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Graminae
Common names
Woolly-top or feather-top Rhodes grass (Australia), blackseed
(Kenya), feather finger grass (United States), feather-top chloris (South
Africa).
Description
A variable annual; culms 15-90 cm high, often decumbens and
rooting from the lower nodes; leaf-blades acute or acuminate; seven to
15 spikes, usually erect and forming an almost spike-like inflorescence;
spikelets 3-5 mm long, with one bisexual floret and one, more rarely two,
empty lemmas (Chippendall, 1955). The ripe spikelets are black and have
longer awns than Rhodes grass (Bogdan & Pratt, 1967).
Distribution
Widely distributed throughout the tropics, common on roadsides.
Season of growth
Summer.
Altitude range
Sea-level to 2 000 m.
Rainfall requirements
It does well in the 500-750 mm rainfall zone with a dominantly
summer incidence. The minimum rainfall is 375 mm.
Drought tolerance
Being an annual it is not regarded as drought tolerant.
Soil requirements
It prefers heavy soils and does well on black cracking clays
in Queensland, Australia, but has a wide soil range.
Ability to spread naturally
It produces abundant seed, which sheds and, being light, is
easily transported by wind and water. A little is spread by livestock movements.
In Queensland it soon occupies vacant spots in lucerne fields under 650-700
mm rain-fed conditions.
Land preparation for establishment
A rough seed-bed is all that is needed for oversowing.
Sowing methods
Broadcast the seed.
Sowing depth and cover
Sow on surface and roll if moisture is low.
Sowing time and rate
In summer at 0.5 kg/ha of pure seed.
Number of seeds per kg.
About 20 000 000 spikelets containing one caryopsis each (Bogdan
& Pratt, 1967).
Tolerance to herbicides
It has been removed from lucerne fields by an application of
Dalapon at about 6 kg/ha, sprayed at a height of 7.5 cm. Thorough land
preparation and cultivation of fallows helps to reduce its dominance.
Seedling vigour
Good.
Vigour of growth and growth
rhythm
It has a short growing season.
Response to defoliation
Being an annual, it has little persistence under grazing, but
was found as the final result of overgrazing a perennial sward at Matapos,
Zimbabwe (Rattray, 1960a).
Grazing management
When used as a reseeding grass in rangeland it should be allowed
to seed periodically to provide a thicker stand.
Response to fire
It is easily destroyed by fire. An intense fire could destroy
a lot of shed seed.
Suitability for hay and
silage
It makes somewhat inferior hay. Cut at flowering.
Value as a standover or
deferred feed
Being an annual it soon breaks down after maturity.
Seed yield
Similar to Rhodes grass (about 100-650 kg/ha).
Optimum temperature for
growth
About 25-30°C.
Frost tolerance
It is killed by frost.
Response to light
It will grow in shade, but prefers open country (Whyte, 1964).
Ability to compete with
weeds
Good in an annual situation, but it is regarded as a weed itself
in Queensland's agricultural areas.
Palatability
Its palatability is fair only.
Chemical analysis and
digestibility
It has 12-13 percent crude protein in the dry matter at fresh,
full bloom stage (Bogdan & Pratt, 1967). Hay in Zimbabwe contained
10.3 percent crude protein in the dry matter on a 10 percent dry-matter
basis (Göhl, 1975).
Natural habitat
Roadsides and grasslands as a weed, secondary in cultivation.
Tolerance to flooding
It will not withstand flooding.
Compatibility with other
grasses and legumes
Being an annual, it is not persistent but quick regeneration
from seed allows it to establish quickly in vacant situations in crops
and along roadsides.
Genetics and reproduction
2n=14, 20, 26, 30 (Fedorov, 1974).
Seed production and harvesting
It seeds heavily, and the seed can be harvested as for Rhodes
grass (Chloris gayana). The seed consists of a spikelet and one caryopsis.
Economics
It has been used with some success by L.H. Brown in reseeding
the Mwea Plains south of Embu (Kenya) (Bogdan & Pratt, 1967). In Queensland,
Australia, it is regarded as a weed in cultivated and waste places. It
can be troublesome in wool.
Further reading
Humphrey, 1960a.
Value for erosion control
It is one of the first grasses to colonize bare ground, and
has been used for reseeding denuded rangeland.
Tolerance to salinity
It is a common grass of the saline or user tracts of north-west
India (Bor, 1960) and forms 20 percent of the vegetation in the Mehesana
district of the Rann of Kutch, India, on alkaline land (Whyte, 1964).
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