Axonopus fissifolius


Scientific name

Axonopus fissifolius (Raddi) Kuhlm.

Synonyms

Axonopus affinis Chase
Paspalum fissifolium Raddi

Family/tribe

Family: Poaceae (alt. Gramineae) subfamily: Panicoideae tribe: Paniceae.

Common names

caratao grass, carpet grass, common carpet grass, Louisiana grass (USA);  mat grass, narrow-leaved (narrowleaf) carpet grass, durrington grass (Australia);  teppichrasengras (German);  grama-missioneira (Brazil);  zacate amargo (Mexico).

Morphological description

Shallow-rooted (>90 % of roots in the 0-5 cm layer) perennial, initially forming shortly rhizomatous tufts that quickly develop vigorous stolons with relatively short, glabrous oval-section (± 2 x 1.5 mm) internodes;  forms a dense mat with foliage 15-30 cm tall, and flowering culms mostly 30-60 cm;  can be mowed to a turf.  Leaf sheath compressed, keeled, largely glabrousligule a fringed membrane 0.5 mm long;  blades 4-6 (-8) mm wide, and 5-15 (-28) cm long, flat or folded, glabrous except for sparse spreading hairs on the lower margins of young leaves, bluntly acute at the tip.  Inflorescence a panicle comprising 2 or 3 (rarely 4-7) slender, spikelike racemes, paired or sub-digitately arranged on a long slender peduncle;  racemes (2-) 3-7 (-10) cm long;  spikelets, 1.7-2.8 mm long, 1 mm broad, inserted alternately either side of a flattened rachis;  caryopsis tan to pale brown, compressed-ellipsoid to lenticular , 1.4-1.8 mm long.  2.5-3 million seeds per kg.
Differs from A. compressus in having more slender culms and stolons, narrower leaves and shorter, more obtuse spikelets.

Distribution

Native to:
North America:  South and central USA, Mexico.
Central America and Caribbean:  Belize, Costa Rica, El Salvador, Grenada, Guatemala, Honduras, Nicaragua, Panama.
South America :  Argentina, Bolivia, Brazil, Colombia, Ecuador, Guyana, Paraguay, Uruguay, Venezuela.
Occurs on low, flat areas in humid and sub-humid warm temperate to tropical woodland and savannah .

Naturalised in:
Africa, Asia, Australia and the Pacific Islands.

Uses/applications

Used as a permanent pasture, ground cover and turf in moist, low fertility soils.  It is generally too low growing to be useful in cut-and-carry systems or for fodder conservation .

Ecology

Soil requirements

Adapted to well to moderately drained sandy or sandy-loam soils, but also to light clays and peats, flourishing in soils too infertile for Paspalum dilatatum .  Best in acid soils with pH (4.3-) 5-6 (-7), becoming chlorotic above pH 7.  Low tolerance of salinity (<4 dS/m).

Moisture

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Mostly found in areas with an annual rainfall of (750-) 1,000-2,000 (-4,000) mm.  It is not very drought -tolerant, although more so than A. compressus , colonising hilly, as well as flat country.  While preferring moist soils, it does not withstand prolonged flooding or permanently swampy conditions.

Temperature

Occurs from sea level to >3,000 m asl, and from near the equator to about 35° latitude, representing a significant range in average annual temperatures from (13-) 17-27°C.  Top growth is greatest between 27 and 32°C, and with a day length of 15 hours.  Temperatures below 13°C inhibit flowering.  Although found in the tropics, it appears to be best adapted to the subtropics.  It is found further south than A. compressus in Australia.  Tops are burnt off by heavy frost, but plants recover with the onset of warmer, moist conditions.

Light

Moderately shade tolerant but less so than A. compressus .

Reproductive development

A. fissifolius flowers over a wide range of daylengths, flowering throughout the growing season in most environments, with a peak between 12 and 14 hours.

Defoliation

It thrives under heavy grazing, giving reduced yields under infrequent or high cutting.  Frequent grazing also helps to maintain it in a vegetative state.

Fire

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Although mostly growing in areas where fire is not a problem, it recovers quickly from fire.

Agronomy

Establishment

A. fissifolius can be established vegetatively from runners/sprigs, or from seed.  Seedlings develop fairly slowly, so seed is best broadcast onto, or shallowly sown into, a well-prepared seedbed to give the best chance of establishment.  Subsequent rolling helps maintain soil moisture and ensures close contact between soil and seed.  Choice of sowing rate depends on quality of seedbed and the rate of ground cover required.  With a good seedbed where rate of cover is not an issue, 2-3 kg/ha of seed is adequate, while with a less well prepared seedbed or where rapid cover is important, 6-12 kg/ha may be necessary.

Fertiliser

Low rates of nitrogen can help to extend the otherwise fairly short growing season, and to maintain the sward in a vegetative state.  It does not appear to be very responsive to phosphorus, growing well in low P soils.  A. fissifolius is less responsive to applied nitrogen than is Paspalum dilatatum with which it is often found growing.  Mixed swards of the two species become P. dilatatum dominant with continued applications of nitrogen.

Compatibility (with other species)

As soil nitrogen levels decline and under regular defoliation , A. fissifolius can successfully invade pastures based on more fertility demanding species such as Paspalum dilatatum , Cynodon dactylon , and Setaria sphacelata .  It is not very competitive, and can be grown with stoloniferous or rhizomatous legumes.

Companion species

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Pests and diseases

It is not subject to any major diseases or insect pests, although it is attacked by grass webworm (Herpetogramma licarsisalis, Lepidoptera, Pyralidae), usually during rainy weather, and is affected by Axonopus chlorotic streak, a leaf hopper transmitted virus in New Guinea.  Nematodes including Meloidogyne sp., Pratylenchus pratensis and Radopholus similis can cause serious injury in stands on well-drained soils.

Ability to spread

A. fissifolius produces abundant light seed that is readily spread by water movement and vehicles, and through the dung of grazing animals.  Under favourable conditions, it spreads rapidly by stolons.

Weed potential

It is usually insufficiently aggressive to be considered a serious weed in fertile soils.  However, it has become a weed in some areas by virtue of its ability to colonise low fertility soils.

Feeding value

Nutritive value

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Nutritive value is generally much poorer than that of Paspalum dilatatum .  When mature, it provides only poor-quality roughage.  Crude protein, neutral detergent fibre and acid detergent fibre levels in 6 and 20 week old material have been measured at (10.3, 67.4, and 41.2) and (6.3, 69.6 and 43.4)% respectively.

Palatability/acceptability

It is fairly palatable while leafy, but palatability declines with the onset of flowering.  Horses eat the masses of seed-heads avoided by cattle.

Toxicity

No record of toxicity.

Production potential

Dry matter

DM yields are mostly in the range of 1-5 t/ha/yr, even in fertilised grass .

Animal production

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Animal live-weight gains are low compared with other grasses, with live-weight losses occurring in winter.  Live-weight gains from unfertilised A. fissifolius are usually <100 kg/ha/yr, but fertilised and with a good legume component can approach 700 kg/ha/yr.

Genetics/breeding

2n = 20, 40, 60, 80.

Seed production

Commercial seed is mostly produced in the humid sub-tropics, mostly as "opportunity" crops.  While in most other grass seed crops, stands are "cleared off" to produce a synchronous crop, and nitrogen fertiliser applied to promote tillering, this is generally not followed for seed crops of this species.  Crops ripen unevenly and are mostly harvested non-destructively, providing about 50 kg/ha of seed per pass.  Fresh seed should be dried at no more than 35ºC, to avoid damage to the seed.

Herbicide effects

Susceptible to DSMA, bentazon, bromoxynil, 2,2-DPA and metsulfuron methyl.  Tolerant of diclofop methyl.

Strengths

  • Grows on poor soil.
  • Good ground cover.
  • Tolerates heavy grazing.

Limitations

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Other comments

  

 

Selected references

Barnard, C. (1969) Herbage Plant Species. Australian Herbage Plant Registration Authority; Canberra, CSIRO Australia, Division of Plant Industries.
Bogdan, A.V. (1977) Tropical Pasture and Fodder Plants. pp. 44-45. (Longman Inc., New York).
Campbell, L.R.V. (1999) Paspalum dilatatum and Axonopus affinis in Australia. In: Loch, D.S. and Ferguson, J.E. (eds) Forage Seed Production Volume 2: Tropical and Subtropical Species. (CAB International, Oxon., UK).
Cassidy, G.J. (1971) Response of a mat grass - paspalum sward to fertilizer application. Tropical Grasslands, 5, 11-22.
Evans, D.O., Joy, R.J. and Chia, C.L. (1988) Cover Crops for orchards in Hawaii. Hawaii Institute of Tropical Agriculture and Human Resources, University of Hawaii at Manoa, Honolulu, Hawaii, USA. p. 14.
Jones, R.M. and Bunch, G.A. (2003) Experiences with farm pastures at the former CSIRO Samford Research Station, south-east Queensland, and how these relate to results from 40 years of research. Tropical Grasslands, 37, 151-164.
Lima, L.M.S., Alquini, Y., Brito, C.J.F.A. de, Deschamps, F.C. (2001) Degradação ruminal dos tecidos vegetais e composição bromatolÓgica de cultivares de Axonopus scoparius (Flüegge) Kuhlm. E Axonopus fissifolius (Raddi) Kuhlm. Ciência Rural, 31, 509-515.

Internet links

Cultivars

Cultivars

Country/date released

Details

None released to date.      

Promising accessions

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Promising accessions

Country

Details

None reported.