page_title: Cowpea
section_title: Cultivation
hierarchical_section_title: Cowpea / Cultivation
caption_attribution_description: African farmers domesticated the cowpea (Vigna unguiculata) from its wild form, in a process of inconscious selection over many centuries. Domesticated cowpea has much larger seeds that have lost its dormancy of the wild progenitor.
context_page_description: The cowpea is an annual herbaceous legume from the genus Vigna. Due to its tolerance for sandy soil and low rainfall, it is an important crop in the semiarid regions across Africa and Asia. It requires very few inputs, as the plant's root nodules are able to fix atmospheric nitrogen, making it a valuable crop for resource-poor farmers and well-suited to intercropping with other crops. The whole plant is used as forage for animals, with its use as cattle feed likely responsible for its name.
  Four subspecies of cowpeas are recognised, of which three are cultivated. A high level of morphological diversity is found within the species with large variations in the size, shape, and structure of the plant. Cowpeas can be erect, semierect, or climbing. The crop is mainly grown for its seeds, which are high in protein, although the leaves and immature seed pods can also be consumed.
  Cowpeas were domesticated in Africa and are one of the oldest crops to be farmed. A second domestication event probably occurred in Asia, before they spread into Europe and the Americas. The seeds are usually cooked and made into stews and curries, or ground into flour or paste.
context_section_description: Cowpeas thrive in poor dry conditions, growing well in soils up to 85% sand. This makes them a particularly important crop in arid, semidesert regions where not many other crops will grow. As well as an important source of food for humans in poor, arid regions, the crop can also be used as feed for livestock. Its nitrogen-fixing ability means that as well as functioning as a sole crop, the cowpea can be effectively intercropped with sorghum, millet, maize, cassava, or cotton.
  The optimum temperature for cowpea growth is 30 °C (86 °F), 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 (16 and 28 in). The ideal soils are sandy and it has better tolerance for infertile and acid soil than most other crops. Generally, 133,000 seeds are planted per hectare (54,000/acre) for the erect varieties and 60,000 per hectare (24,000/acre) 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 (20 in). 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.
  Storage of the seeds can be problematic in Africa due to potential infestation by postharvest pests. Traditional methods of protecting stored grain include using the insecticidal properties of Neem extracts, mixing the grain with ash or sand, using vegetable oils, combining ash and oil into a soap solution or treating the cowpea pods with smoke or heat. More modern methods include storage in airtight containers, using gamma irradiation, or heating or freezing the seeds. Temperatures of 60 °C (140 °F) kill the weevil larvae, leading to a recent push to develop cheap forms of solar heating that can be used to treat stored grain. One of the more recent developments is the use a cheap, reusable double-bagging system (called PICs) that asphyxiates the cowpea weevils.
caption: Seeds from the wild-type cowpea are much smaller than the cultivated varieties
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