Cow pea (Vigna unguiculata (L) Walp)
Cowpea is an annual herb with varying growth forms. It may be erect, trailing, climbing or bushy, usually indeterminate under favourable conditions. It is an important food legume, and its use as leafy vegetable is essential in many African countries. Its ability to withstand drought, short growing period and multi-purpose use make cowpea a very attractive alternative for farmers in marginal, drought-prone areas with low rainfall and less developed irrigation systems.
Cowpea is a higher drought-tolerant crop than many other crops. It can grow under rainfall ranging from 400 to 700 mm per annum. The plants have a great tolerance to waterlogging. Well-distributed rainfall is important for normal growth and development of cowpeas.
Cowpeas grow best in warm conditions. The base temperature for germination is 8.5 °C and for leaf growth 20 °C. The optimum temperature for growth and development is around 30 °C. The crop is not tolerant to cold soils.
Cowpeas are grown on a wide range of soils but the crop shows a preference for sandy soils, which tend to be less restrictive on root growth. It is more tolerant to infertile and acid soils than many other crops. Cowpea can grow in a pH range of 5.6 to 6.5.