Digitaria smutsii Stent

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Graminae

Common names

Woolly finger grass.

Description

A robust, tufted, non-stoloniferous perennial with culms up to 150 cm high, usually branched; lowest leaf-sheaths densely hairy at the base, the leaves otherwise glabrous or with scattered tubercle-based hairs on the lower sheaths, blades up to 60 cm long, 6-12 mm or more wide, expanded; ligule 2-3.5 mm long; eight to ten, sometimes four to six racemes up to 15 cm long, arranged digitately or, more often, alone or in whorls on a central axis up to 7 cm long, the lower often divided and compound in the lower half; spikelets 3.5-4 mm long, fairly conspicuously hairy (Chippendall, 1955).

Distribution

It occurs in the Transvaal, Orange Free State, northern Cape Province and parts of the Kalahari thornveld in southern Africa. The species was described from plants growing at Doornkloof, Field Marshal J.C. Smuts's home at Irene in the Transvaal (Chippendall, 1955).

Season of growth

Summer.

Drought tolerance

It is very drought resistant, surviving a severe drought at Moree in north-west New South Wales (Darley, 1967).

Soil requirements

It does well on sandy soils.

Ability to spread naturally

It spreads rapidly from stolons.

Land preparation for establishment

A well-prepared seed-bed is preferred, but root-stocks can be established in a rough seed-bed.

Sowing methods

Propagated by division of root-stocks or by seed.

Vigour of growth and growth rhythm

D. smutsii CPI16778A has excellent spring growth characteristics (Hacker, 1976).

Response to defoliation

It will stand heavy defoliation.

Grazing management

It will stand heavy grazing and can be managed by short- term grazing at high stocking followed by top-dressing with nitrogen after grazing.

Dry-matter and green-matter yields

In Sri Lanka an annual yield of 21.46 t/ha DM was obtained from a fully fertilized pasture (Pathirana & Siriwardene, 1973).

Main attributes

Its ability to spread rapidly; its tolerance to heavy grazing and its response to fertilizers.

Main deficiencies

Its poor seed production.

Ability to compete with weeds

It can compete successfully with weeds.

Palatability

It is closely grazed at the Veterinary Research Farm at Entebbe Uganda (van Rensburg, 1969).

Chemical analysis and digestibility

In mid-country Sri Lanka, analyses of D. smutsii at four weeks showed 17.2 percent dry matter and 13.35 percent crude protein and at six weeks 17.64 percent dry matter with 11.44 percent crude protein, when fully fertilized with 140 kg N, 196 kg P2O5 and 252 kg K2O/ha (Pathirana & Siriwardene, 1973).

Fertilizer requirements

It requires a balanced fertilizer as determined by soil tests. It responds readily to nitrogen.

Genetics and reproduction

D. smutsii CPI16778A is almost completely sterile, but others, e.g. CPI38869, are fertile. Hybridization is in progress (Hacker, 1976). 2n=18, 36 (Fedorov, 1974).

Seed production and harvesting

It does not produce much seed at Moree north-west New South Wales (Darley, 1967).

Further reading

Pathirana & Siriwardene, 1973.

Value for erosion control

It has been recommended for revegetating abandoned cropland in southern Africa.