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Graminae
Synonyms
Echinochloa notabile (Hook. f.) Rhind.
Common names
Sabi grass (Australia), gonya grass (Zimbabwe), common urochloa
(southern Africa).
Description
A perennial, variable in size and habit (Burt et al., 1980)
sometimes stoloniferous or with a creeping rhizome. Culms 120 cm or more
high, sometimes rooting and branched from the lower nodes. Leaf-sheaths
with a ring of soft hairs at the nodes; leaf-blades 18 mm wide, hairy.
Inflorescence up to 15 cm long of four to 12 racemes, 2.5-9 cm long; spikelets
3-5 mm long, acuminate or shortly awned (Chippendall, 1955). It is distinguished
from U. panicoides in having a tubercle- based bristle in the middle of
the lower lemma in the fresh state (Whiteman & Gillard, 1971).
Distribution
Southern Africa, East Africa, Burma.
Season of growth
Summer.
Altitude range
700-1 000 m, but more adapted to the lower end of this range.
Rainfall requirements
It needs a rainy season of 10 to 16 weeks in summer with an
annual rainfall of 600-1 200 mm and a five- to nine-month dry season. It
responds well to early wet season storms.
Drought tolerance
It is drought enduring.
Soil requirements
It will grow in a wide range of soils, from clay loams to sands,
but appears to be more suitable for lighter soils with relatively high
fertility. It can tolerate both acid and alkaline soils.
Ability to spread naturally
It spreads well and becomes dominant in northern Australia
after fires.
Land preparation for establishment
A well-prepared seed-bed is preferable.
Sowing methods
In India it is sown by seed or rooted slips. Seed is surface
sown on to a fine seed-bed with 200 kg/ha superphosphate. Oversowing into
natural pastures where the soil fertility has been improved gave Urochloa
dominance after four years (Gillard, 1971).
Sowing depth and cover
It is surface- sown, and preferably rolled afterwards.
Sowing time and rate
Summer, at 1-6 kg/ha; or 2 kg/ha grass with 5-6 kg/ha Stylosanthes
humilis (north Queensland).
Number of seeds per kg.
60 600 (Queensland).
Seedling vigour
Good.
Vigour of growth and growth
rhythm
Flowering usually occurs continuously from three to four weeks
after the wet season begins, and the first seed is ripe in mid- December
(Queensland). It can make good growth ahead of its companion legume.
Response to defoliation
It stands quite heavy grazing.
Grazing management
At Katherine Research Station, northern Australia (lat. 14°35'S,
rainfall 950 mm), heavy wet season grazing at the rate of 3.3 steers per
hectare had no effect on the stand; continuous year-round grazing at 1.7
steers per hectare allowed the stand of Urochloa to increase slightly (Evans
& Winter, 1976).
Response to fire
It recovers well from fire in northern Australia (Falvey, 1979).
Dry-matter and green-matter
yields
In India, Singh and Chatterjee (1968) recorded a dry-matter
yield of 4 000 kg/ha when fertilized with 34 kg P and 44 kg N/ha (lat.
23°N, altitude 625 m, rainfall 1 320 mm). Good yields were also obtained
in Zimbabwe under a 500 mm rainfall. In northern Australia in association
with Stylosanthes humilis it yielded from 800 to 6 520 kg DM/ha (grass
component), the higher figure being obtained with a fertilizer application
of 25 kg P and 85 kg N/ha (lat. 19°S, altitude 50 m, rainfall 860 mm).
The legume only contributed 25 kg/ha. Where both components yielded well
(at 14°S, 200 m altitude, 800 mm rainfall) the grass yielded 4 117
kg DM/ha and the legume 3 438 kg/ha (Whiteman & Gillard, 1971). In
Thailand, in association with S. hamata cv. Verano and native grasses,
it produced a total of 11 245 kg/ha per year of which 8 208 kg/ha was stylo
and 1 561 kg/ha sabi grass (Humphreys, 1978). In Fiji it yielded 73 tonnes
DM/ha when fertilized with 450 kg/ha superphosphate; 23 percent of the
yield was made in the dry season (Partridge, 1979a).
Suitability for hay and
silage
It makes good hay.
Toxicity
No toxicity has been recorded by Everist (1974).
Seed yield
Up to four direct-headed crops per year have been obtained
in northern Australia. Seed yield is 100-130 kg/ha per year.
Cultivars
'Nixon'described above. Derived from CPI 6559 introduced
from Harare, Zimbabwe, and developed by B. Nixon at Katherine, northern
Australia.
Diseases
It is not subject to major diseases.
Main attributes
Its quick growth and free-seeding habit, providing a quick
early cover on overgrazed pastures, or when overseeding with cultivation.
Main deficiencies
It may be too palatable. It may not grow on heavy clays.
Optimum temperature for
growth
It can withstand high temperatures (Whyte, 1964).
Frost tolerance
It makes good winter growth, but is checked by frost. Light
frosts did not affect it at Yarrowmere near Pentland in inland north Queensland
(Burt, personal communication).
Latitudinal limits
Collected as far south as 25°S at 1 000 m elevation in
Africa (Whiteman & Gillard, 1971).
Ability to compete with
weeds
Good.
Maximum germination and
quality required for sale
60 percent purity and 3 percent germination.
Pests
It has no major pests.
Palatability
Very good, even when dry (Göhl, 1975). Voluntary intake
was 50 percent better than that of Heteropogon contortus under similar
conditions in Australia (Whiteman & Gillard, 1971).
Response to photoperiod
It is day neutral.
Natural habitat
In grassland, usually in sheltered places, or in disturbed
areas.
Tolerance to flooding
It does not tolerate flooding (Anderson, 1970a, b).
Fertilizer requirements
It may need a complete fertilizer for establishment, but it
responds well to phosphorus and nitrogen. Weier (1977) has shown that it
has high nitrogenase activity associated with its roots and can fix nitrogen.
Compatibility with other
grasses and legumes
It combines with Stylosanthes humilis, but must be carefully
managed. Both S. humilis and S. hamata cv. Verano were successfully re-established
in Urochloa mosambicensis dominant pasture on Blain sandy loam by disc-harrowing
and oversowing (Falvey, 1979).
Genetics and reproduction
The chromosome numbers are 28, 30, 42 (Fedorov, 1974). It is
an aposporous apomict (Pritchard, 1970).
Seed production and harvesting
It is free-seeding, and three to five harvests per season may
be obtained. It is harvested by direct heading.
Animal production
In the Tipperary region of northern Australia, under set stocking
at one beast to 0.3-0.6 ha, cv. Nixon plus S. humilis has given up to 450
kg live-weight gain/ha per year (Austin, 1970). The pasture was sown with
200 kg/ha superphosphate and grazed at stocking rates of one beast to 0.4,
0.8 and 1.6 ha. When production had stabilized in the third year of the
trial, respective live- weight gains were 360, 154 and 76 kg/ha in 344
days. The much better performance at the higher stocking rate was due to
the much higher proportions of S. humilis maintained in the pasture. At
the start of the experiment the pastures had a uniform 25 percent legume
content, but two years later the legume proportions were 75, 35 and 8 percent
for the 0.4, 0.8 and 1.6 ha per animal stocking rates respectively (Whiteman
& Gillard, 1971).
Further reading
Harty, 1972; Urochloa, Urochloa mosambicensis, 1974; Whiteman
& Gillard, 1971.
Dormancy
There is post-harvest dormancy, but after six to 12 months'
storage germination is satisfactory (Harty, 1972), the delay being due
to physical obstruction of the embryo by the enclosing lemma and palea.
It germinates at 20- 30°C, moistened with KNO3 solution.
Value for erosion control
It has been used successfully in India.
Tolerance to salinity
All species of Urochloa in India show high sodium content.
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