Tripsacum dactyloides (L.) L.

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Graminae

Common names

Eastern game grass (United States).

Description

Densely clumped grass with short, fibrous, woody rhizomes. Culms oval, stout, woody, solid, to 3-4 m tall, 3-5 cm thick at base, branching erect at centre of clump, geniculate peripherally, stilt-rooting from lower nodes, with a single ring of purple or mauve roots at the node, often growing through the persistent culm sheath; nodes glabrous, 5-14 cm long. Leaf-sheaths overlapping at base, clasping when young, lax and papery when old, often persistent, about 20 cm long; leaf-blades lanceolate-acuminate, to 1.5 m long and 10 cm wide, widest at about two-thirds of its length. Inflorescence to 30 cm long, terminal and axillary, of one to six racemes of unisexual spikelets, female basally for one-third to one- eighth of the length of the raceme, male distally (Gilliland et al., 1971). It differs from T. laxum in that the inflorescence is stiff, and the male spikelets are longer (7-8 mm).

Distribution

Western Hemisphere, United States to Brazil; Malaysia.

Season of growth

Summer.

Rainfall requirements

About 1 000-1 500 mm annually.

Soil requirements

It grows best on moist, well-drained, fertile soils.

Number of seeds per kg.

15 000 (United States).

Vigour of growth and growth rhythm

It makes major growth in early spring and stays green until frosts. It seeds from July to September in the United States.

Response to defoliation

This grass should not be cut closer than 25 cm from the ground.

Grazing management

It can be grazed during spring and summer, but deteriorates after frost and provides little winter grazing. Grazing is best if deferred at least 90 days every two to three years, to enable plants to produce seed.
Cattle have difficulty in biting through the tough midribs of the leaves, and the shallow-rooted stools are easily uprooted. It makes very little growth in dry weather. It is persistent, and stands can be maintained almost indefinitely under sound management (Whyte, Moir & Cooper, 1959). Inter- row shallow cultivation helps control weeds but deep cultivation destroys the shallow roots. It is seldom grazed, but generally cut for soilage or silage at six- to ten-week intervals at a height of 25 cm; it is fertilized with nitrogen as necessary. Generally less productive than elephant grass (Pennisetum purpureum) and lower in nutritive value.
Despite the above remarks, workers in Suriname found that, after the pasture was grazed for three years with rest periods of two months, a year without grazing put the pasture into excellent condition (Appelman & Dirven, 1972).

Dry-matter and green-matter yields

In Suriname it yielded 25 000 kg/ha of green matter in the first year without fertilizer, and 10 000 kg/ha in the second year (Appelman & Dirven, 1972).

Suitability for hay and silage

It is a choice hay plant and is usually managed for hay production in the United States, although no more than 50-60 percent of the current season's growth should be removed at any time during the growing season. For quality hay, it is cut at 15-20 cm when the seed-heads start appearing (Leithead, Yarlett & Shiflet, 1971).

Frost tolerance

It is susceptible to frost.

Response to photoperiod

Flowering is accelerated by short days (Evans, Wardlaw & Williams, 1964).

Tolerance to flooding

It does not tolerate standing water for long periods.

Compatibility with other grasses and legumes

It is usually grown as a pure stand, and inclusion of legumes is difficult.

Genetics and reproduction

2n=54, 70, 72 (Fedorov, 1974). It is a diplosporous apomict.

Economics

The grass is being quite extensively planted on rubber estates in Malaysia as a soil conditioner in drained swamps, and for mulching. It provides good fodder (Gilliland et al., 1971).

Further reading

Leithead, Yarlett & Shiflet, 1971.