Brachiaria grass seeds offer a promising solution for sustainable agriculture, particularly in tropical and subtropical regions. This resilient tropical forage grass is gaining recognition for its adaptability and ability to thrive in challenging environments. Understanding how to effectively utilize these seeds can contribute to improved livestock production and enhanced soil health.
Characteristics of Brachiaria Grass Seeds
Brachiaria grass seeds are egg-shaped, measuring between 4 to 5 millimeters long and 2 to 3 millimeters wide. Their surface is smooth with a subtle shine, often featuring fine hairs near one end and a 2-millimeter membrane connecting to the stem. A kilogram contains approximately 130,000 seeds, indicating their small size.
Different Brachiaria species, including Brachiaria decumbens, Brachiaria brizantha, and Brachiaria ruziziensis, show slight variations in seed characteristics. For instance, the ‘Mulato II’ hybrid, derived from Brachiaria ruziziensis, is apomictic, meaning it is genetically stable and can last for many years. When flowering, ‘Mulato’ has maroon stigmas, while ‘Mulato II’ has white stigmas. These distinctions influence growth habits and suitability for specific agricultural applications.
Cultivation and Establishment
Cultivating Brachiaria grass from seeds requires thorough land preparation, especially due to their small size. The land should be cleared of bushes and perennial weeds before plowing, then harrowed twice for a fine seedbed. If using a hand hoe, break down large soil clumps. Herbicides like Round-Up can eliminate stubborn weeds such as couch grass before plowing.
Brachiaria grass can be planted by direct sowing in the field or by sowing seeds in a nursery for later transplanting. For direct sowing, make shallow holes (1-2 cm deep) 30 cm apart, with 45 cm between rows. A recommended seed rate is 8 kg per hectare (3.2 kg per acre), with 4-5 seeds placed per hole and covered lightly (not exceeding 2 cm deep). For nursery establishment, prepare a 1×5 meter area with raised seedbeds. Seedlings will be ready for transplanting within 4-6 weeks during the wet season, ideally during cooler hours.
Applications in Agriculture
Brachiaria grass is primarily used as high-quality forage for livestock in agricultural systems. It offers excellent nutritional characteristics, with crude protein content from 14% to 22% and digestibility between 55% to 66% in 25-35 day regrowth. This high nutritive value increases meat and milk production, with Mulato II grass reportedly raising milk yields by 11% in dry seasons and 23% in rainy seasons. It is highly palatable to grazing ruminants, maintaining palatability even into the dry season due to delayed flowering.
Beyond forage, Brachiaria grass effectively controls soil erosion with its extensive, deep root systems. These root networks also improve soil health by enhancing water uptake, facilitating carbon sequestration, and improving nitrogen use efficiency. The grass can also reduce soil nitrous oxide emissions through biological nitrification inhibition. Its robust root system and tolerance to low soil fertility also make it valuable in crop protection strategies and for improving overall soil fertility.
Factors Affecting Growth
Brachiaria grass growth and yield are influenced by environmental and biological factors. Brachiaria thrives in areas with medium to high rainfall; annual rainfall above 700 millimeters is generally suitable, though some hybrids perform in areas with as low as 700 millimeters. Optimal growth occurs in sub-humid climates, which have moderate rainfall favoring maximum growth rates. While tolerant of acid and neutral soils with moderate to low fertility, including those with high aluminum levels, Brachiaria grass is more productive in fertile soils with irrigation.
Nutrient requirements are also a consideration; the grass responds well to nitrogen fertilizer. For intensive production or seed yield, nitrogen fertilizer supplementation may be needed, with application rates from 50 kg/ha/year in sub-tropics to 350 kg/ha/year in the tropics. Common challenges include pests like red spider mites and armyworms, which can be managed by maintaining healthy plants and keeping surrounding areas weed-free. Diseases like leaf rust and leaf blight can also impact productivity, with environmental factors such as rainfall influencing their development.