Stenotaphrum secundatum (Walt.) Kuntze

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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).