Cowpea is the most important source of protein in West Africa (Singh et al. 2001). It is an important crop in the Sahel because cowpea is tolerant to drought and improves soil quality through nitrogen fixation (IITA 2006). In addition, the grain contains 25% protein and the haulms contain 10 to 14% protein. The value of the cowpea haulms (in dried matter) is 50% to 80% that of the grains. 

Certain varieties mostly produce grain, while others produce fodder, and others again are dual-purpose varieties – grain as well as fodder production. Grain producing varieties are often erected while fodder varieties are creeping. Grain producing varieties lose their leaves when they ripen.       

Cowpea is very sensitive to insect attacks particularly in the flowering period and it is difficult to cultivate it without using spray against the thrips (Magalurothrips sjostedti) and the pod borer (Maruca vitrata). In Northern Nigeria, the average yield of cowpea production is 411 kg/ha if no insecticide treatment is used, 737 kg with one application at flowering time and 904 kg/ha with two applications (Ajeigbe and Singh 2006). The cost-benefit value of an application is 16.3 and 12.3 for two or three applications respectively. It is therefore recommended to spray two to three times. If no spraying is done, the most highly resistant varieties such as the IT90K-277-2 must be chosen. This variety ripens in 71 days. 

Cowpea planted as a pure crop with high density often gives higher yield than millet in pure stand. However, insect attacks tend to increase when density is high. The cowpea is normally planted after the first weeding of millet. Cowpea planting is an additional operation for farmers and not all farmers have the necessary manpower to that end.

Although cowpea fixes nitrogen, it can benefit from better soil fertility. The microdose method is also useful in order to have a good start in cowpea farming (see chapter on microdose).

Information on:

Cowpea illnesses and insects:
http://tchad.ipm-info.org/guide/niebe.htm

Cowpea general:
http://www.iita.org/cms/details/cowpea_project_details.aspx?zoneid=63&articleid=269.

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