Overview of Crotalaria subspicata Polhill
Crotalaria subspicata Polhill, also known as sunn hemp, is a flowering plant native to Africa and widely grown in tropical and subtropical regions around the world. It belongs to the Fabaceae family and is a fast-growing, annual herbaceous plant that can reach up to two to three meters in height.
Description of Crotalaria subspicata Polhill
The leaves of Crotalaria subspicata Polhill are alternate, ovate or elliptical shaped with a length of up to 15 cm and a width of 10 cm. The plant's flowers are yellow and arranged in elongated clusters on the stem, hence the name "subspicata." The fruit is a narrow, curved pod containing seeds that are commonly used for animal feed and as green manure.
Common Names of Crotalaria subspicata Polhill
Crotalaria subspicata Polhill is commonly known as sunn hemp, brown hemp, Indian hemp, and Madras hemp. In some regions, it is also referred to as TAU and bakan gizo.
Uses of Crotalaria subspicata Polhill
Crotalaria subspicata Polhill has a wide range of uses. Its stems and leaves are used as fodder for livestock, and the seeds are used as a protein supplement for poultry and pigs. Due to its fast growth rate, it is a popular green manure crop that helps to improve soil fertility. Sunn hemp is also used for medicinal purposes to treat various ailments, including fever, tuberculosis, and diabetes.
Furthermore, sunn hemp is popularly used as a cover crop in sustainable agriculture practices. It suppresses weeds growth and is great for crop rotation. Its deep roots also retain nitrogen in the soil and reduce soil erosion
Additionally, the plant is a source of fiber and has been used to make ropes, bags, and paper. Its seeds are also used for oil production. Sunn hemp is used as a natural insecticide to control pests such as nematodes, root knot, and Fusarium.
Overall Crotalaria subspicata Polhill is a versatile plant with numerous benefits in various agricultural and medicinal applications, just perfect for any tropical or subtropical region.
Growth Conditions for Crotalaria subspicata Polhill
Crotalaria subspicata Polhill, commonly known as the sunn hemp, is a tropical plant species that belongs to the Fabaceae family. It is popularly cultivated as a green manure crop due to its remarkable ability to enrich soil fertility. The plant requires specific growth conditions to thrive. Below are some essential growth conditions for Crotalaria subspicata Polhill.
Light
Crotalaria subspicata Polhill thrives well in full sun conditions and requires a minimum of six hours of direct sunlight daily. The plant should not be grown in the shade as it will struggle to grow and mature healthily.
Temperature
The sunn hemp is a tropical plant that prefers warm, humid conditions. The ideal temperature range for growth is between 77°F to 86°F (25°C to 30°C). Temperatures below 50°F (10°C) may cause the plant to suffer from cold stress, which can stunt growth and cause leaf discoloration.
Soil
The sunn hemp prefers well-draining soils with a pH range of 5.5 to 7.5. The plant grows well in sandy loam and clay soils. It also requires adequate soil moisture, but waterlogged soil should be avoided as it can cause the plant roots to rot. Additionally, the soil should be rich in organic matter and nutrients to support optimal growth.
Crotalaria subspicata Polhill is an excellent crop for improving soil fertility and quality. By providing the ideal growth conditions discussed above, farmers can grow healthy and robust sunn hemp plants with ease.
Cultivation Methods for Crotalaria subspicata Polhill
Crotalaria subspicata Polhill or Sunn hemp plant is a warm-season annual crop that is easy to grow. It thrives in full sunlight and can grow up to six feet tall. The plant grows well in varying soil types, from sandy loam to clay-loam, with a pH of 5.5 to 7.5.
When planting Sunn hemp seeds, it is important to ensure that the soil temperature is above 60°F. Plant seeds ½ inch deep and two to four inches apart. To allow for good air circulation in between rows, space them about six to twelve inches apart. The germination period for Sunn hemp seeds is 4 to 10 days.
Watering Needs
Proper watering is essential during the first month of growth. Irrigating the crop at least three times a week is recommended until it establishes. Typically, mature Crotalaria subspicata Polhill plants require about 25 inches of water over the growing season. However, Sunn hemp can tolerate drought conditions better than many other crops.
Fertilization
Crotalaria subspicata Polhill plant has a high requirement for nitrogen. Consider applying 50 to 60 pounds of nitrogen per acre after the initial growth period. Supplementing with phosphorous and potassium will also help boost growth and yield. The best way to apply the fertilizer is by broadcasting it over the crop and then tilling it into the soil.
Pruning
Pruning Sunn hemp is not necessary for overall growth and development, but it can be useful for weed management. Trimming lower branches can prevent weed growth from shading out the Sunn hemp plants. If the plants become too tall or too dense, pruning the top of the plant can help improve air circulation and reduce disease pressure.
Propagation of Crotalaria subspicata Polhill
Crotalaria subspicata Polhill, commonly known as the sunn hemp plant, is a fast-growing and highly productive tropical legume with extensive applications in agriculture and soil improvement. Propagation of Crotalaria subspicata is generally achieved through seeds and stem cuttings.
Propagation through Seeds
Propagation through seeds is the most common and easiest method for growing Crotalaria subspicata. Seeds can be purchased from reputable seed suppliers or harvested from matured plants. To ensure successful germination, the seeds should be sown in a nursery bed or a well-drained seedling tray with a good quality seed-starting mix.
The seeds should be planted in a shallow furrow, covered lightly, and kept moist until they germinate, which usually takes 3-5 days. The seedlings can be transplanted into the field when they are 6-8 inches tall and have developed a strong root system.
Propagation through Stem Cuttings
Propagation through stem cuttings is a faster method than seed propagation, particularly when large quantities of plants are required. The best time for stem cutting propagation is during the vegetative stage of the plant, which is usually between 4-8 weeks after sowing or transplanting.
To propagate through stem cuttings, select healthy and disease-free stems with at least 3-4 nodes. Cut the stems into 6-8 inch-long sections and remove the leaves from the lower two-thirds of the stem. Dip the cut end of the stem into a rooting hormone and plant it into a well-draining rooting medium.
Provide adequate water and ensure that the cutting is kept moist until it has developed roots, which usually takes about 2-3 weeks. Once the roots have developed, the cuttings can be transplanted into the field.
Disease and Pest Management for Crotalaria subspicata Polhill
Crotalaria subspicata Polhill, commonly known as sunn hemp, is a popular cover crop that offers several benefits to the soil and the environment. However, like any other plant, sunn hemp is prone to several diseases and pests that can affect its growth and yield. Here are some of the common diseases and pests that affect sunn hemp and how to manage them.
Common Diseases
Fusarium wilt: This is a fungal disease that affects the roots and stems of sunn hemp, causing them to wilt and turn yellow. The best way to manage Fusarium wilt is to ensure proper crop rotation, use disease-free seeds, and avoid overwatering the plant. Fungicidal treatments can also help control the disease.
Bacterial blight: This is a bacterial disease that affects the leaves of sunn hemp, causing them to develop small, water-soaked spots that turn brown and dry out. The disease can also affect the stems and pods of the plant. Managing bacterial blight involves using disease-free seeds, maintaining proper plant spacing and ventilation, and avoiding overhead irrigation.
Rhizoctonia root rot: This is a fungal disease that affects the roots of sunn hemp, causing them to rot and turn brown. The disease can be managed by ensuring proper drainage, using disease-free seeds, and optimizing the pH and fertility levels of the soil. Fungicidal treatments can also help control the disease.
Common Pests
Aphids: These are small, soft-bodied insects that suck the sap from the leaves and tender shoots of sunn hemp, causing them to curl and yellow. To manage aphids, you can use insecticidal soap or neem oil, prune infested parts of the plant, and encourage natural predators like ladybugs and lacewings.
Cutworms: These are the larvae of nocturnal moths that feed on the stems and leaves of sunn hemp, causing the plant to wilt and die. To manage cutworms, you can use physical barriers like cardboard collars around the stems, apply Bacillus thuringiensis (Bt) insecticide, and encourage natural predators like birds and ground beetles.
Soybean loopers: These are caterpillars that feed on the leaves of sunn hemp, causing them to become skeletonized and brown. To manage soybean loopers, you can use insecticidal soap or neem oil, prune infested parts of the plant, and encourage natural predators like birds, wasps, and spiders.
In summary, disease and pest management is crucial for maintaining the health and productivity of sunn hemp. By following the best management practices outlined above, you can minimize the impact of diseases and pests on your sunn hemp crop and maximize its benefits.
