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Graminae
Synonyms
Eriochloa polystachya Kunth.
Common names
Janeiro (Costa Rica), carib grass (United States), malojilla
(Fiji), hierba del Caribe (Cuba).
Description
A glabrous, branching perennial, ascending from a decumbent
base, commonly 1 m or more tall, with flat blades 10-15 mm wide and several
to many narrowly ascending racemes (Hitchcock, 1927). Spikelets silvery,
3-4 mm long. Grain oblong, free within the hardened glume and palea (Cooke,
1958). It differs from Para grass in many ways: carib grass blooms throughout
the year in the southern United States, whereas Para grass blooms from
September to January; secondary racemes of Para are abundant, those of
carib are sparse and the spikelets nearly sessile; carib grass has darker
green, more glabrous, shorter and narrower leaves than those of Para; the
flower stalks of carib grass are 15-30 cm shorter than those of Para, with
stolons approximately 1 m long; carib grass is densely covered with hairs
on the nodes and sparsely on the leaf-sheaths and on the nodes; carib grass
is more palatable than Para grass (Judd, 1979).
Distribution
Native of the Caribbean region from the West Indies to Brazil.
Altitude range
Sea-level to 1 800 m. It grows best at 1 500 m in Costa Rica;
at higher elevations production declines.
Rainfall requirements
Like Para grass, it is adapted to a hot, humid climate (Gonzalez
& Pacheco, 1970). In Puerto Rico it grows in a rainfall range of 1
500-2 000 mm of evenly distributed rainfall.
Drought tolerance
It has little drought tolerance.
Soil requirements
It adapts to a wide variety of soils but prefers fertile, moist
sandy loams. In poor, dry soils it is short-lived, produces little and
is invaded by weeds. Selection 6017 tolerates acid soils, high in iron
and aluminium, in Colombia (CIAT, 1978) and Puerto Rico (Vicente-Chandler
et al., 1974).
Land preparation for establishment
A good seed-bed is required.
Sowing methods
Propagated vegetatively by stem cuttings or division of root-
stocks, in furrows 1 m apart.
Sowing depth and cover
Sow the cuttings 15-20 cm deep and cover with 5-7.5 cm of soil.
Sowing time and rate
Use 1 500 kg of mature cuttings per hectare in summer.
Tolerance to herbicides
Carib grass can be eradicated by applying 6.5 kg of dalapon
(2,2 dichloropropionic acid) in 1 100 litres of water per hectare and repeating
the application three weeks later if necessary (Vicente-Chandler et al.,
1974).
Response to defoliation
Heavily fertilized carib grass in Puerto Rico gave highest
yields when cut at 90-day intervals producing 117 264 kg green forage per
hectare per year, and 113 120 kg cut at 60-day intervals.
Grazing management
The grass should be renovated when needed and irrigated during
the dry season. Put the cattle in to graze when the grass reaches 0.5-0.6
m in height and graze only once. It is usually cut for green chop.
Dry-matter and green-matter
yields
It yields 175 t/ha of green material in Costa Rica of 19 percent
dry matter and 1.6 percent crude protein (Gonzalez & Pacheco, 1970).
Suitability for hay and
silage
It makes palatable hay. Medling (1972) made good silage in
plastic bags at Gualaca, Panama when 10 percent molasses was added.
Cultivars
Burkart (1969) records three forms forma intermedia,
var. montevidensis and var. parodi.
Diseases
Carib grass is attacked by a rust, Uromyces leptodermus, which
causes minor defoliation during dry periods, but is of little importance.
It is unaffected by pangola rust (Puccinia oahuensis) or grey leaf spot
(Piricularia grisea).
Latitudinal limits
About 24°N to 20°S.
Ability to compete with
weeds
Its vigorous growth suppresses weeds.
Palatability
It is quite a palatable grass.
Chemical analysis and
digestibility
In Costa Rica analysis of material at floral initiation revealed
6.08 percent crude protein, 29.66 percent crude fibre, 42.82 percent nitrogen-free
extract, 1.35 percent ether extract and 10.09 percent ash on a 10 percent
moisture basis (Gonzalez & Pacheco, 1970). It has high protein in Suriname
(Dirven ,1963b) with a range of 5.6-10.3 percent, an average of 7.5 percent
of the dry matter. Protein content increased from 6.4 percent when no nitrogen
was applied to 10.2 percent with 880 kg N/ha in Puerto Rico (Vicente- Chandler
et al., 1974).
Natural habitat
Moist places.
Tolerance to flooding
Selection 6017 withstands flooding in Colombia (CIAT, 1978).
Fertilizer requirements
It stands heavy, complete fertilizer application. Liming is
needed with the acid ultisol soils and in Puerto Rico from 2 5004 500 kg/ha
are applied to bring the soil up to 70 percent base saturation. Two weeks
after planting some 325 kg/ha of a 15:5:10 fertilizer mixture is applied
and again three months later for intensive grazing. Yields increase linearly
with nitrogen applications up to 440 kg/ha and more slowly to 880 kg/ha,
and 1 760 kg/ha.
Genetics and reproduction
2n=36 (Fedorov, 1974).
Seed production and harvesting
The seed is rarely viable and the grass is propagated vegetatively.
Animal production
Figures for Carib grass production in Puerto Rico show that
with a rainfall of 1 500-2 000 mm per year, evenly distributed, Carib grass
fertilized with 5 t/ha annually of 15:5:10 fertilizer and cut every 40-60
days can support 7.75 steers of 270 kg each per hectare per year (Vicente-Chandler
et al., 1974).
Further reading
Gonzalez & Pacheco, 1970; Vicente-Chandler et al., 1974.
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