Palisade grass is a perennial tropical forage species native to Africa that has become one of the most widely planted pasture grasses in the world, particularly across Latin America. Formally known as Urochloa brizantha (and still frequently called Brachiaria brizantha in older literature), it dominates tens of millions of hectares of Brazilian pastureland alone, feeding the beef and dairy herds that underpin the country’s enormous livestock economy. Its popularity comes down to a combination of aggressive growth, reasonable tolerance of poor soils, and the ability to produce decent forage even without heavy management, though the grass turns out to be far more scientifically interesting than that quick summary suggests.
The Name Problem
If you start reading about palisade grass, you will quickly notice that some papers call it Brachiaria brizantha and others call it Urochloa brizantha. This is not a typo or a regional preference. The genera Brachiaria and Urochloa have been taxonomically entangled for decades. Molecular and morphological analyses have shown that Brachiaria and Urochloa, taken together, form a paraphyletic group with other genera like Eriochloa and Melinis, meaning the old genus boundaries did not reflect actual evolutionary relationships.1PubMed Central. Molecular and morphological phylogenetic analysis of Brachiaria and Urochloa (Poaceae) The upshot is that many taxonomists now place the important forage species under Urochloa, but the old Brachiaria name remains deeply embedded in agricultural research, seed catalogs, and farmer vocabulary. Both names refer to the same plant, and you will encounter both interchangeably in the literature for a long time yet.
The cultivar most commonly encountered worldwide is “Marandu,” released in Brazil in the 1980s and still occupying an enormous share of improved pastureland. Other cultivars include “Xaraés” (also spelled “Xaraes”), “Piatã,” and “BRS Paiaguás,” each bred or selected for slightly different traits like regrowth speed, drought tolerance, or leafiness.
Why It Took Over Tropical Pastures
Palisade grass is a C4 species, meaning it uses a photosynthetic pathway that is especially efficient under the hot, high-light conditions of the tropics. It grows vigorously across a wide range of soil fertility levels, and its dense, tufted growth habit shades out many weeds once established. But the feature that sealed its dominance, especially in Brazil, was its resistance to spittlebugs, a group of sap-sucking insects in the family Cercopidae that devastated earlier pasture grasses like signal grass (Brachiaria decumbens). The Marandu cultivar showed strong resistance to spittlebug nymphs, and the mass adoption of Marandu in the 1980s and 1990s was largely a response to spittlebug damage on other species.
The grass also tolerates moderate drought better than many tropical forages, partly through structural adjustments at the leaf level. When soil moisture drops, palisade grass leaves become thinner as the epidermis and vascular bundles shrink, while the proportion of the upper epidermis increases, changes that reduce water loss through the leaf surface.2SciELO / Revista Ceres. Anatomical adaptations to different soil moisture contents in palisade grass and smooth pigweed These are not dramatic survival mechanisms compared to truly drought-adapted species, but they help the grass persist through the dry seasons common in the Brazilian Cerrado and similar environments.
Forage Quality and What Animals Actually Get From It
As a forage, palisade grass is solidly mid-range for tropical grasses. It is not as nutritious as well-managed temperate pastures, but it provides a reliable feed base in regions where temperate species cannot survive. The crude protein content of the grass is heavily influenced by nitrogen fertilization: as nitrogen application rates rise, protein content increases in a roughly linear fashion, while the proportion of structural fiber (neutral detergent fiber) drops.3Animal Feed Science and Technology. Chemical composition and in vitro ruminal digestibility of hand-plucked samples of Xaraes palisade grass fertilized with incremental levels of nitrogen Nitrogen fertilization also improves digestibility, both for dry matter and for the fiber fraction itself, which means the animal extracts more energy per bite from fertilized swards.
In practice, though, most palisade grass pastures in the tropics receive little or no nitrogen fertilizer. This is one of the core tensions in tropical livestock systems: the grass can produce excellent forage when well-managed and fertilized, but much of it is grown extensively on low-input operations where protein and digestibility are relatively low. Animals on unfertilized palisade grass pastures often need supplementation to maintain weight during the dry season, when the grass matures and its nutritional value falls further.
How Grazing Height Changes Everything
One of the most practical findings from research on palisade grass involves sward height at the time cattle start grazing. A study on Marandu palisade grass found that steers offered a 25-cm pre-grazing sward height consumed substantially more forage dry matter (about 1.86% of body weight) than steers offered a taller 35-cm sward (about 1.32% of body weight).4Journal of Animal Science. Beef cattle responses to pre-grazing sward height and low level of energy supplementation on tropical pastures That finding might seem counterintuitive, since taller grass means more available biomass. But the 25-cm sward had a denser, more leaf-rich canopy that let the animals take bites at a faster rate without walking as far between feeding stations. They spent less time grazing and more time resting, which in grazing science generally translates to animals that are meeting their intake needs more easily.
The same study found that providing a small energy supplement (at 0.3% of body weight) actually reduced forage intake without improving total digestible intake, a substitution effect where the supplement partly replaced grass rather than adding to the animal’s total nutrition. The takeaway for ranchers is that managing sward structure through rotational grazing, keeping the canopy at a height that maximizes leaf density, can matter more than supplementation strategies for overall intake.
Seed Dormancy and Establishment Challenges
Getting palisade grass established from seed is trickier than for many crop species because of the grass’s naturally high seed dormancy. Freshly harvested seeds often germinate poorly, even under ideal conditions, because of physical and physiological dormancy mechanisms built into the seed coat and embryo. Research on controlled storage has shown that dormancy can be broken over time, with warmer storage temperatures accelerating the process, though high temperatures also gradually degrade seed viability.5Seed Science and Technology. Performance of tropical forage grass (Brachiaria brizantha) dormant seeds under controlled storage In that work, the best germination results came from seeds stored at moderately elevated temperatures (around 40-50°C), where dormancy release outpaced viability loss over the storage period. Acid scarification of the seed coat also improved germination, confirming that the physical barrier of the seed coat is part of the dormancy mechanism.
In practice, seed producers typically store palisade grass seed for several months after harvest before selling it, because fresh seed simply will not germinate well enough for reliable pasture establishment. Farmers who try to plant freshly harvested seed often get patchy, disappointing stands. Understanding this dormancy biology is also relevant for seed quality testing, since standard germination tests on fresh seed can dramatically underestimate the eventual germination potential.
Breeding Through Apomixis
Palisade grass reproduces primarily through apomixis, a form of asexual seed production in which the embryo develops from the mother plant’s cells without fertilization. This means that seeds from an apomictic plant are genetic clones of the mother. From a cultivar perspective, apomixis is both a blessing and a complication. It is a blessing because any superior genotype can be immediately fixed as a cultivar, with every seed producing an identical plant, and there is no genetic segregation across generations. The cultivar stays true to type indefinitely.
The complication arises for breeders who want to create new varieties through hybridization. Because the commercially important palisade grass types are apomictic, they cannot easily be used as the female parent in a cross. Artificial hybridization of brachiariagrasses became possible only after researchers developed a sexual tetraploidized form of the related ruzigrass (Brachiaria ruziziensis) in the late 1980s.6Crop Science. Apomixis for Cultivar Development in Tropical Forage Grasses By crossing this sexual tetraploid with pollen from apomictic species, breeders could generate segregating hybrid populations and then select among the progeny for desirable traits. The apomictic offspring from such crosses are immediately fixable as new cultivars. This breeding strategy has produced most of the newer palisade grass cultivars released in the last two decades.
Making Silage From Palisade Grass
Tropical grasses are notoriously difficult to ensile compared to temperate forages like corn or ryegrass. The main problem is that tropical grasses typically have lower concentrations of soluble carbohydrates (the sugars that lactic acid bacteria need to drive fermentation) and higher moisture content, which together create conditions favorable for undesirable fermentation by clostridia. Palisade grass is no exception, and ensiling it without additives tends to produce silage with high pH, elevated ammonia nitrogen, and poor stability.
Research has explored several strategies to improve the outcome. Adding citrus pulp at ensiling increases the dry matter content and provides fermentable carbohydrates that promote better lactic acid production.7Acta Scientiarum. Animal Sciences. Additives in ensiling palisade grass managed under grazing intensities Mixing palisade grass with legumes before ensiling is another approach that has shown promise. When forage peanut (Arachis pintoi) was added to palisade grass at ensiling, the chemical composition and fermentation profile of the resulting silage improved, with higher lactic acid concentrations and larger lactic acid bacteria populations.8Tropical Grasslands-Forrajes Tropicales. Chemical composition, fermentation profile, microbial population and dry matter recovery of silages from mixtures of palisade grass and forage peanut Similarly, mixing palisade grass with stylo (Stylosanthes spp.) raised the crude protein content of the silage while lowering pH and ammonia concentrations, markers of better-quality fermentation, as the proportion of stylo increased.9PubMed. Nutritive value and fermentation quality of palisadegrass and stylo mixed silages
The common thread in all these silage strategies is that pure palisade grass silage is generally mediocre, but blending with legumes or adding carbohydrate-rich supplements can produce a feed that is both more nutritious and better preserved. For livestock operations that need to stockpile feed for the dry season, this matters a great deal.
Intercropping With Soybean
One of the more economically interesting uses of palisade grass is in integrated crop-livestock systems, where the grass is intercropped with row crops like soybean. In a no-till system, soybean and palisade grass sown simultaneously yielded about 3.28 Mg per hectare of soybean seed, which was comparable to the 3.50 Mg per hectare from monocrop soybean.10European Journal of Agronomy. Intercropping soybean and palisade grass for enhanced land use efficiency and revenue in a no till system When palisade grass was sown at the same time as soybean or within 30 days of soybean emergence, the first-cut forage dry matter production from the grass was higher than when the grass was planted later. The net result was that the intercropping system generated roughly 1.6 times more revenue than soybean alone, because farmers harvested a soybean crop and then had an established pasture producing forage afterward.
This kind of system is increasingly important in tropical agriculture because it provides ground cover after the soybean harvest, reduces erosion, suppresses weeds, and feeds livestock during the off-season. The palisade grass root system also contributes to soil structure over time, a benefit that carries over to the next cropping cycle.
Soil Health and Root Effects
Palisade grass has a deep, aggressive root system that penetrates compacted soil layers effectively. After the roots decompose, they leave channels in the soil that improve aeration and water permeability, reducing the negative effects of compaction on subsequent crops.11Ciência e Agrotecnologia. Previous cultivation of palisade grass and soil correctives: influence on growth and yield of soybean cultivated under various soil compaction levels For this reason, palisade grass is sometimes grown specifically as a rotation crop to rehabilitate degraded or compacted soils before planting soybean, corn, or other cash crops. The grass root channels allow the next crop’s roots to develop more fully, which in turn supports better shoot growth and yield.
The grass also influences soil microbial communities involved in nutrient cycling. When compared with ruzigrass and Guinea grass in a study of nitrogen-cycling microorganisms, palisade grass supported lower soil nitrification potential than ruzigrass.12SpringerLink / Archives of Microbiology. Microbial N-cycling gene abundance is affected by cover crop specie and development stage in an integrated cropping system Lower nitrification can be beneficial in tropical systems because it slows the conversion of ammonium to nitrate, and nitrate is far more easily leached out of the soil by heavy rainfall. In other words, palisade grass may help keep nitrogen in the root zone longer, though this is an area where the research is still developing and the practical significance depends heavily on local soil and climate conditions.
The Spittlebug Resistance Gap
While Marandu’s resistance to spittlebug nymphs was the trait that launched its mass adoption, that resistance story is more nuanced than it first appears. Spittlebugs have two feeding stages that damage plants: the nymphal stage, when they feed on roots and the base of the plant inside a protective foam mass, and the adult stage, when they feed on leaves and stems. Research testing 164 hybrid genotypes against three spittlebug species found that most hybrids were classified as resistant to nymphs, but the average adult damage score of those same hybrids was no different from susceptible control plants.13Oxford Academic (Journal of Economic Entomology). Independence of Resistance in Brachiaria spp. to Nymphs or to Adult Spittlebugs (Hemiptera: Cercopidae): Implications for Breeding for Resistance The correlations between nymph survival and adult damage were extremely low, indicating that resistance to the two life stages operates through largely independent mechanisms.
This finding has real consequences for breeding programs. Selecting a plant that shrugs off nymphs does not automatically produce a plant that resists adult feeding damage. Breeders need to screen separately for both traits, which doubles the evaluation workload. It also means that existing cultivars selected primarily for nymphal resistance may still suffer significant damage from adult spittlebugs in years when populations are high, a vulnerability that farmers sometimes discover the hard way.
Invasiveness Outside Managed Pastures
Palisade grass was introduced to the Americas as a deliberate forage planting, but its aggressive growth and prolific seed production make it a potential invasive species in natural ecosystems. In the Brazilian Cerrado, one of the world’s most biodiverse savannas, escaped palisade grass can invade native grasslands, compete with native plant species for light and resources, and alter fire regimes by producing dense fuel loads. The same traits that make it an excellent pasture grass, rapid establishment, shade tolerance once mature, dense root systems, also make it a formidable competitor in unmanaged landscapes.
Conservationists in Brazil and other tropical countries have flagged Urochloa species as a significant threat to biodiversity in savanna and cerrado remnants. The grass is not easily controlled once established in native vegetation, because its root system resists removal and its seed bank persists in the soil. For landowners adjacent to protected areas, managing palisade grass to prevent escape into natural ecosystems is an ongoing responsibility that adds a layer of complexity to what otherwise looks like a straightforward agronomic choice.
Water Stress Responses Up Close
The leaf-level changes that palisade grass undergoes during drought deserve a closer look because they reveal both the grass’s strengths and its limits. Under reduced soil moisture, the vascular bundle sheath, the ring of cells surrounding each vein that plays a central role in C4 photosynthesis, showed no significant change in thickness, even as surrounding tissues shrank.14SciELO / Revista Ceres. Anatomical adaptations to different soil moisture contents in palisade grass and smooth pigweed Maintaining the bundle sheath is important because it is where carbon fixation is concentrated in C4 plants, so preserving its structure helps sustain photosynthesis during moderate drought. However, the researchers noted that this pattern, where bundle sheath cells remain stable while other tissues adjust, is similar to what is seen in plants with low drought tolerance rather than in highly drought-adapted species. Palisade grass copes with moderate water deficit, but it is not a desert grass, and prolonged severe drought will kill stands or reduce them to bare stubble that recovers slowly.
This matters for ranchers operating in areas with unpredictable rainfall. Palisade grass can handle a normal dry season in the Cerrado or similar climates, but it is not a safe bet in semi-arid regions or during extreme drought years. In those situations, more drought-tolerant species or cultivars bred specifically for drier conditions may be a better choice.
The Economics of Tropical Pasture Decisions
Choosing a pasture grass in the tropics involves tradeoffs that rarely get simple answers. Palisade grass offers good all-around performance, reliable spittlebug nymph resistance, compatibility with intercropping systems, and soil health benefits when used in rotation. Against that, it demands attention to sward management to maximize animal intake, responds dramatically to nitrogen fertilization that many producers cannot afford, makes mediocre silage without additives, and carries invasiveness risks near natural ecosystems. Its seed dormancy complicates establishment, and its resistance to adult spittlebugs is weaker than its resistance to nymphs.
For many tropical livestock producers, palisade grass remains the default because no other single species matches its combination of adaptability and yield. But the research consistently shows that the grass rewards active management, whether through fertilization, controlled grazing height, intercropping with legumes, or strategic ensiling with additives. Treated as a low-input, plant-it-and-forget-it grass, it still functions, but it delivers a fraction of what it is capable of when managed well.