|
Graminae
Common names
Naivasha star grass (eastern Africa), estrella (South America),
Bermuda mejorado, Hawaiiano (Costa Rica).
Description
A large, robust, non-rhizomatous grass. True C. plectostachyus
is a diploid which can easily be identified by the small glumes, rarely
as long as one- third of the spikelet; soft foliage; racemes in two or
more whorls and arching stolon internodes (Harlan, de Wet & Rawal,
1970).
Distribution
C. plectostachyus has a fairly restricted natural distribution
along the Rift Valley through Ethiopia, Kenya, northern Uganda and northern
Tanzania.
Season of growth
Summer.
Altitude range
Sea-level to 2 000 m.
Rainfall requirements
It is adapted to semi-arid areas with rainfalls from 500-875
mm.
Drought tolerance
Very good.
Soil requirements
It has a wide range of tolerance from sandy loams to alluvial
silts and clays, and black cracking clay soils, but prefers soil of high
fertility.
Ability to spread naturally
Excellentunder good conditions its stoloniferous habit
allows it to spread rapidly.
Land preparation for establishment
Full land preparation is required for establishment from seed.
Sowing methods
It can be established from seed or by splits dug into the soil,
this latter requiring less land preparation.
Sowing depth and cover
Seed should be surface sown and lightly covered and rolled.
Sowing time and rate
In the wet season at 6.5 kg/ha.
Number of seeds per kg.
25-40 million florets with one caryopsis (Bogdan & Pratt,
1967).
Seed treatment before
planting
Treat with an insecticide.
Seedling vigour
Good.
Response to defoliation
Excellent. It can stand heavy grazing.
Grazing management
It should be grazed fairly heavily and top-dressed with nitrogen
as required.
Response to fire
It survives fire very well and quickly responds to subsequent
rain.
Dry-matter and green-matter
yields
Strickland (1976-77) recorded a range of dry-matter yields
of 1 300 kg/ha per month in summer to 300-1 100 kg/ha per month in winter
from three accessions tested at Samford, Queensland. In Nigeria, Moore
(1965) cut 3 300 kg/ha of C. plectostachyus/centro hay from cutting at
5-10 cm at eight-week intervals. At Gualaca, Panama it produced 6 000 kg
DM/ha without fertilizer and 32 000 kg DM/ha with 600 kg N/ha in a rainfall
regime of 3 997 mm a year (Rattray, 1973).
Suitability for hay and
silage
It makes quite good hay, and with the addition of 10 percent
molasses makes good silage (Medling, 1972).
Value as a standover or
deferred feed
It makes quite good deferred grazing.
Toxicity
No toxicity can be attributed to this grass in Queensland (Everist,
1974).
Seed yield
25 kg/ha from one harvest at Samford, Queensland (Strickland,
1976- 77).
Main attributes
Its rapid colonization of bare land and invasion of overgrazed
land.
Main deficiencies
It may become a little aggressive in cultivations.
Frost tolerance
It survives frost.
Response to light
It prefers to grow in full sunlight.
Ability to compete with
weeds
Excellent.
Palatability
It is extremely palatable.
Chemical analysis and
digestibility
In Costa Rica analysis of material at floral initiation revealed
14.98 percent crude protein, 26.20 percent crude fibre, 37.22 percent nitrogen-free
extract, 1.93 percent ether extract, and 9.67 percent ash in the dry matter
on a 10 percent moisture basis (Gonzalez & Pacheco, 1970). At Gualaca,
Panama, it contained 20-25 percent dry matter in the wet season and 47
percent dry matter in the dry season (Rattray, 1973).
Natural habitat
Dry lake beds.
Tolerance to flooding
Tolerates temporary flooding.
Fertilizer requirements
The optimum phosphorus content of the dry matter for growth
was determined by Falade (1975) as 0.305. It responds well to nitrogen.
Compatibility with other
grasses and legumes
It tends to form a monospecific sward, but will grow with Medicago
species, Trifolium semipilosum and Lotononis bainesii (Clatworthy, 1970).
Genetics and reproduction
A diploid2n=18 (Fedorov, 1974). Crossbreeding studies
have shown it to be completely isolated genetically (Harlan, de Wet &
Rawal, 1970).€
Animal production
Because of taxonomic confusion, until recently the literature
references to the role of C. plectostachyus may actually refer to other
species. It is, however, an excellent grazing grass and one which stabilizes
soil against wind and water erosion. In Zimbabwe, C. plectostachyus (?)
pastures fertilized with 270 kg nitrogen and 38 kg phosphorus per hectare
gave a liveweight gain of 830 kg/ha from the grazing of 12.4 heifers per
hectare (Rodel, 1970).
Further reading
Harlan, de Wet & Rawal, 1970.
Value for erosion control
Excellent. It has been used on the black cracking clay soils
on sloping cultivated land on the Darling Downs, Queensland, with success.
Tolerance to salinity
It is tolerant to alkaline soils and is always found in what
appear to be alkaline areas in Kenya.
|
