Cowpea Farming and Management
Cowpea is one of the crops which is grown in dry lands of different countries. It is an ideal dryland crop (pulse) in low rainfall areas because it is a drought resistant and provide excellent human nutrition and good rotational benefits. Cowpea can also be intercropped with maize.
Key facts of Cowpeas
- It is grown as pure stand or intercropped with Maize and Sorghum.
- It’s drought tolerant, performs well in a wide variety of soil types, and being a legume, replenishes low fertility soils when the roots are left to decay.
- Grown both as a leafy vegetable and for its grain
- Plant types can be classified as erect, semi- erect or trailing types.
- Rich in calcium, iron, zinc, and vitamin B complex.
Varieties and Cultivars
You should select a variety that is suited to your agroecological zone, based on its suitability for the prevalent climatic conditions and cropping systems. The choice of Cowpeas variety is based on maturity period, yield potential, drought tolerance, responsiveness to day-length, parasitic weed infestation, and pest and disease resistance.
There are two basic types of cowpeas: upright, bunch types, which is used mainly for grain production; and spreading types, which is used for grain, vegetable or fodder.
Climatic Requirements
Temperature
Cowpeas grow best during summer. It requires a germination temperature of 8.5°C and for leaf growth 20°C. It is a heat-loving and drought-tolerant crop. The optimum temperature for growth and development of Cowpeas, is around 30°C.
Water
Cowpea is a drought-tolerant crop, which can grow in low rainfall zone. It can grow under rainfall in areas which receive annual rainfall ranging from 400 to 700 mm per annum.
Cowpeas are also tolerance to waterlogging. Well-distributed rainfall is important for normal growth and development of cowpeas. The frequency and unreliability of rainfall pose problems to cowpea growth.
As a drought tolerant plants, Cowpeas utilise soil moisture efficiently and are more drought-tolerant than groundnuts, soya-beans and sunflowers.
Soil requirements
Cowpeas perform better on a wide range of soils, but it grow best on the sandy soils, which tend to be less restrictive on root growth. It is more tolerant to infertile and acid soils than many other crops. This adaptation to lighter soils is coupled with drought tolerance through reduced leaf growth, less water loss through stomata, and leaf movement to reduce light and heat load under stress during its growing stages.
Cowpeas are much less tolerant to cold soils than common beans and show a poor tolerance to waterlogging, as they are considered drought tolerant plants. They thrive in well-drained soil and less on heavy soils.
They requires an optimum soil pH of between 5,6 and 6,0. When selecting your site, consider the soil requirements discussed.
Cultivation Practices
1. Site selection
Proper site selection is very important. You should select a well-drained sandy loam soil for rainfed cowpea, and inland depressions or along the shores of a lake for a dry season Cowpeas crop using residual moisture. Cowpea does not tolerate excessively wet conditions or waterlogging and should not be grown on poorly drained soil.
2. Propagation
Cowpea is directly grown from seed.
3. Soil preparation
Having selected the site where you will grow your Cowpeas, the next step is to clear the site of shrubs and stubble.
The selected site should be prepared manually with the hand-hoe. Soils should be cultivated deeply enough to ensure that no barrier exists to penetration of the soil by the taproot. If using a tractor, plow and harrow the Cowpeas field to provide sufficient tilth for good root growth.
Well prepared site ensures good germination and reduces weed infestation. You should make ridges thereafter, if desired. Where the soils are more fragile and prone to erosion in your selected site, adopt minimum or zero tillage. The selected site should not be waterlogged but well drained.
4. Field layout and design
Both interrow and intrarow spacing will be determined by the type of variety and growing pattern. You should achieve a plant population of 200 000 to 300 000/ha at 30 to 50 cm interrow spacing.
5. Planting
You should plant your Cowpeas anytime from the first rains. In high rainfall regions, you should plant your Cowpeas late to avoid diseases when the crop reaches maturity.
6. Fertilisation
Cowpeas respond well to manure or low rates (100 to 200 kg per ha) of a compound fertiliser. Fertiliser application in cowpea production depends on anticipated yield and soil fertility. Before any application of fertilizer, you should conduct a soil test.
As a legume, cowpea fixes its own nitrogen, and does not need nitrogen fertiliser. Cowpeas Seed should be inoculated with the appropriate Rhizobium species for optimum nitrogen fixation.
7. Irrigation
Cowpeas are usually grown under dryland rather than irrigated conditions, this is why they are considered drought tolerant plants.
8. Weed Control
Annual grasses and some broadleaf weeds should be controlled by a pre-sowing application of herbicide. You can also eliminate weeds by hoeing or cultural methods.
9. Harvesting
Cowpeas harvesting can be carried out manually (hand harvesting) or by using a combine harvester in the case of large-scale production. You harvest when the pods are dry in a sunny day. To avoid field weathering or shattering, dry pods should not be left in the field longer than 2 weeks after full pod maturity.