Origin
Sphenostylis erecta (Baker f.) Hutch. ex Baker f. subsp. erecta, also known as the African Yam Bean, is a plant species native to tropical Africa. It is widely cultivated for its edible tubers and beans, which are a staple food in many parts of Africa. The Latin name "Sphenostylis erecta" means "erect wedge-shaped style", referring to the shape of the style of the plant's flowers.
Common Names
The African Yam Bean is known by many common names, including jicama de Angola, Bengana, yam bean, and jigbo. In Nigeria, it is called "okpodudu" or "okpodote" in Edo language, and "Akidi" or "Ewa" in Igbo and Yoruba languages respectively.
Uses
The tubers of Sphenostylis erecta are rich in protein and are important in traditional African diets as a source of carbohydrates and nutrients. In addition to food, the plant has various medicinal uses, such as treating stomach ailments and snake bites. The leaves of the plant are also used as animal feed and fertilizer. The plant's tubers and beans are also being studied as potential sources of biomass for biofuel production.
General Appearance
Sphenostylis erecta is a climbing or trailing vine that can grow up to 3 meters long. Its leaves are trifoliate (with three leaflets) and can be up to 18 cm long. The flowers are small and white or pink, and the plant bears elongated seed pods that can be up to 15 cm long. The plant's tubers are typically round or oblong and can be up to 10 cm in diameter. The beans are also elongated and can be up to 4 cm long.
Light Requirements
Sphenostylis erecta requires full sunlight for optimal growth. It is not shade-tolerant and will not thrive in shaded areas. The plant may also struggle in areas with too much direct sunlight, for example, under a greenhouse or glasshouse with no shading. Therefore, Sphenostylis erecta grows best in open fields or bright locations with plenty of light.
Temperature Requirements
Sphenostylis erecta grows in tropical and subtropical regions in Africa and South America. The plant can tolerate high temperatures of up to 35°C and low temperatures of 10-15°C. However, the ideal temperature range for the plant's development is between 20-30°C. The growth rate may be reduced or halted if temperatures are too extreme. Additionally, it is important to ensure that the plant is protected from frosts during the winter months if grown outside of its native range.
Soil Requirements
Sphenostylis erecta prefers well-drained, loamy soils with a pH range of 5.5-7.5. The plant is sensitive to waterlogging and may develop root rot if grown in poorly drained soils. The addition of organic matter to the soil can benefit growth and yield. Additionally, regular fertilization using a balanced fertilizer can help maintain soil fertility and promote plant health. It is important to note that Sphenostylis erecta is a nitrogen-fixing plant and can contribute to the soil's nitrogen content.
Cultivation methods for Sphenostylis erecta
Sphenostylis erecta can be propagated either by seeds or by stem cuttings. It is a hardy plant that requires a well-drained soil, with a neutral to slightly acidic pH. It should be planted in a location with full sunlight for best growth and yield.
The plant prefers hot and dry conditions, but it can also tolerate mild frost. It should be protected from strong wind and rain, especially during the flowering and fruiting stages to avoid physical damage and rotting of the pods.
Watering needs for Sphenostylis erecta
Sphenostylis erecta should be watered regularly during the growing season to ensure proper growth and yield. However, overwatering can lead to root rot and the plant's death. The frequency of watering should be adjusted according to the soil moisture level and weather conditions.
The plant is drought-tolerant and can survive for an extended period with little water. However, the yield may be reduced under such conditions.
Fertilization for Sphenostylis erecta
Sphenostylis erecta requires a balanced fertilizer with equal amounts of nitrogen, phosphorus, and potassium. The fertilizer should be applied during planting and should be reapplied during the flowering and fruiting stages to boost yield.
Organic fertilizers such as compost or manure can also be used to provide the necessary nutrients. However, care should be taken to ensure that excess nitrogen levels do not lead to vegetative growth at the expense of pod production.
Pruning for Sphenostylis erecta
Sphenostylis erecta requires minimal pruning as the plant has a bushy growth habit. Dead leaves and branches should be removed to prevent the spread of diseases and pests.
The plant can also be pruned to control its growth and improve its shape. Pruning should be done after the harvest to encourage new growth and flowering during the next season.
Propagation of Sphenostylis erecta
Sphenostylis erecta, also known as African Yam Bean, is a leguminous plant that is primarily propagated through seeds, but can also be propagated through stem cuttings. Here are the details of each propagation method:
Seed Propagation
The African Yam Bean plant produces pods that contain seeds. The seeds can be harvested once the pods have turned brown and dry. To improve the germination rate, scarification or soaking in water for 24 hours is recommended before planting. The seeds can be sown directly into the soil or started in small pots and transplanted into the garden once the seedlings are 4-6 weeks old. The ideal temperature range for seed germination is between 20-25°C. The seedlings take around 4-6 months to mature.
Stem Cutting Propagation
Sphenostylis erecta can also be propagated through stem cuttings. The stem cuttings should be taken from the mature plants during the active growing season. The cuttings should be around 10-15 cm long and preferably taken from the upper portion of the stem. The leaves on the lower half of the cutting should be removed, and the cutting should be dipped in rooting hormone powder. The cuttings can be planted in well-draining soil and kept in a warm, humid place until roots develop. Once the roots have developed, the new plant can be transplanted into the garden.
Disease and Pest Management for Sphenostylis erecta
Sphenostylis erecta, commonly known as the African Yam Bean, is an important legume crop grown mostly in Africa. Like other crops, S. erecta is susceptible to various pests and diseases that can cause significant yield losses. It is essential for farmers and gardeners to be aware of these pests and diseases and take necessary measures to manage them.
Common Diseases
The following are some of the common diseases that affect S. erecta:
- Anthracnose: This fungal disease causes brown patches on leaves, stems, and pods, eventually leading to premature defoliation and reduced yields. To manage this disease, farmers should remove and destroy infected plant parts, rotate crops and apply fungicides.
- Rust: Rust is a fungal disease characterized by yellow to orange pustules on leaves and stems. It can lead to defoliation and yield losses. Farmers should plant resistant cultivars, maintain good field hygiene, and apply fungicides to manage rust.
- Root rot: Root rot is caused by soil-borne fungi and can lead to stunted growth, wilting, and death of the plant. To prevent root rot, farmers should plant in well-drained soils, avoid soil compaction, and practice crop rotation.
Common Pests
The following are some of the common pests that affect S. erecta:
- Aphids: Aphids are small, soft-bodied insects that feed on plant sap. They can cause distorted growth, yellowing, and wilting of leaves. To manage aphids, farmers should use insecticides, introduce natural predators, and maintain good field hygiene.
- Spider mites: Spider mites are tiny pests that feed on the underside of leaves, causing them to turn yellow or brown. To control spider mites, farmers can use miticides, introduce natural predators, and maintain good field hygiene.
- Bean beetle: Bean beetles are small, dark insects that feed on the leaves and pods of S. erecta, causing defoliation and yield losses. Farmers can control bean beetles by handpicking or using insecticides.
Overall, managing diseases and pests in S. erecta involves a combination of preventative measures and early interventions. Farmers and gardeners should monitor their gardens or fields regularly and take necessary actions to prevent or manage diseases and pests.
