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Graminae
Description
Densely tufted perennial up to 90 cm high. Inflorescence usually
a single raceme-pair with green or purplish racemes, the upper with a 1416
mm glabrous raceme base; spikelets 14-16 mm long with awns 70-100 mm long
(Napper, 1965).
Distribution
Throughout tropical Africa, mainly in Central Africa.
Altitude range
1 000-3 000 m.
Rainfall requirements
It grows in a rainfall regime of 750-1 250 mm in Tanzania.
Soil requirements
It grows on poorly drained laterized soils on granite in the
southern highlands near Njombe, Tanzania. The soils are poor in minerals,
and mineralized licks are needed for cattle grazing the pastures. The pH
is 5.0-6.0.
Response to fire
Burning every two years in October or November after the first
rains maintained the Exotheca abyssinica/Hyparrhenia bracteata pasture
(Compère, 1968).
Minimum temperature for
growth
It grows where the minimum temperature is under 18°C.
Frost tolerance
Good.
Latitudinal limits
Mainly 0-18°S.
Palatability
It has tough leaves and is grazed only when young.
Chemical analysis and
digestibility
Dougall and Bogdan (1960) recorded 13.6 percent crude protein,
33.1 percent crude fibre, 5.8 percent ash, 2.4 percent ether extract and
45.1 percent nitrogen-free extract in the dry matter at the fresh, early
bloom stage in Kenya.
Natural habitat
Montane grassland.
Tolerance to flooding
It grows on seasonally wet ground.
Genetics and reproduction
2n=20 (Fedorov, 1974).
Economics
It is a high-altitude species which tolerates low soil fertility
and is not highly regarded as a pasture.
Animal production
Exotheca grasslands have a low carrying capacity, typically
one animal per five to ten hectares and the nutritive value of the herbage
is low throughout the year (Dougall, 1960). They are suitable for game
and forest reserves. Under uncontrolled grazing the fibrous species increase
and they are best improved by introduced species. In Rwanda and Burundi,
Compère (1968) recorded a live- weight gain of 70-90 kg/ha on an
Exotheca abyssinica/Eragrostis boehmii pasture.
Further reading
Vesey-Fitzgerald, 1963.
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