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Graminae
Common names
Buffalo grass (Australia), St Augustine grass (Florida, United States).
Description
A hardy perennial, creeping extensively by means of branched rhizomes and many-noded
stolons. Exceedingly variable in size, the culms rising above the ground for 6-40 cm or
more, much branched from numerous nodes, the branches trailing, producing flowering stems
or fin-shaped tufts of leaves. Leaf- sheaths strongly compressed and keeled; leaves nearly
always glabrous except near the ligule, blades up to 12 mm wide, folded at first, then
expanded, usually rounded or obtuse; ligule a fringe of short hairs. Inflorescence a false
(or, rarely, a true) one- sided spike, 4-15 cm long, terminating the culm and each
flowering branch; central axis thick, swollen, flat on one surface, deeply hollowed out on
the other, each cavity containing a single spikelet or shoot spike of two to four
spikelets borne alternately on either side of a wavy middle ridge. Spikelets 4.5-5 mm
long, sessile, acute, awnless, glabrous, light green (Chippendall, 1955). St Augustine
grass is more robust and taller than buffalo grass, which is used for lawns. S. secundatum
var. variegatum is used as a decorative indoor plant.
Distribution
Native to North America, West Indies, Australia. Now widely distributed as a lawn
grass.
Season of growth
Spring, summer and autumn.
Altitude range
Sea-level to 800 m.
Rainfall requirements
Grows in humid areas, along the coast.
Drought tolerance
Tolerant of short dry periods.
Soil requirements
It will grow on a wide range of soils, and is particularly adapted to the muck soils of
the Florida Everglades coastal sands and alkaline soils. In Puerto Rico, cv. Roselawn does
best on soils rich in lime, and on steep sandy soils (Vicente-Chandler et al., 1953).
Ability to spread naturally
It spreads quickly by means of stolons. It does not produce seed.
Land preparation for establishment
Cuttings will establish in roughly prepared land, but good land preparation will
usually pay.
Sowing methods
Vegetative material is used for new plantings. Rooted runners are dug or disc-harrowed
into the soil, 30-40 cm apart in rows 60-80 cm apart, and preferably rolled afterwards. A
hectare of cuttings will plant about 10 ha of land.
Sowing time and rate
Early in the wet season.
Vigour of growth and growth rhythm
It is rather slow to cover the ground, but eventually provides a dense sward which
crowds out weeds.
Response to defoliation
The creeping flat stems of St Augustine grass root to form dense sods which stand
trampling and heavy grazing.
Grazing management
It should be grazed every second week down to 6 cm (Göhl, 1975), leaving sufficient
leaf area for the plant to produce the carbohydrates it needs for growth without depleting
its underground reserves (Vicente-Chandler et al., 1953). It takes time to recover if
grazed too closely. The herbage matures and becomes unpalatable very rapidly. An annual
application of 350-500 kg/ha of 0:8:24 fertilizer is usually applied.
Suitability for hay and silage
It can be made into useful silage (Bennett, 1973).
Toxicity
It contains about 1 percent of oxalates in the dry matter, but is not toxic
(García-Rivera & Morris, 1955).
Cultivars
'Roselawn' is used as a pasture forage (Bennett, 1973).
Diseases
It is subject to brownpatch in the United States.
Main attributes
Its ability to form a dense sod, its suitability for lawns. Its ability to grow on the
muck soils of Florida.
Main deficiencies
Its coarseness and general low productivity, its lack of seed production.
Frost tolerance
It survives frosts.
Response to light
It thrives in shaded areas and so is well adapted for lawns.
Pests
Some damage is done by the cinch bug (Blissus leucopterus) in the United States.
Palatability
Fairly palatable when young, but quickly loses palatability.
Chemical analysis and digestibility
Göhl (1975) records only one analysis of hay. The hay contained 6.7 percent crude
protein, 32.5 percent crude fibre, 3.7 percent ash, 2.7 percent ether extract and 54.4
percent nitrogen-free extract in the dry matter. The digestibility of the dry matter was
50.3 percent, of the crude protein 30.7 percent, and of the crude fibre 49.3 percent.
Natural habitat
In moist swampy soil near the sea-shore in the United States and southern Africa.
Tolerance to flooding
It will stand a good deal of flooding in Florida.
Fertilizer requirements
It should be well fertilized, especially with nitrogen. In Florida, two applications of
125 kg/ha a year are recommended.
Genetics and reproduction
2n=18, 20, 36, 54, 72 (Fedorov, 1974).
Animal production
Kidder (1952) recorded a live-weight gain of 2 250 kg/ha in one year on a St Augustine
grass pasture on organic soil in Florida. This result was never repeated. The experiment
was conducted in an area with extremely favourable moisture and temperature conditions,
while the animals were supplemented daily with 450 g of cotton-seed meal. In a ten-year
grazing experiment on St Augustine grass cv. Roselawn in Florida, the average daily gain
was 6.35 kg/ha from April to June, and 0.8 kg/ha during winter (Haines et al., 1965). The
pasture should carry seven yearlings per hectare all year, with surplus pasture made into
silage (Bennett, 1973).
Further reading
Haines et al., 1965.
Value for erosion control
Excellent.
Tolerance to salinity
It is a sea-shore grass and will withstand salt spray (Wheeler, 1950). |
