Overview
Sorghum bicolor (L.) Moench var. virgatum (Hack.) de Wet & Huckabay, also known as Johnson grass or veldtgrass, is a perennial species of grass that belongs to the Poaceae family. This plant is native to Africa, but it has become widespread in other parts of the world, including Australia, North America, and Europe. Sorghum bicolor var. virgatum is known for its hardiness, drought tolerance, and its ability to grow in a wide range of soil types.
Common Names
Johnson grass is the most common name given to Sorghum bicolor var. virgatum, but it is also known by other names such as veldtgrass, Guinea grass, and Aleppo grass. In different parts of the world, this plant can have different local names, which can sometimes be based on the animal species that often graze on the plant.
Uses
The Sorghum bicolor var. virgatum plant has several uses, some of which are beneficial, while others can be harmful. One of the most significant benefits of this plant is its use as a feed for livestock. Due to its hardiness, it can grow even in harsh conditions, making it an ideal source of forage for farmers. In some parts of the world, this plant is also used as a biofuel crop due to its high cellulose content.
However, Johnson grass can also be harmful in some situations. The plant has allelopathic properties and can suppress the growth of other nearby plants. Additionally, this plant is considered an invasive species in some parts of the world. It can spread rapidly, especially in areas where cultivation practices are disrupted, such as roadsides and abandoned fields.
Appearance
The Sorghum bicolor var. virgatum plant has a distinctive appearance with long, narrow leaves that grow up to 90 cm in length. The plant can grow up to two meters in height, with a dense and fibrous root system that can penetrate deep into the soil. The plant produces a large number of seeds, up to 40,000 per plant, which are dispersed by wind, water, and animals.
Johnson grass can be easily recognized by its tall, dense inflorescence of large, feathery seed heads, which can grow up to 60 cm long. The seed heads are light brown and can persist on the plant for several months. The stalks of the plant are thick and have a blue-green hue, with a waxy coating that gives them a shiny appearance.
Light Requirements
Sorghum bicolor var. virgatum requires full sun exposure in order to grow and develop properly. This plant thrives in areas with high levels of light intensity throughout the day. Insufficient light can lead to poor growth and low yield.
Temperature Requirements
Temperature is a crucial factor for the growth and development of Sorghum bicolor var. virgatum. This plant requires warm temperatures ranging from 25°C to 35°C for germination and growth. In general, it prefers a hot and dry climate. Extremely high temperatures, however, can result in heat stress and negatively impact growth and yield.
Soil Requirements
Sorghum bicolor var. virgatum can grow in a variety of soils, including sandy, loamy, and clayey soils. However, it prefers well-draining soils with good fertility and a pH range of 6.0 to 8.5. This plant can tolerate slightly acidic to alkaline soils, but excessively acidic or alkaline soils can be detrimental to its growth. Adequate soil moisture is also crucial for optimum growth.
Cultivation of Sorghum bicolor (L.) Moench var. virgatum (Hack.) de Wet & Huckabay
Sorghum bicolor (L.) Moench var. virgatum (Hack.) de Wet & Huckabay is a warm-season native grass that is cultivated as a forage crop. It is easy to grow and has a high drought tolerance, making it suitable for cultivation in arid and semi-arid regions. Below are some guidelines for cultivating this crop:
Watering Needs
Sorghum bicolor (L.) Moench var. virgatum (Hack.) de Wet & Huckabay requires moderate watering. It can tolerate periods of drought but still needs enough water for its roots to absorb nutrients from the soil and for the plant to maintain its growth rate. You should water the crop once or twice a week, depending on your location's weather conditions.
Fertilization
Fertilization is key in ensuring optimal growth and yield of Sorghum bicolor (L.) Moench var. virgatum (Hack.) de Wet & Huckabay. Apply 60-80 lbs of nitrogen per acre at planting time, and top-dress with another 30-50 lbs of nitrogen later during the growing season. Additionally, supplement the soil with phosphorus and potassium to promote root development and overall plant growth.
Pruning
Pruning Sorghum bicolor (L.) Moench var. virgatum (Hack.) de Wet & Huckabay is not necessary. However, if you notice overgrown stems, you can cut them back to about 6 inches above the soil surface. This will promote the growth of new shoots and keep the plant looking neat. It is always best to prune during the growing season and avoid taking off more than a third of the plant's growth at one time.
Propagation of Sorghum bicolor (L.) Moench var. virgatum (Hack.) de Wet & Huckabay
Sorghum bicolor (L.) Moench var. virgatum (Hack.) de Wet & Huckabay, commonly known as Johnson Grass, can be propagated through multiple methods, including seeds, rhizomes, and tillers.
Propagation through Seeds
Seeds are the most common method of propagation for Sorghum bicolor var. virgatum. The best time to sow seeds is in the early spring, when soil temperatures reach approximately 60-65°F. The seeds should be planted in well-drained soil to a depth of 1/4 to 1/2 inch and spaced 12 to 16 inches apart. Water the seeds regularly to maintain soil moisture until sprouts emerge, which generally takes about 10 days.
Propagation through Rhizomes
Sorghum bicolor var. virgatum can also be propagated through rhizomes. Rhizomes are underground stems that produce roots and shoots. To propagate through rhizomes, dig up the plants in the fall after the first killing frost. Cut the rhizomes into 2-3 inch pieces, ensuring that each piece has at least 1-2 buds. Plant the rhizome sections horizontally, just below the soil surface, and water well to encourage root growth.
Propagation through Tillers
Sorghum bicolor var. virgatum can also be propagated through tillers. Tillers are lateral shoots that emerge from the base of mature plants. To propagate through tillers, select healthy, established plants and cut the tillers at the soil surface with a sharp knife. Plant the tillers in well-drained soil, ensuring that the base of the tiller is level with the soil surface. Keep the soil moist until the new plants are established.
Disease and Pest Management for Sorghum bicolor var. virgatum
Sorghum bicolor var. virgatum, commonly known as Johnson grass, is a well-known perennial grass that can grow up to six feet tall. It is used for forage, hay production, turfgrass, and biofuel. Although this plant is drought-tolerant and can grow in a variety of soils, it is still susceptible to diseases and pests. Here are some common diseases and pests that may affect Sorghum bicolor var. virgatum and ways to manage them:
Diseases
1. Anthracnose: This is a fungal disease that can cause lesions on leaves and stems. It can spread quickly, especially in hot and humid weather. To manage this disease, you can choose resistant varieties, apply fungicides, and practice crop rotation.
2. Ergot: Ergot is a fungal disease that can produce dark purple or black masses on the seed heads. Infected plants may have reduced seed production, and the seeds produced are often smaller and shriveled. To prevent an ergot outbreak, you can practice crop rotation and avoid planting sorghum in areas where ergot previously occurred.
3. Rust: This fungal disease can cause orange or reddish spots on leaves and stems. It can spread quickly, especially in warm and humid weather. You can manage rust by choosing resistant varieties and applying fungicides.
Pests
1. Sugarcane Aphids: These pests can cause significant damage to the plant by sucking the sap out of the leaves and stems. Infestations can lead to yield losses and reduced quality of forage or hay. To manage sugarcane aphids, you can release natural enemies such as ladybugs, lacewings, and parasitic wasps, and apply insecticides if necessary.
2. Cutworms: Cutworms are small caterpillars that can cut the plants at the base and cause severe damage to the crop, especially in the early stages of growth. To prevent cutworm outbreaks, you can practice crop rotation and avoid planting sorghum in areas where cutworms previously occurred. Birds, beneficial nematodes, and insecticides can also help manage cutworms.
3. Fall Armyworms: Fall Armyworms can cause significant damage to the plant by consuming the leaves, stems, and grain. Infestations can lead to yield losses and reduced quality of forage or grain. To manage Fall Armyworms, you can release natural enemies such as parasitic wasps, tachinid flies, and birds. You can also apply insecticides if necessary.
In conclusion, Sorghum bicolor var. virgatum is a hardy plant that can tolerate the adverse conditions and produce significant yield. However, it is still susceptible to diseases and pests that can reduce the quality and quantity of the forage or grain. By applying appropriate management practices such as crop rotation, resistant varieties, natural enemies, and pesticides, you can minimize the impact of diseases and pests on your Sorghum bicolor var. virgatum crop.