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Sustainable Agriculture in Hawaii
Cover Crops: Non-Legumes
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Broadleaf Carpet Grass

Axonopus compressus


Click here for a downloadable, printable pdf on Carpet Grass.
Summary
photo of Broadleaf Carpet Grass 01
Photo: USDA NRCS
  • Tropical and subtropical short perennial stoloniferous mat-like grass
  • In Hawai`i used for soil cover under orchard crops such as macadamia and coffee
  • Used for grazing in plantation crops (particularly coconut) but considered low quality forage
  • Used for soil cover under dense shade in established oil palm and rubber
  • Used as a cultivated lawn grass in Australia and USA
  • Used for erosion control applications
  • Excellent for weed suppression. Can become a troublesome weed itself.
  • Seed largely unavailable and must be sprigged
  • Alternate host of Rhizoctonia solani
  • Shade tolerant but grows in full sunlight also

Common Name
Its common name is broadleaf carpet grass or kulape (Tagalog) (Manidool).
 
Scientific Name
The scientific name is Axonopus compressus (Swartz) P. Beauv. (Manidool).
 
Cultivars
No information is available in this database on this topic.
 
Seed Description
Seeds are yellow-brown, elliptical, 1.25 mm long (Manidool).
 
Seedling Description
No information is available in this database on this topic.
 
Mature Plant Description
Broadleaf carpet grass is a short perennial, stoloniferous, dense mat-like spreading grass. Its leaves are 4-15 cm (11/2 - 6 in.) long, and 4-10 mm (1/6-3/8 in.) wide, broadly linear or lanceolate. It seldom reaches a height greater than 15 cm (6 in.) (FAO). There are usually two to four slender, dense spikes, 3-10 cm (1-4 in.) long. Spikelets are 2.2-2.8 mm long. The stems are slender, compressed, one to three noded (Bogdan). It is similar to A. affinis in most of its botanical characters but is more robust and stoloniferous (FAO).
NOTE: A. compresses (broadleaf carpet grass) and A. affinis (narrowleaf carpet grass) cannot be easily distinguished from one another by their general appearance because the leaf width can vary and hybridization occurs (Bogdan).
 
Temperature
Found in the tropics and subtropics (FAO).
 
Origin and Geographic Distribution
Broadleaf carpet grass occurs naturally in Mexico, Central America, tropical South America and the West Indies. It has been introduced into the southern eastern USA, Africa, southeastern Asia, the Philippines, Australia and the Pacific Islands. It has "naturalized" in many of these countries (Bogdan).
 
Ecology
Its natural habitat is subhumid to humid woodland and savannah, flourishing in moist soils (FAO).
 
Water
Broadleaf carpet grass requires a minimum rainfall of 775 mm (about 30 in.) (FAO). It cannot withstand waterlogging or flooding (Bogdan).
 
Nutrients
Broadleaf carpet grass often outcompetes other grasses on infertile soils (Bogdan). It does respond to fertilizer applications (Manidool).
 
Soil pH
Broadleaf carpet grass tolerates soil pH range 4.0 – 7.0 (NRCS).
 
Soil Type
Broadleaf carpet grass grows on a range of soil types, particularly sandy soils (Manidool) and fertile sandy loams (Bogdan). It is commonly found on sandy soils where it outcompetes other grasses as fertility declines (Bogdan).
 
Shade Tolerance
Broadleaf carpet grass is moderately to very shade tolerant but also grows well in full sunlight (Manidool).
 
Salinity Tolerance
No information is available in this database on this topic.
 
Herbicide Sensitivity
Manidool reports that broadleaf carpet grass is controlled as a weed by spraying with 1.1 kg MSMA + 0.6 kg sodium chlorate in 273 liters water.
 
Life Cycle
Young plants start growth in a circular patch. With little competition, the patch may reach a size of up to 1 meter in diameter in one season. It crowds out weeds and grasses and forms a dense mat-like cover. It flowers all year round, although little seed is produced in some environments (Manidool).
 
Seeding Rate
6 kg/ha (Manidool, FAO). Not usually seeded.
In Hawaii, broadleaf carpet grass is usually sprigged due to lack of seed sources.
 
Seeding Depth
Sow on the surface and roll after planting (FAO).
 
Seeding Method
Sow on the surface and roll after planting. It can be surface sown through a drill (FAO).
 
Seeding Dates
Year round in Hawai`i.
 
Inoculation
Not applicable. It is reported to be able to fix atmospheric N through associated microorganisms (Manidool).
 
Seed Cost
No information is available in this database on this topic.
 
Seed Availability
Not readily available.
 
Days to Flowering
No information is available in this database on this topic.
 
Days to Maturity
No information is available in this database on this topic.
 
Seed Production
No information is available in this database on this topic.
 
Seed Storage
No information is available in this database on this topic.
 
Growth Habit
Broadleaf carpet grass is a short spreading grass which generally reaches a height of about 15 cm, forming a dense mat over the ground surface (FAO).
 
Maximum Height
Broadleaf carpet grass grows to a maximum height of about 20-50 cm (8-20 in.) (Manidool).
 
Root System
No information is available in this database on this topic.
 
Establishment
Broadleaf carpet grass is usually vegetatively propagated by planting stolons (Manidool). Planting sprigs 2 ft by 2 ft or closer is recommended by Evans in Hawai`i. NRCS recommends a planting rate or 40-80 bu/ac (sprigs or stolons, maximum 3x3 ft. spacing).
 
Maintenance
No information is available in this database on this topic.
 
Mowing
When used as a lawn grass, it should be mown frequently (Manidool).
 
Incorporation
Not applicable. Not generally used as a green manure.
 
Harvesting
Not applicable. Not generally harvested.
 
Equipment
No information is available in this database on this topic.
 
Uses
  • Soil cover under macadamia and coffee in Hawai`i
  • Grazing in plantation crops (particularly coconut) but a low quality forage
  • Soil cover under dense shade in established oil palm and rubber
  • Cultivated lawn grass in Australia and USA
  • Erosion control applications
  • Weed suppression. Can become a troublesome weed itself.

Mixtures
Broadleaf carpet grass will grow in association with white clover (Trifolium repens) and Desmodium triflorum. It will gradually invade Cynodon dactylon in lawns (FAO). In Hawai`i it is reported to combine well with trefoil, Desmodium spp. and white clover (Evans).
 
Biomass
No information is available in this database on this topic.
 
N Contribution
Nitrogen concentrations of A. compressus range between 1-2% (Manidool). CSIRO workers have shown that it has an active nitrogenase system fixing 13 kg N/ha/day over a 12 week summer growing period (FAO).
 
Non-N Nutrient Contribution
No information is available in this database on this topic.
 
Effects on Water
No information is available in this database on this topic.
 
Effects on Soil
No information is available in this database on this topic.
 
Effects on Livestock
Broadleaf carpet grass is used for grazing in plantation crops (particularly coconuts) (Manidool). The quality of herbage is considered to be comparatively low and declines with plant age (Bogdan). Frequent grazing is preferred to maintain palatability and quality. It is usually grazed by tethered or freely grazing animals and rarely used in a cut-and-carry system. With mixed fertilizer applications rates of 300 kg/ha, it has yielded up to 5 t/ha of DM. In Brazil, Zebu steers grazing over 672 days achieved an average daily gain of 0.18-kg (Manidool).
 
Pest Effects, Insects
No information is available in this database on this topic.
 
Pest Effects, Nematodes
Burrowing, reniform, and root knot susceptible (personal communication, Robert Joy).
 
Pest Effects, Diseases
Alternate host of Rhizoctonia solani (Manidool).
 
Pest Effects, Weeds
Excellent for weed suppression but can become a troublesome weed itself. It often invades run-down old sown unfertilized pastures (Bogdan).
 
Pest Effects, Vertebrates
No information is available in this database on this topic.
 
Uses in the Pacific Region

  • Broadleaf carpet grass invasion of old Brachiaria mutica pastures have been reported in Fiji (Bogdan).
  • In Fiji it is considered a useful feed, especially if Mimosa pudica (sensitive plant) is grown with it (FAO).

Uses in Hawai`i
The Hawai`i Natural Resources Conservation Service Technical Guide broadleaf carpet grass. Their specification describes broadleaf carpet grass as follows:

  • Tolerates acid/low fertility soils;
  • pH range from 4.0-7.0;
  • Planting rate 40-80 bu/ac (sprigs or stolons, maximum 3x3 ft. spacing);
  • Low maintenance required;
  • Good shade tolerance;
  • Fair drought tolerance;
  • Rainfall range of 50+ inches;
  • Medium rate of establishment;
  • Elevation range from 0-3000 ft.
The Natural Resources Conservation Service Plant Materials Center has been working with an accession (9037941) for advanced testing for use as a ground cover in shady conditions, primarily orchard ground cover and more specifically for macadamia nut orchards. It will grow in full sun and should have applications for waterways, critical area plantings and other erosion prone areas. It makes a very acceptable turf. (R. Joy)
 
Several farmers in the Kona region report using broadleaf carpet grass with white clover under coffee. There are concerns (but no reports) about the carpet grass and coffee both being susceptible to root knot nematode.
 
Evans reports carpet grass being used successfully in Kona by coffee growers, with the more wear-resistant tropic lalo (Paspalum hieronymii) being used for access roads and equipment-bearing areas.
 
Dr. Joe DeFrank, UH Manoa, has a cover crop demonstration site using broadleaf carpet grass as a living mulch in papaya trials.

REFERENCES
Bogdan, A.V. 1977. Tropical Pasture and Fodder Plants. Longman Inc., New York. Pp.45-47.

Evans, Dale O., Joy, Robert J., & 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, United Stated. 16 pp.

FAO Web Site:
http://www.fao.org/WAICENT/FAOINFO/AGRICULT/AGP/AGPC/doc/pasture/Mainmenu.htm

Manidool, C. 1992. Axonopus compressus (Swartz) P. Beauv. In: ’t Mannetje, L. & Jones, R.M. (Editors): Plant Resources of South-East Asia No 4. Forages. Pudoc-DLO, Wageningen, the Netherlands. pp. 53-54.

USDA Natural Resources Conservation Service, Hawai`i Field Office Technical Guide, Section IV, Code 340 "Cover and Green Manure Crop" May 1992.

If you have used this plant as a cover crop in the Pacific Region, please email us with COMMENTS and FEEDBACK about this plant description so we can further refine this educational resource.

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Last updated on 9/23/02
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