Brachiaria mutica


Scientific name

Brachiaria mutica (Forssk.) Stapf

Synonyms

Urochloa mutica (Forssk.) T.Q. Nguyen
Panicum barbinode Trin.
Panicum muticum Forssk. [basionym]
Panicum purpurascens Raddi

Family/tribe

Family: Poaceae (alt. Gramineae) subfamily: Panicoideae tribe: Paniceae.

Common names

para grass (Africa, Australia, USA);  buffalo grass, Dutch grass, giant couch, Scotch grass;  Mauritius signal grass (South Africa);  angola, pasto Pará, hierba de Pará, papare and malojilla (South America);  gramalote (Peru);  parana (Cuba);  herbe de Para (French).

Morphological description

A creeping perennial grass with long, coarse stolons up to 5.0 m, very hairy, decumbent stems and soft, moderately hairy leaves up to 20 mm wide and 30 cm long.  Leaf sheath has a densely hairy collar.  Inflorescence is a panicle 6–30 cm long, comprising 5–20 densely flowered racemes 2–15 cm long, with paired spikelets 2.5–5.0 mm long in several uneven rows.
Stolons and branches root readily at the nodes.

Distribution

Native to:
Probably native to flood plains of sub-Saharan tropical Africa.

Introduced pan-tropically as a pasture grass of seasonally inundated or high rainfall environments.

Uses/applications

Planted for grazing in flat, poorly drained or high rainfall environments.  Also used as a cut-and-carry forage.  Can be cut for hay but is generally slow to dry in the humid environments where it grows productively.
Rested wetland areas can be used a dry season reserves of green feed.  A similar system uses shallow water ponding on the edges of which para grass continues to grow as the water recedes.  Para will grow in water to 1.2 m deep in the tropics.

Ecology

Soil requirements

Well adapted to a wide range of soil types (from sandy to clay soils) of moderate to good fertility.  Suited to poorly drained (swampy or seasonally waterlogged) land in the tropics and warmer subtropics, but will also grow productively on free-draining soils in high rainfall environments.  Tolerates moderate salinity, low pH to 4.5 and high levels of trace elements normally produced under water-logged conditions.

Moisture

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Humid to sub-humid regions with 1,200–4,000 mm annual rainfall.  Will also grow in swampy areas of drier environments down to 900 mm annual rainfall, but will not tolerate extended dry conditions.  Para grass will stand long-term flooding.  Tolerance of depth of water is probably related to water temperature, as para grass tolerates depths of up to 1.2 m in the tropics but only up to 30 cm depth in the subtropics.  Hairy leaves and long hollow stems will float on water, but roots cannot tolerate continuous submergence.  Develops adventitious rootlets under flooded conditions.

Temperature

Warm season growth only, with growth restricted by temperatures below 15ºC.  Very frost sensitive.  Leaf is killed by frost but plants can recover.

Light

Moderately tolerant of shade but prefers full sun.  Lower shade tolerance than signal grass (B. decumbens ).  Grown under extensive areas of mature coconuts in the Philippines but prone to weed invasion.

Reproductive development

Reproductive development of para grass is poorly understood.  Reported to be a short-day species that flowers most prolifically in humid environments at latitudes of 10–20º.  Dry conditions may stimulate flowering in the subsequent wet season.  Adequate soil N may also stimulate flowering and seed set.  Little or no flowering is reported at subtropical latitudes.  In northern Australia, para grass flowers in late April/early May and sets seed in May.

Defoliation

Under constant heavy defoliation the sward of the palatable para may become very open and subject to invading species.  These include broadleaf weeds and sedges, especially Cyperus aromaticus (Navua sedge) in Fiji and Sida spp. elsewhere on better drained soils.
Sward height should be maintained at >20 cm to prevent weed ingress.  Moderate grazing pressure may be required to reduce seed set and maintain forage quality in highly productive environments.

Fire

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Para grass can be burnt in the dry season and will recover.  It is this ability to produce a bulk of fuel in the wet season when not grazed, together with subsequent hot fires that has caused para grass to be regarded as an environmental weed in ungrazed wetland environments in some countries.

Agronomy

Establishment

Easily established from vegetative sets hand-planted or disc-harrowed to a depth of 10–15 cm.  Plant sets should be 25–30 cm long with 3–4 nodes, and at least 2 nodes should be buried into moist soil.  Established plants root readily at the nodes.  Can also be sown from seed at a rate of 3–4 kg/ha, but seed is not generally available.

Fertiliser

Responds well to nitrogen fertiliser under its moist growing conditions.  DM productivity can be sustained by the addition of companion legumes contributing 20–30% of DM.

Compatibility (with other species)

In ponded pasture systems in seasonally dry northern Australia, para has been grown with grasses that can grow in water to 1.2 m deep;  these include aleman grass (Echinochloa polystachya ) cv. Amity and hymenachne (Hymenachne amplexicaulis ) cv. Olive.  Despite their successful animal production, these ‘water’ grasses are now regarded as environmental weed because they are capable of invading wetlands.

Companion species

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Grasses:  Echinochloa polystachya , Hymenachne amplexicaulis .
Legumes:  Macroptilium lathyroides , Aeschynomene americana .  On free-draining soils;  Pueraria phaseoloides , Centrosema molle , Neonotonia wightii Calopogonium mucunoides may persist because of its low palatablity.

Pests and diseases

A sap-sucking leafhopper can attack para grass in Fiji.  Coccid bug attack associated with sooty mould fungus (Capnodium sp.) can damage young leafy shoots.  Pastures can suffer severe attacks from the striped grass worm (Mocis latipes).  Blast (Piricularia sp.) and sheath blight (Rhizoctonia sp.) occur in Thailand.
Seed heads can be attacked by smut (possibly Tilletia ayresii).

Ability to spread

Spreads rapidly (up to 5 m in a year) into suitably moist soils through its long stolons and possibly through water-borne seed.  Para grass has spread throughout the humid tropics following introduction as a pasture grass .

Weed potential

Para grass can become a problem in wetland areas that are not grazed - sugarcane fields, irrigation ditches and drains.  It is now regarded as an environmental weed in northern Australia due to its ability to carry hot fires in seasonally dry and ungrazed wetlands (including national parks);  these fires can kill natural stands of Melaleuca trees.  It can also invade natural waterways, displacing native grasses whose seed provides food for indigenous birds (e.g. wild rice - Oryza australiensis).

Feeding value

Nutritive value

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A grass of high nutritive value, although DM intake by grazing stock may be reduced by high water content, including droplets of water held on the hairy leaves and stems.  Actively growing para grass can have very high nutritive value, with 14–20% CP, and IVDMD of 65–80% for leafy regrowth and 55–65% IVDMD for whole top growth.  Quality declines with maturity to 35–45% IVDMD for tops.

Palatability/acceptability

Leaf is highly palatable and selectively grazed.  Mature stolons and stems are much less palatable but will be consumed by grazing cattle if no alternative feed is available.

Toxicity

No reports of toxicity to ruminant livestock were cited.

Production potential

Dry matter

DM yields of up to 30 t/ha/year have been recorded for fertilised para, but more generally 5–12 t/ha/year.  In humid-tropical Vanuatu, presentation yields were maintained between 2 and 4 t/ha for unfertilised para grass -puero (Pueraria phaseoloides ) pastures grazed at 3 head/ha over a 3-year period.

Animal production

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Under wetland or irrigated conditions, liveweight gains of 300–800 kg/ha/year have been recorded with steers gaining between 0.8 and 1.0 kg/hd/day under stocking rates up to 3 beasts per hectare.
In humid-tropical Vanuatu, steers grazing pure para grass pastures gained 511 kg/ha/year liveweight, averaging 0.55 kg/head/day over a 3-year period, whereas cattle grazing para grass/legume pastures produced 621 kg/ha/year liveweight and averaged 0.65 kg/head/day over the same period.  In the Philippines, local cattle grazing para grass at 2 head/ha gained 0.43 kg/head/day.  In subtropical, coastal Australia, irrigated para grass -centro (Centrosema molle ) pastures supported steer liveweight gains of 0.96 kg/head/day.

Genetics/breeding

Reproduction is generally by vegetative means, although para grass will flower and produce seed in humid, low latitude environments.  Seed production is commonly apomictic, so that little genetic variation is thought to exist within the species.  Very poorly represented in the major tropical forage germplasm banks and no breeding programs have been undertaken.

Seed production

Seed yields are low with yields of 10–30 kg/ha from mechanical or hand harvest.  Mechanical harvesting may be complicated by bogging of machinery in highly productive environments.  Para grass will not flower at subtropical latitudes (see section on reproductive development).

Herbicide effects

Para grass as a weed in ditches can be easily controlled with herbicides such as glyphosate (720 g a.i. in 200 l/ha water).

Strengths

  • Adapted to swampy, flooded areas.
  • Supports moderately high levels of ruminant production.
  • Rapid spread from stolons.
  • Young leaves very palatable.

Limitations

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  • Poor drought tolerance.
  • Cold-sensitive.
  • Poor legume compatibility.
  • Potential weed if ungrazed.

Other comments

Somewhat similar to tanner grass (Brachiaria arrecta ), but tanner grass has single, rather than paired spikelets.

Selected references

Mullen, B.F. and MacFarlane, D.C. (1998) The effect of band-seeding legumes into para grass (Brachiaria mutica ) on pasture production, sustainability and animal productivity in Vanuatu. Tropical Grasslands, 32, 34–40.
Schultze-Kraft, R. and Teitzel, J.K. (1992) Brachiaria mutica (Forssk.) Stapf. In: t’Mannetje, L. and Jones, R.M. (eds). Plant Resources of South-East Asia No. 4. Forages. pp. 64–65. (Pudoc Scientific Publishers, Wageningen, the Netherlands).
Shiva Dhar, Gupta, S.D., Singh, A. and Arya, R.L. (2001) Performance of grasses with cutting management under seasonal waterlogged conditions. Indian Journal of Agricultural Sciences, 71, 698–700.
Tiwari, C.M., Tiwari, D.P. and Jain, R.K. (2001) Nutritional evaluation of para grass (Brachiaria mutica ) in goats. Cheiron, 30, 38–39.
Xavier, D.F., Carvalho, M.M. and Botrel, M.A. (2002) Characteristics and potentials of Brachiaria pastures for milk production. Características e potencialidades de pastagens de braquiárias para produção de leite. Documentos - Embrapa Gado de Leite (No. 87).

Internet links

Cultivars

Cultivars

Country/date released

Details

'Comum' Brazil   
'Fino' Brazil   
'Lopori' Zaire High yielding type recommended in Zaire.
'Parana' Cuba (Brachiaria purpurescens)
'Aguada' Cuba   

Promising accessions

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Promising accessions

Country

Details

None reported.