Overview
Rhynchosia stipitata Verdc., also known as Natal bean or Inkala, is a flowering plant that belongs to the Fabaceae family. It is native to eastern and southern parts of Africa and is widely cultivated in other areas due to its nutritional and medicinal properties. This plant is highly valued for its ability to fix nitrogen in the soil and is used as a cover crop to improve soil fertility.
General Appearance
Rhynchosia stipitata Verdc. is a semi-woody perennial plant that can grow up to 1.5 meters in height. It has a sprawling, climbing or trailing growth habit and produces yellow flowers that bloom mainly from May to September. The leaves are trifoliate with a central leaflet that is larger than the side ones. The stem is slightly hairy and woody at the base. The fruit is a pod that contains several seeds.
Common Names
Rhynchosia stipitata Verdc. has several common names including Natal bean, Inkala, and shikua in Tanzania. The name Natal bean is derived from its place of origin, Natal in South Africa.
Uses
The seeds of Rhynchosia stipitata Verdc. are edible and are rich in protein, fiber, and other essential nutrients. They are a common food source for many communities in Africa, particularly in Tanzania and Kenya, where they are used to make curries, stews, and soups. The plant is also used as a traditional medicine to treat various ailments such as diarrhea, constipation, and coughs. The leaves and roots are boiled and consumed as a decoction to relieve pain and inflammation. Moreover, Rhynchosia stipitata Verdc. is used as a soil cover or green manure to improve soil fertility, prevent soil erosion, and control weeds. It is also effective in nitrogen fixation, which makes it an ideal plant for intercropping with cereals.
Growth Conditions for Rhynchosia stipitata Verdc.
Rhynchosia stipitata Verdc. is a hardy perennial plant that thrives in tropical climates. Understanding the plant's growth conditions is essential for successfully growing and cultivating the plant.
Light Requirements
Rhynchosia stipitata Verdc. requires direct sunlight for at least six hours each day. The plant does not tolerate shade and may experience stunted growth if it does not receive adequate sunlight. As such, the plant should be grown in an area with no obstruction to sunlight.
Temperature Requirements
The optimal temperature range for Rhynchosia stipitata Verdc. growth is between 25°C to 30°C. The plant does not tolerate extreme temperatures below 10°C or above 40°C. Therefore, it is essential to place the plant in an area with temperatures that fall within its optimal range.
Soil Requirements
Rhynchosia stipitata Verdc. thrives in well-drained soil with a pH between 6.0 and 7.0. The soil should be rich in organic matter to support the plant's growth. The plant also requires consistent moisture, but the soil should not be waterlogged as it may lead to root rot. Additionally, regular fertilization is essential for the plant's growth and development.
By understanding the growth conditions of Rhynchosia stipitata Verdc., growers can create an ideal environment for the plant's growth and ensure a bountiful harvest.
Cultivation Methods
Rhynchosia stipitata Verdc. is a subtropical plant that can grow in most soils, provided the soil is well-drained and has a pH of between 6.0 and 7.5. It can be grown from seed or propagated through stem or root cuttings. Propagation through cuttings is preferred as it is faster and more reliable. The plant should be grown in an area that receives full sunlight or partial shade. The planting should be spaced 35-50 cm apart from each other to allow for proper growth and development.
Watering Needs
Rhynchosia stipitata Verdc. requires moderate watering. The soil should be kept evenly moist but not waterlogged, as too much water can lead to root rot. The frequency of watering will depend on the soil and weather conditions. In general, the plant should be watered thoroughly once a week during the growing season. During the dormant period, watering should be reduced.
Fertilization
The plant should be fertilized once during the growing season with a balanced fertilizer. A slow-release fertilizer can also be used. Over-fertilization should be avoided as it can lead to excessive foliage growth at the expense of flowering.
Pruning
Rhynchosia stipitata Verdc. does not require regular pruning. However, dead or diseased branches should be removed as soon as they are noticed. Pruning can also be done to control the size and shape of the plant or to promote better flowering. Pruning can be done after flowering season or in early spring before new growth begins.
Propagation of Rhynchosia stipitata Verdc.
The Rhynchosia stipitata Verdc. plant can be propagated through different methods. These methods are as follows:
Seed propagation
Seeds are the most common method used to propagate Rhynchosia stipitata Verdc. plants. Collect seed pods once they are mature and dry. Break the pods open and collect the seeds. The seeds should be treated with sulfuric acid to break their hard coat before planting. Soak the seeds in water for about 12 hours before sowing them. Plant the seeds in a well-draining soil mix, about 1 inch deep. Keep the soil moist but not waterlogged. Germination can take 2-3 weeks.
Cuttings propagation
Asexual propagation through stem cuttings is also possible but less common. The cuttings should be taken in the early morning, and a 4-inch long stem cutting with one or two leaves should be cut, making sure to cut just below a node. Remove the leaves from the lower one-third of the stem cutting, apply rooting hormone, and plant into a sterilized, well-draining soil mix. Place rooting container in a warm bright spot, avoiding direct sunlight and keep the soil moist.
Disease management
Any Rhynchosia stipitata Verdc. seed or cutting should be acquired from disease-free plants. Proper management of diseases, pests and environmental conditions will ensure the success of propagation.
Disease Management
The plant Rhynchosia stipitata Verdc. is susceptible to a few diseases that may affect its growth and yield. Some of the common diseases that may affect the plant include:
- Anthracnose: This fungal disease attacks the leaves, stems, and pods of the plant, causing yellowing, wilting, and premature defoliation. Control measures include crop rotation, pruning infected plant parts, and the use of fungicides.
- Leaf spot: Caused by the fungus Cercospora rhynchosiae, this disease causes yellowing, necrosis, and defoliation of the leaves. Cultural practices such as sanitation, crop rotation, and proper irrigation management can help prevent the disease. Fungicides are also an effective way of controlling the disease.
- Rust: This fungal disease manifests as orange-brown pustules on the leaves, stems, and pods of the plant, which can reduce the photosynthetic efficiency of the plant. Control measures include the removal of infected plant parts, crop rotation, and the use of fungicides.
Pest Management
There are a few pests that may attack Rhynchosia stipitata Verdc., affecting the yield and quality of its produce. Some of the common pests that may affect the plant include:
- Aphids: These small soft-bodied insects suck the sap from the leaves and stems of the plant, causing stunting, distortion, and yellowing of the leaves. Control measures include the use of insecticidal soap, neem oil, or horticultural oil.
- Bean leaf beetle: This pest feeds on the leaves, flowers, and pods of the plant, causing defoliation and yield loss. Control measures include planting early to avoid heavy infestations, crop rotation, and the use of insecticides.
- Soybean looper: This caterpillar feeds on the leaves of the plant, causing defoliation and yield loss. Control measures include the use of Bacillus thuringiensis (Bt) or spinosad-based insecticides.
