowers and developing pods, aphids feed on foliage and transmit viruses, and flower thrips damage the reproductive structures. Storage weevils cause serious losses in dry seed after harvest.

Anthracnose and root rots are among the fungal diseases affecting the crop, particularly under humid conditions and poor drainage. Management combines resistant cultivars, field sanitation, monitoring, and, where warranted, locally authorized controls applied according to their labels.

Dry cowpea is harvested once pods have matured and dried; because pods often mature unevenly, hand picking in several passes is common in smallholder systems, while uniform determinate types can be machine harvested. Green pods and leaves are picked at a tender stage for fresh use.

• Dry seed used in a wide range of dishes and as a protein staple across Africa, Asia, and the Americas
• Tender green pods and leaves eaten as vegetables
• Haulms and residues fed to livestock as high-quality fodder
• Use as a cover crop and green manure to improve soil fertility