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Graminae
Common names
Nile grass (South Africa).
Description
A perennial with extensively creeping, rather wiry rhizomes.
Culms mostly 40-110 cm high, simple, slender, geniculate and sometimes
prostrate in the lower part. Leaves bright green, glabrous or scantily
hairy. Inflorescence mostly 15-25 cm long, usually made up of two to five
spikelike racemes, solitary and widely spaced on a central slender axis.
The lower racemes are 6-9 cm long, the upper shorter. Spikelets arranged
singly on distinct pedicels, or in pairs, with one pair almost sessile.
Spikelets 5 mm long, awnless, glabrous. It has the C3 photosynthesis (Oliveira
et al., 1973).
Distribution
Widespread in north-eastern and southern tropical Africa.
Altitude range
1 000-2 000 m.
Rainfall requirements
It occurs on valley bottoms where moisture accumulates in regions
with a rainfall of 625-1 500 mm.
Drought tolerance
As it occupies valley bottoms and vlei soils there is usually
sufficient soil moisture to allow it to survive, but it has little drought
tolerance.
Soil requirements
It inhabits topographic bottom land with a wide soil range
from sandy to black clay soils.
Ability to spread naturally
Good. It spreads by its creeping rhizomes.
Sowing methods
It is established vegetatively.
Response to fire
It should be protected from hot veld fires (Chippendall &
Crook, 1976).
Dry-matter and green-matter
yields
On old wattle plantations near Ermelo, eastern Transvaal, of
seven grasses tried (Botha, 1953), Nile grass gave best performance yielding
an average for the first three years of 13 200 kg/ha per year of hay.
Suitability for hay and
silage
It makes most palatable and nutritious hay (Chippendall &
Crook, 1976) and is used for silage in South Africa (Semple, 1970).
Toxicity
In Taiwan some minor phytotoxicity has been shown by the roots
of A. macrum towards lettuce seedlings (Chou, 1977). Ferulic, syringic,
p-coumaric, vanillic, p-hydroxybenzoic and (O-hydroxyphenyl)-acetic acids
were identified as active factors. In Zambia scouring occurs when cattle
move from the fibrous forest grazing to the rich plains' grasses consisting
of Echinochloa pyramidalis, Acroceras macrum, Hemarthria altissima, Leersia
hexandra, Vossia cuspidata and Echinochloa scabra (stagnina) and it may
be three to four months before they regain condition (Verboom & Brunt,
1970).
Diseases
It is susceptible to rust and other leaf diseases.
Main attributes
Its ability to vegetate moist valley bottoms and stand seasonal
flooding, its palatability and good hay quality.
Main deficiencies
Its ability to become a weed.
Ability to compete with
weeds
Good. It can become a weed itself and is difficult to plough
out. Thus it should not be used as a short-term ley (Chippendall &
Crook, 1976).
Palatability
It is very palatable (Verboom & Brunt, 1970). In the wildlife
areas it is heavily grazed in summer.
Response to photoperiod
It is indifferent to day length for flowering (Evans, Wardlaw
& Williams, 1964).
Chemical analysis and
digestibility
Göhl (1975) gives the analysis in Table 15.1.
Natural habitat
Swamps and seasonally-flooded damp grassland.
Tolerance to flooding
It tolerates seasonal flooding.
Fertilizer requirements
It will respond to fertilizers.
Compatibility with other
grasses and legumes
Clatworthy (1970) successfully grew Trifolium semipilosum and
Lotononis bainesii with A. macrum with added nitrogen to 74.6 kg N/ha per
cut. In the third-year no-N plots, increased yield due to legumes was 92
percent for T. semipilosum and 73 percent for Lotononis bainesii (of the
yield of pure grass plus N at 112 kg N/ha).
Genetics and reproduction
2n=36 (Fedorov, 1974).
Seed production and harvesting
It does not produce viable seed. Strains which yield viable
seed and are rust resistant are being sought.
Economics
It has been widely cultivated as a planted pasture in vleis
and wet soils, always being established vegetatively and requiring fertility
and responding to fertilizer. Common on shallowly flooded levees and margins
of the flood plain on the Kapic River in Zambia (Sayer & Lavieren,
1975) and in northern Zimbabwe along the Chambeshi River.
Animal production
No figures have been cited.
Further reading
Vesey-Fitzgerald, 1963.
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