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Graminae
Common names
Habana oat grass, grader grass (Australia).
Description
An annual, growing to 1.4 m; it turns a distinctive orange-red
colour as the seed-heads mature. The involucral spikelets are 6-7 mm long,
obliquely lanceolate with stout, coarsely tuberculate hairs on the keels
but glabrous elsewhere; fertile spikelet has a somewhat obtuse or acute
(but not pungent) callus scarcely 1 mm long; spatheoles very acute (Blake,
1969).
Distribution
Widespread in India, introduced to Australia.
Season of growth
Summer.
Rainfall requirements
500-1 250 mm in India; common in 1 000-1 500 mm in north Queensland.
Drought tolerance
It can withstand quite dry conditions in India.
Soil requirements
It is adapted to soils of moderate moisture content and declines
on soils with a moisture content in excess of 19.3 percent. It requires
moderate exchangeable calcium. Favours a sandy loam soil with a pH from
7.0-8.5, but grows on clay loams and well-drained lateritic soils.
Ability to spread naturally
It spreads rapidly by seed.
Number of seeds per kg.
633 000.
Tolerance to herbicides
It can be controlled by paraquat at 1.4 litres/ha of a 200g
AI/1 product (e.g. Gramoxone) plus surfactant at 250 ml per 200 litres
of water, when the plant is at the young seedling stage of growth; plants
must be thoroughly wetted. On well-grown grass, paraquat at 2.81/ha as
above can be used, but increasing the rate to 400 litres of water per hectare;
alternatively, 2,2-DPA at 2.3 kg of a 740g AI/kg product (e.g. Shirpon,
Ellapon, Dowpon) plus TCA at 9 kg of a 940g AI/kg product (e.g. TCA grass-killer)
per 200 1 of water can also be used. A wetting agent at 250 ml per 200
litres of water must be added and the plants thoroughly wetted. For pre-emergence
control of grass seedlings, trifluralin at 2.8 litres/ha of a 400g AI/1
product (e.g. Treflan EC) can be used, but it must be well incorporated
into the soil immediately following application. It will not control broad-leaved
weeds (Tilley, 1977).
Vigour of growth and growth
rhythm
It grows vigorously and flowers from October to January in
Madhya Pradesh, India.
Response to defoliation
Cutting at full flowering gives some control.
Grazing management
It is not grazed very much. Allowing the grass to remain undisturbed
suppresses seed germination by shading, and the shed seed soon deteriorates
(Sillar, 1969).
Response to fire
Burning encourages germination.
Main deficiencies
It has become an aggressive weed in sugar-cane fields in northern
Queensland.
Latitudinal limits
17-27°S; in tropical India, to 28°N (Sillar, 1969).
Ability to compete with
weeds
It can compete successfully with broad-leaved weeds.
Genetics and reproduction
2n=40 (Fedorov, 1974).
Economics
It becomes a pest in Queensland's sugar-cane fields in poorly-grown
sections of cane where cultivation has been neglected, but it will not
grow in shade, such as under a good cane crop. It can be troublesome on
headlands and roadways where it establishes very quickly. In Madhya Pradesh,
India, it has some fodder value and is used for thatching.
Animal production
No animal production figures have been cited.
Further reading
Tilley, 1977.
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