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Graminae
Synonyms
Tripsacum fasciculatum Trin.
Common names
Guatemala grass, zacate prodigio (Latin America).
Note
It has recently been suggested that Tripsacum laxum should be renamed Tripsacum
andersonii but as T. laxum is still common then both names are used here
Description
Culms stout, up to 3 m tall and 2.5 cm thick at base. Leaf-blades
broad (to 9 cm wide), sheaths glabrous. Racemes slender, several in a terminal
group; one male spikelet of a pair sessile, one pedicelled. It differs
from T. dactyloides in having a slender inflorescence, and the male spikelets
are 4 mm long (Gilliland et al., 1971).
Distribution
Mexico and South America; now introduced to Sri Lanka and some
other tropical countries, including Fiji.
Season of growth
Summer.
Rainfall requirements
Humid areas with rich soils, moist, but well drained.
Drought tolerance
It has poor tolerance to drought.
Soil requirements
It needs rich soil, but will tolerate acidity and aluminium.
In Suriname, it does best on podzolic soils.
Sowing methods
Established by planting stem cuttings or rooted culms at the
beginning of the rainy season, either in holes or in a plough furrow 50-65
cm apart in 1 m rows (about 10 000 per hectare; Risopoulos, 1966).
Vigour of growth and growth
rhythm
Optimum production is reached six months after planting the
cuttings, with four months between harvests.
Main attributes
Its high yield and persistence
Main deficiencies
Its poor seed production.
Chemical analysis and
digestibility
This coarse tropical grass contains less than half as much
digestible crude protein, and approximately three-quarters as much starch
equivalent, as the fine grasses of the temperate zone. Harrison (1942)
showed Guatemala grass cut at six weeks to contain 20 percent dry matter,
1.3 percent digestible crude protein and 7.9 percent starch equivalent.
Tolerance to flooding
It does not tolerate flooding.
Fertilizer requirements
Tripsacum removes 400 kg nitrogen, 80 kg phosphorus, 50 kg
potassium, 50 kg calcium and 50 kg magnesium annually per hectare of soil,
and so must be adequately fertilized (Risopoulos, 1966).
Seed production and harvesting
It does not flower readily, and seed production is unusual
except in its native habitat.
Economics
A good fodder plant, and much used in Sri Lanka as a soil binder
and organic-matter builder in upland tea estates (Bor, 1960; Andrew, 1971).
It is also used as a fodder grass in Fiji, Suriname, Malaysia and Puerto
Rico.
It is more persistent than elephant grass (Pennisetum purpureum) but
less productive and of lower nutritive value.
Animal production
It is used by dairy farmers in Fiji as green chop-chop for
zero grazing (Roberts, 1970a, b). On the podzolic soils of the Lelydrop
landscape in Suriname, planted cuttings of T. laxum after three years'
grazing at intervals of two months gave a live-weight increase of 300 kg/ha,
with a live-weight gain of 278 g per head per day over ten months (Appelman
& Dirven, 1972).
In Brazil, a mixed silage of 50 percent Tripsacum laxum, 30 percent
Lablab niger and 20 percent Saccharum officinarum decreased milk yield
by 10 percent, compared with maize silage; a T. laxum and S. officinarum
silage reduced yield by 19 percent (Assis et al., 1962).
Further reading
Appelman & Dirven, 1972.
Suitability for silage
Andrew (1971) states that it is capable of very high production.
It makes useful silage (Boudet, 1975; Medling, 1972; Assis et al., 1962).
It lost 12 percent of its dry matter during ensilage (Paterson, 1945).
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