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Graminae
Common names
Molasses grass (Australia), gordura (South America), calinguero
(Costa Rica), melado (Cuba), herbe à miel, Venezuela grass (India).
Description
Tufted perennial up to 150 cm high, often sticky, with a characteristic
odour of molasses or cumin. Pubescent leaf-blades. Panicle 10-30 cm long
with small glabrous spikelets 1.5 to nearly 2.5 mm long, awn 6-16 mm (Napper,
1965).
Distribution
Tropical and southern Africa and Brazil, introduced to many
tropical countries as a fodder grass and now naturalized.
Altitude range
800-2 000 m.
Rainfall requirements
It needs moderate to high rainfall in excess of 750 mm. The
normal range is 960 to 1 706 mm (Russell & Webb, 1976).
Drought tolerance
Relatively drought-hardy over a dry season of four to five
months.
Soil requirements
It is tolerant to soils of fairly low fertility, high aluminium
(Spain & Andrew, 1977) and light texture but will respond to more fertile
soils. It does well in ashes left from a scrub burn, and on steep hillsides
and road cuttings. It needs good drainage.
Ability to spread naturally
Molasses grass spreads quickly under favourable conditions.
Land preparation for establishment
It is usually established on burnt country to give a quick
cover to suppress weeds. A rough cultivation will usually suffice if a
burn is not obtainable.
Sowing methods
It is usually sown by seed, broadcast on a clean seed-bed and
mixed with sawdust or rice hulls for even distribution. It can be undersown
with cereal crops.
Sowing depth and cover
It is surface sown, with or without a light covering, and should
be sown no deeper than 2.5 cm (Bogdan, 1964).
Sowing time and rate
It is best to sow just before the expected normal rainy season
at 1.5 kg/ha or more.
Number of seeds per kg.
Spikelets ("seed") 6-15 million.
Seed treatment before
planting
The seed can be hammer-milled to improve germination and seed
handling.
Tolerance to herbicides
It can be killed by spraying with 2.2-DPA at 2.3 kg of a 740
g AI/kg product (e.g. Dowpon) plus paraquat at 85 ml of a 200 g AI/litre
product (e.g. Gramoxone) plus wetting agent at 250 ml per litre of water
(Tilley, 1977).
Seedling vigour
Excellent. It establishes quickly.
Vigour of growth and growth
rhythm
It is a vigorous grass and is valuable as a pioneer species
to suppress weeds and hold disturbed soil (ashes or a finely prepared cultivation)
against erosion.
Response to defoliation
It does not stand grazing below 15 cm because the crowns are
well above the ground.
Grazing management
It should be well established before grazing and then grazed
sparingly. Heavy stocking thins it out.
Response to fire
When mature it will burn so fiercely that its own seeds and
roots are killed, leaving the land clear for future plantings such as Guinea
grass and centro (Henty, 1969).
Dry-matter and green-matter
yields
In Colombia, dry-matter yields reach 6 0008 000 kg/ha per year.
This yield is doubled with 150 kg N/ha (Crowder, Chaverra & Lotero,
1970). In Fiji an average yield of 4 814 kg/ha of dry matter with a crude
protein content of 6.8 percent was obtained over a three-year period (Roberts,
1970a, b). In Nigeria, annual dry-matter yield at Agege was 6 500 kg/ha
(Adegbola, 1964).
Suitability for hay and
silage
Medling (1972) made satisfactory silage in plastic bags when
10 percent molasses was added.
Value as a standover or
deferred feed
In São Paulo, Brazil, molasses grass spelled during
a growing season could be cut in the winter without affecting root reserves
or subsequent spring growth (da Rocha et al., 1960).
Toxicity
No toxicity has been reported by Everist (1974).
Seed yield
It yields up to 280 kg/ha by hand harvesting. Jones (1973)
records 134 kg/ha.
Cultivars
No cultivars are registered in Australia. In Kenya there were
differences between the ordinary cultivated form and local wild Kenya ecotypes
which varied among themselves in many characters. Two of these ecotypes
have been named 'Mbooni' and 'Chania River'. They form more even stands
and are resistant to "small leaf" disease, but give lower seed yields (Bogdan,
1960). In Brazil four more- or-less distinct cultivated varieties are recognized:
'Roxo', 'Cabelo de Negro', 'Francana' and 'Branco'. 'Roxo' is the most
widely used (Barnard, 1969).
Diseases
A "small leaf" disease is present in Kenya.
Main attributes
Its quick establishment and ground cover which suppresses weeds,
and, when used as a pioneer plant, its inflammability at maturity, paving
a way for establishment of more productive pastures.
Main deficiencies
Its susceptibility to fire. It should not be sown as the sole
grass species in an area, as it is transient.
Optimum temperature for
growth
Ludlow and Wilson (1970b) found growth at 30°C was 1.36
times greater than at 20°C.
Minimum temperature for
growth
Mean temperature of the coldest month ranges from 6.1-14.5°C
(Russell & Webb, 1976).G
Frost tolerance
It is sensitive to frost, and repeated heavy frost will kill
it.
Latitudinal limits
15.9-30.5° N and S (Russell & Webb, 1976).
Response to light
Molasses grass tolerates partial shade.
Ability to compete with
weeds
Outstanding on newly burnt land in Laos (Thomas & Humphreys,
1970), and on roadsides in areas difficult to cultivate. In the Andes it
is grown up to 2 000 m to suppress weed growth (Roseveare, 1948).
Maximum germination and
quality required for sale
30 percent germinable seeds; 40 percent purity (Queensland).
Germinate at 20-30°C moistened with water. Germination is increased
by exposure to light.
Pests
There are no major pests.
Palatability
It is very palatable to stock.
Response to photoperiod
It is a short-day plant.
Chemical analysis and
digestibility
In Costa Rica analysis of material at floral initiation revealed
8.97 percent crude protein, 25.20 percent crude fibre, 44.89 percent nitrogen-free
extract, 3.61 percent ether extract and 7.33 percent ash in the dry matter
on a 10 percent moisture basis (Gonzalez & Pacheco, 1970). Göhl
(1975) lists analyses from Laos, Puerto Rico, India and Kenya.
Natural habitat
Grassland, shady places and rocky slopes in subhumid and humid
climates.
Tolerance to flooding
It does not tolerate flooding.
Fertilizer requirements
As a pioneer species sown on the ashes of scrub burns, initial
fertility may be high enough for establishment. The critical value of phosphorus
as a percentage of the dry matter at the immediate pre-flowering stage
is 0.18.
Compatibility with other
grasses and legumes
Molasses grass usually dominates other grasses initially but
it combines well with legumes, for example Centrosema pubescens in Brazil,
Neonotonia wightii (glycine), Macroptilium atropurpureum, Desmodium spp.,
etc. An aqueous mixture of molasses grass, siratro seed and fertilizer
is sprayed on newly established highway edges in Queensland, Australia,
to effect quick stabilization. It is a transient grass and should not be
the only species sown.
Genetics and reproduction
2n=36 (Fedorov, 1974). It is apomictic (Barnard, 1969).
Seed production and harvesting
It generally only produces seed in the lower latitudes.
Economics
It is an important pioneer grazing species to give cover on
newly cleared land. In Zaire the indigenous people claim it has insect-repellent
properties and use it as bedding for sitting fowls and bitches about to
give birth. In Manipur, India, it is believed mosquitoes avoid it, possibly
both the odour and viscid hairs being repellent (Bor, 1960).
Animal production
Using upgraded San Martinero cattle, daily gains of 0.48 percent
per head were obtained in Colombia with a stocking rate of one animal per
hectare (Crowder, Chaverra & Lotero, 1970).
Further reading
Bogdan, 1960; da Rocha et al., 1960.
Dormancy
There is no dormancy problem.
Value for erosion control
Excellent in high-rainfall areas and as a temporary cover in
subtropical areas of lower rainfall.
Tolerance to salinity
It does not tolerate salinity.
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