Antelope grass growing on the side of the road
Antelope grass growing on the side of the road
Botanical Name:
Echinochloa pyramidalis (Lam.) Hitchc. & Chase. [Poaceae]
Common names
Antelope grass, limpopo grass, pasto limpago, sil grass (Ecoport, 2010; USDA, 2010)
Synonyms
Echinochloa holubii (Stapf) Stapf, Panicum holubii Stapf, Panicum pyramidale Lam., Panicum quadrifarium Hochst. ex A. Rich.
Description
Antelope grass (Echinochloa pyramidalis (Lam.) Hitchc. & Chase.) is a tall perennial grass, usually 1.8-2.4 m high but occasionally reaching 3.4-4.5 m. Culms are reed-like: erect or geniculate, with roots growing out from the lower nodes. Leaves are blade-shaped, stiff, expanded or folded, 8–60 cm long x 2–25 mm wide. Leaf sheaths can be hairy or glabrous. Inflorescences are racemes (3-20 cm long) borne along a central axis (8-40 cm long). Spikelet packing is irregular, 4- to 6-rowed. Spikelets are acute, awnless 3-4 mm long . It has a very strong fasciculated root system that is able to spread quickly into the soil profile.
The grain is used as human food in some parts of Africa . It is mainly grown for fodder in pure and dense stands with a leafy table at 1.2-2 m. Yields may reach up to 25 t/ha of green matter per cutting. It is relished by livestock and able to withstand heavy grazing . It starts growing during the rainy season but it is also a good source of fresh fodder during dry season since it is able to regrow quickly and vigorously after dry season fires, even in very dry conditions. Types with glabrous leaf sheath may also be used for hay.
Distribution
Antelope grass is native to tropical Africa, Southern Africa and Madagascar. It grows in swampy areas, seasonally flooded areas, wet clay soils, alongside water and in floating meadows . It is a highly productive C4 plant with an optimum growth temperature above 30°C.
It grows best at altitudes ranging from sea-level to 300-1500 m, on badly drained black clays of alluvial nature and alkaline soils. It is well suited to clayey depressions that are periodically flooded. Antelope grass is frost sensitive . It can withstand long periods of drought and grow in dry lands with satisfactory productions .
Forage management
Echinochloa pyramidalis can achieve DM yields of 15.3 t DM/ha/year in 12 cuts when grown in permanently flooded mangrove areas . In Guyana, DM production increased from 21.3 t DM/ha to 27.6 t/DM ha from 21 and 35 days. Phosphorus fertilization can increase yields. In a semi-arid climate, harvest at 42 days gave better quality hay than at 56 to 98 days . In the Amazon Basin and under rotational grazing, much lower yields of 0.39-0.76 t/ha were obtained (12-day grazing and 40-day rest period), with a 50% decrease between the 1st and 4th cut, suggesting that this type of management is inadequate. In order to maximise forage use efficiency and to prevent losses due to leaf senescence, a 25-day regrowth interval has been recommended, as leaf senescence increases strongly after 25 days.
Environmental impact
Thanks to its dense, tangled, floating stems that root at the nodes, antelope grass can have a protective effect against wave action on the walls of earth dams and flood-induced erosion of river banks .
It has also recently be tested in sludge dewatering beds. Increasing concentrations of faecal sludge had a positive effect on the sturdiness and productivity of Echinochloa pyramidalis: it yielded 150 DM t/ha/year of above-ground biomass, and 30 DM t/ha/year of below-ground biomass . Echinochloa pyramidalis was able to remove 50%-80% of nutrients in distillery wastewater .
In some humid contexts Echinochloa pyramidalis is considered one of the most troublesome weeds, e. g. in the aquatic system of the Guyana Sugar Corporation or in the freshwater wetlands of the Mexican tropics. This alien species reduces biodiversity by replacing native species. To eliminate this species completely, it is necessary to recreate the natural topography and hydrology of the wetland and to select control mechanisms that disrupt those growth characteristics (e.g., rapid propagation from rhizomes and horizontal expansion via tillers) that make this grass more competitive than native species.
Caution
No toxicity of this plant has been reported .
Ruminants
Echinochloa pyramidalis is particularly rich and it used as hay and silage very useful in certain region, and is an excellent dry-season grazing after burning of waste biomass . Although very coarse, native animals graze it easily at ground level at the end of the dry season. It is of great value as deferred feed for cattle, sheep and goats throughout tropical Africa .
Chemical composition and nutritive value
Echinochloa pyramidalis has a variable composition that depends on the season and age at regrowth. The average crude protein on 27 samples was 7.2 % DM (± 3.9), but much higher values have been reported, such as 15 % or 20 %. At 6 week, the crude protein and the content in structural and non-structural carbohydrate were respectively 9,8%, 44,3% and 51,2 % DM . Crude protein content, N, P K and Na, Fe, Zn and Cu were higher during periods of rainfall, while the Ca, Mg, S, Mn and B were higher in the less rainy season. Sulfur is the only element that is below the ideal level for the nutrition of cattle (0.2 to 0.5 g/kg) .
The crude protein content of hay decreased from 6.6 % to 4.7 % between 42 days and 98 days (56, 70, 84 and 98 days) .
Palatability
Echinochloa pyramidalis is highly palatable, especially in early growth, and was among the most palatable (with Digitaria eriantha) of 15 species evaluated for their feeding potential in Venezuela . It becomes less palatable at later stages of regrowth, even at the early flowering stage.
Cattle
In Guyana, heifers grazing antelope grass had a daily weight gain of 300 g/day and 754 g/ha at an optimum stocking rate of 1.6 head/ha. Pasture containing Echinochloa pyramidalis, Cynodon dactylon, Digitaria eriantha and Digitaria swazilandensis, with a 28-day (or less) grazing, was able to maintaining up to 5 cows/ha/year .
Sheep
Black Belly sheep fed chopped Echinochloa pyramidalis for 3 years (4.5 kg/ewe/day supplmented with rice bran, wheat middlings and copra meal) had satisfactory reproductive performances : 40 % ewes lambed once per year, 52 % ewes had 2 lambs per litter and lambing percentage was 139%. Lambs weaned per ewe mated was 98.9%; birth weight was 1.8 kg and weaning rate was 73.1% .
Goats
Goats could be maintained on 6-week old Echinochloa pyramidalis, as it was better ingested than 3, 9 or 12-week old grass. At 6 weeks, the daily digestible DM intake was 30 MJ/kg W0.75, DE intake was 0.60 MJ/kg W0.75 and nitrogen retention was 0.1 g/kg W0.75.
