Overview
Sphenostylis briartii, also known as African Yam Bean, is a leguminous plant species that belongs to the family Fabaceae. The plant is native to West Africa, where it has been cultivated for centuries as a food crop.
Appearance
The African Yam Bean plant can grow up to 2 meters tall and has a sturdy stem with trifoliate leaves that are ovate, with pointed tips and serrated margins. The flowers are small and range from white to pink in color. The pods are elongated and can grow up to 20cm in length, containing up to six seeds that have a hard seed coat.
Common Names
African Yam Bean is known by a variety of names, including Sphenostylis stenocarpa, Sphenostylis angustifolia, and Sida cordifolia. It is also known by local names such as Oju (Nigeria), Ezpro (Togo), and Esuru (Ghana).
Uses
The African Yam Bean is highly valued for its nutritious seeds, which are rich in protein, complex carbohydrates, and essential minerals. The seeds can be used to make a variety of dishes, including porridge, soup, or roasted as a snack. The plant is also used as a cover crop to improve soil fertility and control erosion.
Light Requirements:
Sphenostylis briartii grows best under full sun exposure, but can also withstand partial shade. It requires a minimum of 6 hours of direct sunlight exposure every day to thrive properly.
Temperature Requirements:
The plant grows well in temperatures between 21°C to 27°C (70°F to 80°F). It is intolerant to frost and cannot survive in excessively cold temperatures. At temperatures below 18°C (65°F), growth is significantly slowed down, and leaf drop may occur.
Soil Requirements:
The plant requires well-draining soils with rich loamy texture. Sphenostylis briartii can also grow on sandy soils that are well-drained. It prefers a pH range of 5.5 to 6.5. The plant can tolerate slightly acidic or neutral soils, but will not thrive well in alkaline soils.
Cultivation methods
Sphenostylis briartii, commonly known as African Yam Bean, is a hardy deciduous climbing plant that grows in tropical and subtropical regions. It can be grown both as a perennial and as an annual in colder climates. The plant requires full sun and well-draining soil to thrive. The ideal temperature range for growing African Yam Bean is between 20-30°C.
The seeds of Sphenostylis briartii can be sown directly into the ground or in containers. If sowing directly, ensure that the soil has warmed up and the danger of frost has passed. Sow the seeds at a depth of 2-3 cm and cover lightly with soil. Water the soil regularly to keep it moist. The plant takes around three to four months to mature.
Watering needs
Watering is an essential part of growing Sphenostylis briartii. The plant requires regular watering to ensure that the soil stays moist. However, over-watering can lead to root rot and other diseases, so it's crucial to strike a balance. The water requirement may vary depending on the climate and temperature. Generally, water the plant every three to four days in hot weather and once a week in cooler weather.
It's also essential to note that the plant is sensitive to drought, so it's crucial to keep an eye on the soil moisture levels. Water the plant deeply to ensure that the water reaches the roots and gets absorbed by the soil. Avoid overhead watering, as it can lead to the development of fungal diseases if the leaves remain wet for prolonged periods.
Fertilization
Fertilization is crucial for the healthy growth of Sphenostylis briartii. It's recommended to use a balanced fertilizer with a 10-10-10 or 20-20-20 NPK ratio. Apply the fertilizer every two weeks during the growing season, but cease fertilization when the plant starts flowering. Over-fertilization can lead to excessive foliage growth, reducing the yield of the plant.
It's also recommended to enrich the soil with organic matter such as compost and well-decomposed manure before planting. This enhances soil fertility, promoting healthy growth of the plant.
Pruning
Sphenostylis briartii doesn't require significant pruning, but it's recommended to pinch off the tips of the plant when it reaches around 30 cm in height. This promotes bushy growth and enhances the development of lateral shoots.
It's also essential to remove dead, diseased, or damaged parts of the plant to prevent the spread of diseases. Additionally, it's recommended to trellis or stake the plant to provide support as it grows.
Propagation of Sphenostylis briartii (De Wild.) Baker f.
Sphenostylis briartii (De Wild.) Baker f., commonly known as African Yam Bean, is a versatile and hardy plant that can be propagated by various methods, including seed propagation, stem cuttings, and tuber division.
Seed propagation
The most common method of propagating Sphenostylis briartii is through seed propagation. The seeds can be obtained from mature seed pods of healthy and disease-free plants. Seeds obtained from pod or soil should be properly dried and cleaned before sowing. The seeds can be sown directly in the field or in seedbeds. In warm climates, the seeds can be sown all year round; in areas with frost, the seeds should be sown after the last frost.
The depth of sowing should be 2-4 cm, and seeds should be spaced at 10-15 cm apart. The seedlings will emerge within 10-14 days. It is essential to water the seedlings regularly in the first six weeks of growth to ensure optimal growth and yield.
Stem Cuttings
Sphenostylis briartii can also be propagated through stem cuttings. The cuttings should be taken from healthy and disease-free mother plants. It is recommended to take cuttings in early spring or late fall when the plants are dormant. The cuttings should be at least 15 cm long, and all the leaves except the top two should be removed. The cuttings should be dipped in rooting hormone before planting.
The cuttings should be planted at a depth of 5-7 cm in well-drained soil and watered frequently. The roots will develop within 4-5 weeks. Once the roots develop, the cuttings can be transplanted into the field or in larger pots.
Tuber Division
Propagating Sphenostylis briartii through tuber division is recommended for mature plants. The tubers should be dug out of the ground after the growing season is over. The tubers should be adequately washed before they are cut into smaller pieces. Each tuber piece should have at least one healthy bud for the development of new shoots.
The tuber pieces should be planted at a depth of 10-15 cm in well-drained soil and watered frequently. The new shoots will emerge within 2-4 weeks. Once the new shoots have grown to a height of 10-15 cm, they can be transplanted to the field or larger pots.
Disease and Pest Management for Sphenostylis briartii
Sphenostylis briartii is an important legume crop grown in Africa. It is relatively resistant to many diseases and pests, but some management practices are necessary to prevent loss and maximize production. Here are some of the common diseases and pests that might affect the plant and ways to manage them:
Fungal Diseases
Sphenostylis briartii is susceptible to various fungal diseases, including Fusarium wilt, root rot, and powdery mildew. These diseases often attack plants growing in poorly drained soil or affected by drought.
To manage these diseases, growers should ensure that the plant's growing conditions are optimal. Growers can also apply fungicides to control the spread of the fungal disease. However, the use of fungicides should be done with caution as resistance and environmental concerns may be issues in some cases. Crop rotation can also help suppress fungal pathogens in the soil.
Bacterial Diseases
The bacterial blight is the most significant bacterial disease affecting Sphenostylis briartii. It spreads through the wind and rain, making it difficult to manage.
Cultural control practices are effective in managing bacterial disease. Planting disease-free seeds, avoiding planting during wet conditions, and crop rotation can help prevent bacterial disease. Growers can also employ resistant varieties and mulch to minimize the likelihood of infection.
Insect Pests
Insect pests such as aphids, thrips, and whiteflies can cause damage to Sphenostylis briartii. They cause feeding damage to the leaves and stems, leading to stunted growth and poor yields.
Integrated Pest Management (IPM) is the best way to control insect pests. Approaches such as using biological control agents, employing resistant varieties, and physical control measures like spraying or removing infested plants are effective in managing insect pests. It is essential to monitor plants regularly so that action can be taken at the earliest indication of pest infestation.
Nematodes
Nematodes are small organisms that live in the soil. They attack the roots of Sphenostylis briartii, reducing plant growth and yield.
Growers can apply nematicides to control nematodes. However, this should be done with caution and following guidelines to minimize environmental risks and health hazards. The use of resistant varieties, crop rotation, and intercropping can also minimize the damage caused by nematodes.
By employing pest and disease management strategies, Sphenostylis briartii can provide maximum yield and nutrition to those who rely on it.
