Brachiaria brizantha (A. Rich.) Stapf

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Graminae

Common names

Palisade grass (Samoa), signal grass (East Africa), St Lucia grass (Queensland), Ceylon sheep grass (Sri Lanka), upright brachiaria (Zimbabwe), bread grass (South Africa), estrella de Africa, pasto alambe (Latin America).

Description

Perennial up to 120 cm high, with stout erect culms and broadly lanceolate leaf-blades. Two to five racemes, up to 15 cm long, with two rows of almost sessile, overlapping, rounded spikelets, 4-6 mm long on the underside. It differs from B. decumbens in that the spikelets have a sub-apical fringe of long purplish hairs, and the spikelets are longer than those of B. decumbens.

Distribution

Native to tropical Africa but now introduced into most tropical countries.

Season of growth

Spring to autumn.

Altitude range

Sea-level to 3 000 m.

Rainfall requirements

It requires a rainfall generally in excess of 500 mm.

Soil requirements

It tolerates a wide range of soils and is tolerant of acid conditions.

Ability to spread naturally

It can spread slowly by seed as the seed ages to break its dormancy.

Land preparation for establishment

A well-prepared seed-bed is preferable.

Sowing methods

It can be propagated vegetatively by sods, root pieces and stems.

Response to defoliation

It will stand heavy grazing. In Sri Lanka, Sivalingam (1964) recommended a cutting interval of 30 days when fertilized with nitrogen at 0, 45, 132 and 396 kg/ha.

Grazing management

It can be heavily grazed if used as a monospecific sward and regularly fertilized with nitrogen. If grown with a legume the grazing system must favour the legume and adequate phosphorus must be maintained.

Response to fire

B. brizantha will not tolerate fire. In Zambia annual burning of dominantly Hyparrhenia grassland for three years reduced the B. brizantha cover from 0.38 to 0.09 percent (Brockington, 1961). Selection 665 at CIAT, Quilichao, Colombia has good resistance to burning, but burning is not recommended (CIAT, 1978).

Dry-matter and green-matter yields

With Alysicarpus vaginalis, fertilized with 88 kg N and 88 kg P2O5/ha it yielded 6 750 kg DM/ha from three cuts (Fernando, 1961). In Fiji over a three-year period it yielded an average of 7 850 kg DM/ha with a crude protein content of 7.6 percent (Roberts, 1970). It yielded 16 800 kg/ha green matter in Tanzania. In Sri Lanka B. brizantha gave herbage dry-matter yields per year ranging from 10 368 to 17 377 kg/ha at nitrogen applications ranging from 56 to 280 kg/ha (Appadurai, 1975).

Suitability for hay and silage

In the United Republic of Tanzania it has made useful silage (van Rensburg, 1952) and in Sri Lanka it is useful both for hay and silage (Bor, 1960). In Burundi a mixture of Eragrostis curvula (at least 50 percent), B. brizantha and Setaria sphacelata is recommended for silage (Scaillet, 1965).

Toxicity

At the Queensland Agricultural College, Lawes, Queensland, Australia, crossbred wether sheep grazing on a vigorous sward of Brachiaria brizantha growing on a black clay soil developed severe photosensitization and icterus, marked by drooping ears, swelling of the subcutis of the face and eyelids, and congested, yellowish mucous membranes. The sheep rapidly lost condition and died. In these animals the skin over the muzzle, ears, and eyelids was necrotic and the conjunctival sac filled with purulent exudate with consequent blindness (Briton & Paltridge, 1941).

Main attributes

Its productiveness, drought resistance, ability to spread and suppress weeds and its ability to grow in shade.

Main deficiencies

Its tendency to produce monospecific swards. Its low seed production.

Optimum temperature for growth

About 30-35°C.

Minimum temperature for growth

It grows well into the winter, being green when other tropical grasses are brown and dry.

Frost tolerance

It will survive frosts.

Latitudinal limits

It can be used in pastures at high altitudes in Burundi (Scaillet, 1965).

Response to light

It tolerates shade under coconuts well in Sri Lanka (Bor, 1960).

Pests

It is attacked by some insect pests.

Palatability

It is very palatable, with a good leaf/stem ratio.

Chemical analysis and digestibility

It has good nutritional value. Göhl's (1975).

Natural habitat

Grassland valleys and open woodlands.

Tolerance to flooding

It will not tolerate flooding (Bor, 1960; CIAT, 1978).

Fertilizer requirements

It performs quite well without fertilizer and was found to be one of the best grasses (B. brizantha 665) under low nitrogen and low phosphorus at CIAT, Quilichao, Colombia. However, it responds well to fertilizer, producing over 4 000 kg DM/ha with no nitrogen but adequate phosphorus, and high yields with complete fertilizer.

Compatibility with other grasses and legumes

In Sri Lanka, Fernando (1961) grew it in association with Alysicarpus vaginalis and Centrosema pubescens. High nitrogen applications decreased the proportion of legumes, while phosphorus applications increased the proportion. In Malaysia Stylosanthes guianensis and centro have been successful (Vendargon, 1964). However, if fertilizer mixtures are not balanced in favour of legumes the grass will dominate.

Seed production and harvesting

Selection 665 at CIAT, Colombia has good seed production. Seed remains viable for about three years (Jones, 1973).

Economics

B. brizantha has shown to be an outstanding pasture for leys in Kenya (Bogdan, 1959), Madagascar (Birie-Habas, 1959; Granier & Lahore, 1961), the United Republic of Tanzania, Fiji (Payne et al., 1955), Sri Lanka (Panabokke, 1959), Nigeria (Foster & Munday, 1961), Uganda (Bredon & Horrell, 1962), Burundi, Zaire (Scaillet, 1965) and other countries.`

Animal production

In a grazing trial in Sri Lanka, Fernando (1961) obtained a live- weight gain of 464 kg/ha from grass alone, 647 kg/ha from a Pueraria phaseoloides/Brachiaria brizantha sward and 631 kg/ha from a Centrosema pubescens/B. brizantha mixture over a 260-day season.

Links for the genus:

Further reading

Fernando, 1961.

Value for erosion control

It has been used successfully in Australia (Queensland) and India (Gandhi, 1957; Patil & Ghosh, 1963).

Tolerance to drought

It is fairly drought tolerant (Bor, 1960; CIAT, 1978).

Disease resistance

Good.