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Graminae
Common names
Nadi (pronounced "nandi") blue grass, nawai grass (Fiji), jiribilla
(Cuba), Antigua hay grass (West Indies).
Description
Tufted perennial with slender culms to 45 cm; nodes bearded,
leaves and sheaths glabrous; one raceme, sessile, first glume of the sessile
spikelet more or less indurate; first glume of the pedicelled spikelet
obovate, the upper margin purple, ciliate. In the strain Nadi blue grass,
the nodes are glabrous (Henty, 1969). It has blue-tinged leaves. When the
plants are young the stems are a bright mauve- blue colour (Parham, 1955).
It differs from D. annulatum in having the first glume of the sessile spikelet
winged, with no medial nerve and a short, ciliate ligule (Dabadghao &
Shankarnarayan, 1973).
Distribution
Native to India, Burma, Sri Lanka, Malaysia, China, New Guinea
and Fiji.
Season of growth
Summer.
Altitude range
600-1 000 m.
Rainfall requirements
It is an important grass in the "dry" zone of Fiji where rainfall
ranges from 1 500-2 500 mm a year with a dry season from May to November.
However, it does not produce well in dry weather.
Drought tolerance
It tolerates a rather dry winter-spring well, but makes little
growth in dry weather.
Soil requirements
It prefers dry, sandy habitats in Kerala, India.
Ability to spread naturally
It spreads well by vigorous stolons under moderate grazing.
Land preparation for establishment
In Fiji, burn the mission grass (Pennisetum polystachyon and,
without cultivation, broadcast seed on the surface. (Partridge, personal
communication).
Sowing methods
It is propagated by seed or by division of the roots. Broadcast
the seed by hand or from aircraft on to burnt mission grass.
Sowing time and rate
Sow at a minimum rate of 2 kg/ha at the beginning of the wet
season in November-December in Fiji (Partridge, personal communication).
Seed treatment before
planting
De-awning makes seed distribution more even (Partridge, personal
communication).
Seedling vigour
Very good.
Vigour of growth and growth
rhythm
It flowers in May and June at the beginning of the dry season
in Fiji, after which the quality and quantity of growth decline rapidly
(Partridge & Ranacou, 1974).
Response to defoliation
It forms a close turf when grazed.
Grazing management
It is very resistant to heavy grazing.
Response to fire
If rested to provide a body of grass it burns well, but if
burnt when grazed the results may be patchy.
Dry-matter and green-matter
yields
From 1950-52, the average green-matter yield of Nadi blue grass
at Sigatoka was 22 725 kg/ha (Roberts, 1970a, b). At Sigatoka, Fiji, Nadi
blue grass yielded an average of 11 500 kg DM/ha per year in 1971-72 with
31 percent of the yield in 1972 in the dry season (Partridge, 1979a).
Suitability for hay and
silage
It makes a high-quality hay.
Value as a standover or
deferred feed
It holds its palatability to maturity.
Toxicity
None reported.
Cultivars
In Maharashtra State, India, Oke (1971) recommends two new
cultivars, Marvel 40 and Marvel 93, which produce 40-100 percent more dry
matter than the naturally occurring strain.
Main attributes
Its ability to colonize and spread by both seed and runners
where fertilizers are not applied (Roberts, 1970a, b) in the "dry" zone
of Fiji with 2 000 mm of rain a year. Its low fertility requirement, tolerance
to waterlogging, tolerance of heavy grazing and good ground cover for the
control of erosion and weeds (Partridge, 1979b).
Main deficiencies
It grows poorly in dry weather and establishment of legume
in the sward without cultivation is difficult.
Optimum temperature for
growth
It makes most growth between 32-35°C in Fiji.
Minimum temperature for
growth
About 12-14°C in July in Fiji.
Response to light
It grows well under coconuts and Pinus caribea in Fiji.
Ability to compete with
weeds
It is a strong competitor with weeds on the unfertilized hill
soils of the dry zone of Fiji (Roberts, 1970a, b).
Palatability
Excellent, even to maturity (Parham, 1955).
Response to photoperiod
It is a short-day plant. Seed ripens in early June in Fiji.
Chemical analysis and
digestibility
Crude protein contents range from 6.3 percent of the dry matter
in the wet seasons to less than 2.5 percent in the dry season in Fiji (Partridge
& Ranacou, 1974).
Natural habitat
Swampy places, open humid woodland, black cotton soils.
Tolerance to flooding
It is quite tolerant of waterlogging (Partridge, 1979b) and
is suited to the waterlogged black clays.
Fertilizer requirements
It has a low fertility requirement.
Compatibility with other
grasses and legumes
It combines well with Stylosanthes hamata and siratro (Macroptilium
atropurpureum) and the naturalized legumes Desmodium heterophyllum, D.
triflorum, Alysicarpus vaginalis and Mimosa pudica in Fiji (Partridge,
1979b).
Genetics and reproduction
2n= 40, 60 (Fedorov, 1974).
Seed production and harvesting
Seed is produced in April and May in Fiji.
Economics
One of the best pasture grasses in the dry areas of Fiji and
the West Indies.
Animal production
On Nadi blue grass alone, the annual live-weight gain of steers
was 150 kg/ha in 1970/71, 105 kg/ha in 1971/72, and 95 kg/ha in 1972/73,
to give a mean annual live-weight gain of 110 kg/ha (Partridge & Ranacou,
1974). With 10 percent Leucaena leucocephala (vaivai) in the pasture the
mean live-weight gain was 170 kg/ha and, with 20 percent, 270 kg/ ha. With
siratro and superphosphate at one beast to 0.4 hectare, the annual live-weight
gain was 364 kg/ha. At higher stocking rates, siratro declined but naturalized
legumes increased and a live-weight gain of 380 kg/ha at a stocking rate
of 3.5 beasts per hectare was optimum (Partridge, 1979b).
Further reading
Parham, 1955; Partridge, 1979b.
Dormancy
Germination improves up to nine months in storage (Parham,
1960).
Value for erosion control
Excellent. It colonizes bare areas quickly by both seed and
runners (Roberts, 1970a, b).
Sowing depth
Good germination results from surface sowing.
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