Cowpea
A hardy, nitrogen-fixing legume vital for semiarid regions.
The cowpea, or Vigna unguiculata, is an annual legume that can grow upright, trail along the ground, or climb. It shows wide variation in size, shape, and structure, with four subspecies, three of which are farmed. Its ability to thrive in sandy soil with little rain makes it vital in semiarid parts of Africa and Asia. Domesticated in Africa, it is one of the oldest cultivated crops, with a likely second domestication in Asia before spreading to Europe and the Americas.
Quick Facts
- Annual world production
- 3 million tonnes (1997 estimate)
Facts from the source article.
Lore & Background
Nigeria and Niger together grow two-thirds of the world's cowpeas, with most production happening across Africa. Back in 1997, estimates put the global crop at about 3 million tonnes grown on 12.5 million hectares, feeding around 200 million people daily. Bugs are a huge problem for cowpea farmers, sometimes wiping out over 90% of a harvest. The main pest before harvest is the legume pod borer, Maruca vitrata, while the cowpea weevil, Callosobruchus maculatus, does the most damage after harvest. The plant is easy to grow because its roots fix nitrogen from the air, so it needs little fertilizer, making it ideal for poor farmers and for planting alongside other crops. People mostly grow cowpeas for their protein-rich seeds, which get cooked into stews and curries or ground into flour or paste. The leaves and young pods are also edible. Farmers use the whole plant as animal feed, which is probably how it got the name "cowpea."
Reader's Guide
Cowpeas thrive in poor dry conditions, growing well in soils up to 85% sand. The optimum temperature for cowpea growth is 30°C, making it only available as a summer crop for most of the world. It grows best in regions with an annual rainfall between 400 and 700 mm. The ideal soils are sandy and it has better tolerance for infertile and acid soil than most other crops. Generally, 133,000 plants per hectare for the erect varieties and 60,000 per hectare for the climbing and trailing varieties. The seeds can be harvested after about 100 days or the whole plant used as forage after about 120 days. Leaves can be picked from 4 weeks after planting. These characteristics, along with its low fertilisation requirements, make the cowpea an ideal crop for resource-poor farmers living in the Sahel region of West Africa. Early-maturing varieties of the crop can thrive in the semiarid climate, where rainfall is often less than 500 mm. The timing of planting is crucial, as the plant must mature during the seasonal rains. The crop is mostly intercropped with pearl millet, and plants are selected that provide both food and fodder value instead of the more specialised varieties.
Did You Know?
- The cowpea is one of the oldest domesticated crops, with remains from Central Ghana dated to the 2nd millennium BC.
- Black-eyed peas are a common name for a cowpea cultivar, named for the distinctive black spot on the hilum.
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