Axonopus fissifolius (Raddi) Kuhlm.
Basionym: Paspalum fissifolium Raddi; Axonopus affinis Chase
Family: Poaceae (alt. Gramineae) subfamily: Panicoideae tribe: Paspaleae subtribe: Paspalinae.
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 × 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 glabrous; ligule 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 at 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.
Asia: 类地毯草 lei di tan cao (China); rumput permaidani (Malaysia)
English: caratao grass, carpet grass, common carpet grass, Louisiana grass (USA); mat grass, narrow-leaved (narrowleaf) carpet grass, Durrington grass (Australia)
Europe: Teppichrasengras (German); assonopo (Italian)
Latin America: grama-missioneira (Brazil); gramalote (Spanish); zacate amargo (Mexico)
Northern America: Mexico (s.), USA (Alabama, Arkansas, Florida, Georgia, Louisiana, Mississippi, North Carolina, Oklahoma (s.e.), South Carolina, Texas
Central America: Belize, Costa Rica, El Salvador, Guatemala, Honduras, Nicaragua, Panama
South America: Argentina, Bolivia, Brazil, Colombia, Guyana, Paraguay, Uruguay, Venezuela
Widely naturalized and used as a turf and forage in the humid tropics and subtropics in Africa, Asia, Australia and the Pacific Islands
Occurs on low, flat areas in humid and sub-humid warm temperate to tropical woodland and savannah.
Mostly found in areas with an annual rainfall of 750 mm up to 4,000 mm. Drought tolerance is low but higher than in A. compressus. While preferring moist soils, it is not well adapted to prolonged flooding or swampy conditions.
Best growth on long days (15 h). Moderately shade-tolerant, but less so than A. compressus.
A. fissifolius flowers over a wide range of daylengths, seed production being greatest at 12‒14 h daylength.
Thrives under heavy grazing, down to stubble height of 5‒5.7 cm. Frequent grazing also helps to maintain it in a vegetative state.
Although mostly growing in areas where fire is not a problem, it recovers quickly from fire.
When seed is available, it is broadcast onto, or shallowly sown into, a well-prepared seedbed or ashes after a scrub burn. 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; 5‒15 kg/ha are recommended.
Adapted to low-fertility soils but will respond to fertilizers, particularly nitrogen, however, with low use efficiency.
Dominates annual weeds in forages. As soil nitrogen levels decline, because of its low-fertility requirements A. fissifolius can successfully invade pastures of more fertility demanding species such as Paspalum dilatatum and Cynodon dactylon.
Although a range of fungi and nematodes have been found on A. fissifolius, biotic constraints are not considered to be a production-limiting factor.
It can become a troublesome weed in the wet tropics.
Much lower than e.g. Paspalum dilatatum. Reported CP of fresh grass: 7.0%, dropping after seeding to 4‒6%; data from south Brazil: 10.3% CP after 6 weeks, 6.3% after 20 weeks. In vivo organic matter digestibility of fresh grass: 66.0%.
Fairly palatable in vegetative state. Usually well-grazed in association with companion legume.
No record of toxicity.
DM yields are low in comparison with other pasture grasses; mostly in the range of 1‒5 t/ha/yr, even in fertilised grass.
Live-weight gains recorded on unfertilised A. fissifolius are very low (70‒170 kg/ha).
2n = 20, 40, 60, 80.
Commercial seed is largely 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 fertilizer 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 35 ºC, to avoid damage to the seed.
Susceptible to DSMA, bentazon, bromoxynil, 2,2-DPA and metsulfuron methyl. Tolerant of diclofop methyl.
Bogdan, A.V. (1977) Tropical Pasture and Fodder Plants. Longman Inc., New York, USA. p. 44–45.
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. CABI Publishing, Wallingford, Oxon, UK. p. 325–333.
Evans, D.O., Joy, R.J. and Chia, C.L. (1988) Cover Crops for Orchards in Hawaii. University of Hawaii at Manoa, Honolulu, Hawaii, USA. hdl.handle.net/10125/5989
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. bit.ly/2ws2wt2
Lima, L.M.S., Alquini, Y., Brito, C.J.F.A. de and 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. doi.org/10.1590/S0103-84782001000300025