Overview
Sphenostylis kerstingii Harms is a leguminous plant species that belongs to the Fabaceae family. The plant is native to West Africa and is widely distributed throughout the Savannah woodland regions of the continent.
Common Names
The plant is commonly known as "Kersting's groundnut" or "bat bean" in reference to its edible tuberous roots that resemble groundnuts and its leaf pods that resemble the wings and body of a bat.
Appearance
The Sphenostylis kerstingii Harms plant is a creeping vine that grows up to 60 cm tall. The plant's leaves are pinnate and have three leaflets with serrated edges. The plant's flowers are small and range in color from cream to pale yellow. The plant's fruits are flat, thin, and wing-shaped pods that contain one or two seeds that are round and black when mature. The plant's tuberous roots are small, round and have a reddish-brown skin.
Uses
Sphenostylis kerstingii Harms is an important food crop in West Africa. The plant's tuberous roots are a source of carbohydrates and protein, and they are consumed fresh or dried. The plant's young leaves are used as a vegetable in soups and stews. The plant's seeds are also edible, and they are consumed after roasting or boiling. Additionally, the plant is widely used in traditional medicine to treat various ailments such as diarrhea, fever, and snake bites.
Light Requirements
Sphenostylis kerstingii Harms does not have strict light requirements, but prefers to grow in areas that receive full sunlight or partial shade. The plant can tolerate some shade, but prolonged exposure to low light levels can lead to stunted growth.
Temperature Requirements
Sphenostylis kerstingii Harms is adapted to grow in tropical and subtropical regions. The plant can withstand temperatures ranging from 20 to 35 degrees Celsius. Temperatures below 15 degrees Celsius can cause damage to the plant, while temperatures above 40 degrees Celsius can lead to dehydration and leaf burn.
Soil Requirements
Sphenostylis kerstingii Harms prefers well-drained soils that are rich in organic matter. The plant can grow in a wide range of soils including sandy, loamy and clay soils. The ideal soil pH for the plant is between 6.0 and 7.5. The plant can also tolerate slightly acidic or alkaline soils, but extreme soil pH can affect the nutrient availability and absorption capacity of the plant.
Cultivation of Sphenostylis kerstingii Harms:
Sphenostylis kerstingii Harms is a warm-weather plant that requires well-drained soil with a pH of 5.6 to 6.5. It prefers full sunlight exposure and can withstand prolonged periods of drought. The plant needs ample space to grow, so it is advisable to plant it at least one meter apart from other plants.
The plant is propagated from seeds, which should be sown in the early spring, as soon as the soil has warmed up to about 20°C. The seeds are laid in rows with a depth of 2.5-5 cm, and the seeds should be spaced at least 10 to 15 cm apart. The seedlings should emerge within two weeks.
Watering Needs:
Sphenostylis kerstingii Harms has moderate water requirements. It needs about 25 to 50 cm of rainfall during its growing season. However, during the prolonged dry season, the plant may require supplemental irrigation to maintain proper growth. Adequate water supply ensures the development of fleshy tubers.
Fertilization:
The plant requires a sufficient supply of nutrients, particularly nitrogen, phosphorus, and potassium. Using 10-20 tonnes of well-rotted manure or compost per hectare is recommended for the initial planting. Supplemental fertilization should be carried out after the plant has balanced its vegetative growth and reproductive growth. A compound fertilizer containing 14-20% nitrogen, 14-20% phosphorus, and 14-20% potassium should be applied every eight weeks.
Pruning:
Pruning is not a necessity in growing Sphenostylis kerstingii Harms, but you can cut back the plant to about 5 cm after harvesting. Doing so ensures that the new growth occurs from the base, which helps keep the plant healthy. Any damaged or diseased parts of the plant should be removed to prevent the spread of infection.
Propagation methods for Sphenostylis kerstingii Harms
Sphenostylis kerstingii Harms is a leguminous plant that is propagated mainly by seed. It is a hardy plant that grows well in tropical and subtropical regions such as Nigeria, Ghana, and Cameroon.
Seed Propagation
Seeds of Sphenostylis kerstingii Harms can be harvested from mature pods when they turn brown and start to dry on the plant. The seeds should be cleaned and sorted to remove any damaged or diseased seeds.
The seeds can be sown directly into the soil at a depth of 2-3 cm and spaced 10-15 cm apart. The soil should be well-drained and fertile. The best time to sow the seeds is during the rainy season, when the soil is moist and temperatures are warm.
Germination of Sphenostylis kerstingii Harms seeds is quick and usually occurs within 5-7 days. The seedlings should be thinned to leave only the strongest plants. They should be watered regularly and weeded to prevent competition for nutrients and moisture.
Cutting Propagation
Sphenostylis kerstingii Harms can also be propagated by stem cuttings. This method is less common than seed propagation, but it can be used to produce new plants quickly and easily.
The stem cuttings should be taken from mature plants during the rainy season. They should be about 10 cm long and have 2-3 pairs of leaves. The bottom pair of leaves should be removed, and the cuttings should be dipped in rooting hormone to promote root growth.
The cuttings should be planted in a well-draining soil mixture and kept moist. Rooting usually occurs within 2-3 weeks, and the new plants can be transplanted to their final location once they are well-established.
Overall, the most common propagation method for Sphenostylis kerstingii Harms is seed propagation. However, cutting propagation can also be used to produce new plants quickly and easily.
Disease Management
One of the most common diseases that affect the Sphenostylis kerstingii plant is root rot, caused by fungi such as Fusarium and Phytophthora. It can be prevented by planting the seeds in well-drained soil and avoiding overwatering. If the plant is already infected, remove the affected plant and treat it with an appropriate fungicide.
Another disease that affects the plant is bacterial wilt, caused by the bacterium Ralstonia solanacearum. The bacteria can survive in the soil for many years, infecting the roots and causing the plant to wilt and die. To manage this disease, it is important to practice crop rotation and avoid planting the same species in the same soil. Infected plants must be removed and disposed of, and the soil must be treated with appropriate chemicals.
Pest Management
The Sphenostylis kerstingii plant may also be attacked by various pests, such as aphids, thrips, and mites. These insects feed on the plant's sap, causing stunted growth, yellowing leaves, and curling. To manage these pests, the plants can be sprayed with insecticides or treated with insecticidal soap. Introducing predator insects such as lady beetles and lacewings can also help control the pest population.
The plant can also be attacked by nematodes, tiny worm-like creatures that live in the soil and feed on the plant's roots. Infected plants may exhibit stunted growth and yellowing leaves. To manage this pest, it is important to rotate crops and avoid planting susceptible plants in the same soil for extended periods. Soil fumigation or application of biological control agents such as fungi and bacteria can also help manage nematode populations.
