Stylosanthes guianensis (Aubl.) Sw.
Stylosanthes guianensis (Aubl.) Sw. is a plant species belonging to the Fabaceae family. It is commonly known as "Pencilflower" or "Stylo". This plant is native to South America but has been introduced to several other regions across the world, including Africa, Asia, and Australia.
Appearance
Stylosanthes guianensis is a perennial herb that grows up to 1 meter in height. It has a deep-rooted taproot system that can reach up to 2 meters deep in the soil. The plant's stem is erect and branched, with leaves that are trifoliate, oval-shaped, and 2-5 cm long. The flowers are small and reddish-pink in color, arranged in dense clusters at the end of the stems, and resemble a pencil. The fruits are small pods containing several seeds.
Uses
The Stylosanthes guianensis plant has a variety of uses and benefits. It is primarily used for animal forage, as it has excellent nutritional qualities for cattle, sheep, and goats. It is also used in soil conservation and improvement, as its deep root system helps to prevent soil erosion and increase soil fertility. Additionally, the plant has medicinal properties, such as treating skin conditions, fever, and sore throat. The plant's leaves and stems can also be used as green manure, providing nitrogen for crops.
Light Requirements
Stylosanthes guianensis requires full sun for optimal growth and should be planted in areas that receive at least 6 hours of direct sunlight daily. Shade can be detrimental to the growth and productivity of this plant.
Temperature Requirements
The optimal temperature range for Stylosanthes guianensis growth is between 20-30°C (68-86°F). This plant can tolerate temperatures as low as 7°C (45°F) and as high as 35°C (95°F). However, extreme temperatures can affect productivity.
Soil Requirements
Stylosanthes guianensis prefers well-drained soils with a pH range of 6.0-7.5. It can grow in a variety of soil types but prefers sandy loam or clay loam soils. It is important to ensure that the soil has adequate fertility, including phosphorus and potassium. The plant is also sensitive to soil acidity, so it is necessary to maintain soil pH within the range.
Cultivation Methods
Stylosanthes guianensis (Aubl.) Sw. can be grown as a perennial or an annual crop, depending on the climate and management practices. The plant prefers well-draining soil with a pH range of 5.0-7.0. It is usually propagated through seeds, but stem cuttings can also be used in certain situations.
For perennial cultivation, the planting should be done during the rainy season when the soil is moist. The optimal planting density is around 10-15 kg of seed per hectare. The seed should be planted at a depth of 2-3 cm and covered with a thin layer of soil. Once the plants have established, they can be intercropped with other crops such as maize or beans.
For annual cultivation, the planting should be done in the dry season when the soil is dry. The seed rate for annual crops is higher, usually around 25-30 kg per hectare. The seed should be planted at a shallower depth of 1-2 cm and covered with a thin layer of soil. The crop can be harvested after 90-120 days of planting, depending on the variety.
Watering Needs
Stylosanthes guianensis (Aubl.) Sw. requires regular watering, especially during the establishment phase. The plant should be watered at least twice a week until it has fully established. After that, the watering frequency can be reduced to once a week if the soil is well-draining and retains enough moisture.
During the rainy season, the plant may not require additional watering unless there is a prolonged period of drought. However, during the dry season, the plant may require more frequent watering, especially if the soil is sandy or has poor water retention.
Fertilization
Stylosanthes guianensis (Aubl.) Sw. is a legume, meaning it can fix atmospheric nitrogen through its roots. However, for optimal growth and productivity, the plant requires additional fertilization.
The recommended fertilizer for Stylosanthes guianensis is a balanced NPK fertilizer (e.g., 15-15-15) applied at a rate of 100 kg per hectare. The fertilizer should be applied at planting and then again after the first cut. It is advisable to carry out a soil test before applying any fertilizer to determine the specific needs of your soil.
Pruning
Pruning is an important management practice for Stylosanthes guianensis (Aubl.) Sw. to promote better forage quality and higher yields. The plant should be pruned regularly to remove old and unproductive stems.
The first pruning should be carried out when the plant is 30-45 cm tall and then every 6-8 weeks thereafter. The plant should be pruned to a height of 10-15 cm above ground level, leaving behind fresh and healthy stems.
Pruning should be done using a sharp machete or pruning shears to avoid damaging the stems. The pruned stems can be used for mulching or as animal feed.
Propagation of Stylosanthes guianensis (Aubl.) Sw.
Stylosanthes guianensis (Aubl.) Sw. is propagated through both sexual and asexual methods. The primary aim of propagation is to produce new plants with desirable traits that can be used for grazing, forage, and soil conservation purposes.
Sexual Propagation
The sexual propagation of Stylosanthes guianensis is done through seeds. After flowering, the plant produces elongated pods containing several seeds. These seeds are harvested and sown directly into the soil, or they can be stored for future use. When planting, the seeds are usually drilled into the soil, and the depth of planting should be about 2-3 cm. The best time to sow the seeds is during the rainy season when there is sufficient moisture to promote seed germination.
Asexual Propagation
Asexual propagation of Stylosanthes guianensis is achieved through vegetative means. This method produces clones of the parent plant, which are genetically identical to the parent. It is used to propagate plants with desirable traits quickly.
The most common asexual propagation method for Stylosanthes guianensis is stem cutting. Stem cuttings are obtained from mature, healthy, and disease-free plants. The cuttings should be about 10-15 cm long with at least two nodes. After cutting, the leaves on the lower part of the stem should be removed, and the cutting should be dipped in rooting hormone, then planted into a well-prepared soil or rooting medium. Irrigation is essential for the cuttings to take root, and they should be covered with a plastic bag or kept in a humid chamber to maintain high humidity. Rooting usually occurs within 2-3 weeks, after which the cuttings can be transplanted to their final location.
Disease and Pest Management of Stylosanthes guianensis (Aubl.) Sw.
Stylosanthes guianensis (Aubl.) Sw. is a leguminous forage crop grown for its high-quality forage and nitrogen-fixing capabilities. Although the plant is hardy and adaptable to different environments, it is susceptible to various diseases and pests that can cause significant yield losses. Effective disease and pest management strategies are, therefore, essential to ensure the plant’s maximum productivity.
Common diseases affecting Stylosanthes guianensis
1. Anthracnose: Anthracnose is a fungal disease that causes leaf spots, defoliation, and stem browning. Management options include the use of resistant cultivars, regular pruning of infected plant parts, and application of fungicides.
2. Root rot: Root rot is a common disease caused by soil-borne pathogens that affect the plant’s roots, leading to stunted growth and poor yield. Crop rotation, soil drainage improvement, and fungicide application are some effective management options.
3. Leaf blight: Leaf blight is caused by a fungus that causes yellowing, wilting, and defoliation of leaves. Removing infected leaves and application of fungicides are some effective management practices.
Common pests affecting Stylosanthes guianensis
1. Spider mites: Spider mites are common pests that cause leaf yellowing, defoliation, and stunted growth. Application of miticides, regular irrigation, and planting of resistant cultivars are effective management practices.
2. Stem borers: Stem borers are known to cause damage to the plant’s stems, leading to wilting and stunted growth. Management options include the use of insecticides and regular pruning of infected stems.
3. Nematodes: Nematodes are parasitic worms that cause root galls, stunted growth, and poor yield. Crop rotation, use of resistant cultivars, and application of nematicides are effective management practices.
Conclusion
Disease and pest management are essential in ensuring the productivity of Stylosanthes guianensis (Aubl.) Sw. Effective management strategies such as the use of resistant cultivars, regular pruning of infected plant parts, and application of appropriate pesticides and fungicides play a crucial role in disease and pest management. Early detection and management of diseases and pests are vital in minimizing yield losses and ensuring maximum productivity of the plant.
