Description of Brachiaria umbratilis Napper
Brachiaria umbratilis Napper, commonly known as shaded signalgrass, is a species of perennial grass native to South America.
General Appearance
The grass can grow up to 1.5 meters in height, with a deep fibrous root system that allows it to establish well under heavy shade. It has a green color with light brown hairs on the sheaths and leaf blades.
Common Names
Brachiaria umbratilis is also known as shaded signalgrass, signal grass, and pasto K-88.
Uses
Brachiaria umbratilis is a popular forage grass used in livestock grazing systems due to its high biomass production, good nutritional value, and tolerance to low light, drought, and high temperatures. It is also used in erosion control and as a ground cover in landscaping and reclamation projects.
Light Requirements
The plant Brachiaria umbratilis Napper requires full sun exposure to thrive. It needs at least 6 to 8 hours of direct sunlight every day to grow and develop properly. Lack of sunlight may result in stunting of growth and poor flowering.
Temperature Requirements
The optimal temperature range for the growth of Brachiaria umbratilis Napper is between 20°C to 35°C. The plant cannot tolerate frost or extremely low temperatures. High temperatures above 35°C may cause stress to the plant resulting in leaf shedding or plant death.
Soil Requirements
The plant Brachiaria umbratilis Napper can grow well on a wide range of soils including sandy, loamy, and clay soils. However, the soil must be well-draining, rich in organic matter, and have a pH range of 5.5 to 7.5. Soil that is too acidic or alkaline may adversely affect the growth of the plant.
Cultivation
Brachiaria umbratilis Napper, also known as shaded signal grass, can be grown in a wide range of soils, including sandy soils with low fertility. The seeds can be sown directly in the soil or planted in seedbeds and later transplanted to the field. The ideal planting time is during the rainy season.
Watering Needs
Brachiaria umbratilis Napper needs adequate moisture to grow well. During the first few months after planting, the soil should be kept moist to encourage seed germination and establishment. Once established, the plant can withstand drought conditions due to its deep rooting system.
Fertilization
For optimum growth and yield, Brachiaria umbratilis Napper requires fertilization with nitrogen, phosphorus, and potassium. Soil testing is recommended to determine the nutrient requirements of the soil. Depending on the soil type and nutrient availability, the application rate of fertilizers may vary.
Pruning
Pruning is not mandatory for Brachiaria umbratilis Napper, but it can be done to promote thicker foliage and reduce the accumulation of dead plant material. Pruning can be done by mowing the grass to a recommended height of 4-6 inches. The cuttings can be used as animal feed or composted and used as organic fertilizer.
Propagation of Brachiaria umbratilis Napper
Brachiaria umbratilis Napper can be propagated through both sexually and asexually. However, the vegetative propagation methods are more popular due to the high demand for this forage plant.
Via Stem Cuttings
This is the most common method of asexual propagation of Brachiaria umbratilis. It involves planting pieces of the stem or rhizomes of the plant into healthy soils. It should be noted that the cuttings should be taken from healthy and mature plants to ensure successful propagation.
Via Division
The rhizomes of Brachiaria umbratilis can be divided into several segments, each with a healthy bud. The segments can then be planted in separate containers until they have developed roots, and then they can be transplanted into the field or garden.
Via Seed Propagation
The sexual propagation of Brachiaria umbratilis Napper is possible, but it is not commonly practiced. Seeds can be planted directly into the soil, ideally after the rainy season. Germination rates may vary, and it may take longer to achieve mature plants using this method, as compared to vegetative propagation.
Disease Management
Several diseases can affect Brachiaria umbratilis, including leaf spot, stem rot, and smut. Leaf spot is a common fungal disease that manifests through the appearance of small dark spots on leaves, leading to defoliation and productivity loss. Stem rot is caused by the fungus Sclerotinia sclerotiorum, characterized by the rotting of the lower stem and death of the plant. Smut is another fungal disease, characterized by the appearance of dark galls on the stems that later turn into black spores.
The best management practices for fungal diseases include the use of resistant cultivars, crop rotation, and appropriate field hygiene practices, such as removing infected plant parts and maintaining optimum plant density and nutrient levels. Fungicide applications may also be necessary in extreme cases.
Pest Management
Brachiaria umbratilis is vulnerable to several pests, including armyworms, cutworms, and mealybugs. Armyworm larvae feed on leaves, leading to plant defoliation, while cutworms feed on the stem, causing wilting and plant death. Mealybugs are sap-sucking pests that cause stunted growth, leaf yellowing, and premature plant death.
The most effective pest management practices include the use of pest-resistant cultivars, maintaining field sanitation, scouting for pests regularly, and using biological and cultural control measures such as predator releases and crop rotation. Chemical control measures such as insecticide and acaricide applications should only be a last resort and should be done following appropriate safety measures.
