In Kenya, peanuts are referred to us groundnuts and locally called “Njugu Karanga” (Swahili). Groundnuts are mainly grown in western Kenya by small scale farmers both for food and sale. These areas have a tropical climate suitable for farming.
There are two main varieties of peanuts in Kenya namely:
- The runner type and
- The bunch type (Red Valencia).
Bunch varieties are small, tastier and a highly marketable variety. It matures in 60 – 75 days. The runner is the larger variety and is preferred because of the high yields, it matures in 90 – 100 days.
Groundnuts are a rich source of protein and edible oils and add nitrogen into the soil and can be grown in poor soils. They take a shorter time span in the farm and have a huge market in Kenya. The monounsaturated and polyunsaturated fats found in groundnuts keep the heart healthy. The high protein should be regularly incorporated in diet for children, vegetarians and protein deficient people. They also contain high concentrations of the antioxidant polyphenols that inhibit the growth of free radicals, keeping infection at bay.
Forms in which Groundnuts can be consumed:
The groundnuts can be consumed in the following forms:
- Groundnut is consumed Raw
- Groundnuts can be Roasted
- Groundnuts can Blanched
- Groundnuts can be made into Peanut Butter
- Groundnuts can be Crushed mixed with Traditional Dishes or cooked on its own as source
Benefits of Groundnuts
The benefits of groundnuts include the following:
• Groundnuts are an excellent source of oil for Cooking.
• Groundnut cake is commonly used as Animal Feed.
• Groundnuts are largely grown by family farmers as Staple Food.
• Groundnuts can be sold to Raise Income.
• Groundnuts provide a valuable source of Proteins, Energy, Fats and Minerals
Conditions for growth
Groundnuts grow well in warm areas, below 1500 meters above sea level with temperatures ranging 28-30 degrees census. Low temperatures affect their flowering and seed formation. They also need 500 to 600 mm of rainfall, well-distributed throughout the growing season. The crop can survive drought or reduced rain but yields will be low. Well-drained soils are needed although the crop can also grow well in clay soils.
Planting date is linked to rainfall distribution in the area and length of the crop season. Soil moisture must be sufficient to guarantee good germination. Seeds must not be sown immediately after heavy rains since they imbibe too much water, which causes rotting. This also results in excessive soil compaction, which may hinder germination. In general early sowing improves yields (significant delay in sowing can reduce yield by 50%) and seed quality.
Seeds should be sown at a depth of 5–6 cm. To ensure uniform sowing depth, germination and crop stand, it is suggested that a groove 5–6 cm in depth is made along the rows for planting and, once the seed has been planted at the right depth and spacing, the soil is pressed down to ensure good contact with the seeds, enabling them to extract moisture more effectively.
It is important to sow groundnut seed in rows and at the right spacing as this helps:
- To reduce the incidence of rosette disease
- ensures a more uniform pod maturity, better quality seed and
- Maximizes yield.
Planting groundnut plants closer together results in individual plants setting fewer pods, but over a short period of time. Overall, this will ensure that the pods will be of a similar age and stage of development and, therefore, make it easier to decide when to harvest. Wider spacing will produce fewer yields per hectare.
Large scale growing of groundnuts
Spacing depends on the growth habit and the variety. Small seeded Spanish types (bunch) are spaced at 30-45 cm between rows and 7.5-10 cm between plants. This gives an optimum plant population of 167,000 per hectare. The large-seeded Virginia types (runner) are spaced at 60 cm between rows and 10-15 cm between stations, giving an optimum plant population of 89,000 per hectare. Under irrigation, plant population can be as high as 250,000 plants/ha. This depends on variety characteristics, seed quality and planting density. With manual sowing, individual seeds are sown 3-5 cm deep.
A well planned, crop rotation system can ensure good yields of high quality. In order to reduce risk in the farming system, groundnuts should be grown in rotation with other crops such as maize.
To avoid buildup of pests and diseases, groundnut should not be grown continuously on the same land. A rotation of three years or longer usually reduces disease burden.
Pest and disease management
Groundnuts are susceptible to several infections and pests which reduce yield and quality.
Most attacks are fungal, viral or bacterial related. The most common disease includes rosette, early leaf spot, late leaf spot and rusts. Aphids, leafminer, thrips, termites and beetles are the ravaging pests.
Spraying with insecticides, timely cropping and harvesting, intercropping, field sanitation, planting resistant varieties and proper storage are recommended
The majority of insect pests that attack groundnut can be grouped as:
- soil inhabiting insects (e.g. termites, white grubs, earwigs, subterranean ants);
- foliage feeding insects (leaf miner, caterpillars, armyworm, bollworm);
- those that transmit viral diseases (thrips, aphids); and
- insects that damage flowers and growing parts (blister beetle). Of all these, termites, aphids, thrips and leaf miner are the most important.
Determining when to harvest groundnuts is important. Since they can be flowering even at harvest time, a farmer must scout his garden on a regular basis. Hand pulling is one of the most used and suitable forms in sandy and loam soils while ox-drawn ploughs or hoeing can be used when drought sets in at harvesting time.
Damage to pods should be avoided as this can lead to aflatoxin contamination. When pods are damaged, moulds will enter and produce aflatoxins. The situation becomes worse when drying takes place on bare ground. Inadequately dried pods are another source of aflatoxins.
Since aflatoxins are becoming a major healthy concern,commercial farmers are advised to measure moisture content.
Harvesting by hand only is more suitable for the bunch/erect groundnut varieties in sandy, loam soils which are well drained. When the soil is wet and heavy or very dry, it is much more difficult to pull up the whole plant without losing pods.
Hand lifting with a hoe or fork
By using a hoe during harvesting it is possible to lift plants out of heavy or dry soil with a reduced pod loss. Spreading/runners varieties can also be more easily lifted. Care should be taken not to damage the pods with the hoe as damage makes the pods susceptible to fungal attack. A hoe fork lessens the likelihood of such damage.
It is important to shake the plant after lifting to remove excess soil from the pods, particularly when the soil is wet or heavy. Soil stuck to the pods will lengthen drying times and produce better conditions for the development of unwanted fungal growth.