Blanket grass (Axonopus compressus)

Datasheet

Description

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Blanket grass (Axonopus compressus) sward, Maui, Hawaii

Blanket grass (Axonopus compressus) leaves, Maui, Hawaii

Common names

Blanket grass, broadleaf carpet grass, lawn grass, Louisiana grass, tropical carpet grass, savannah grass, Kearsney grass [English]; grama ancha, grama bahiana, grama brasilera, grama brasileña, alfombra, grama trenza, zacate amargo, nudillo, barbacoa, cañamazo dulce [Spanish]; pasto-chato, grama-são-carlos, grama curitibana, grama-sempre-verde, grama-tapete, capim-bananal [Portuguese]; rumput pahit, papahitan, jukut pahit [Indonesian]; cow grass, rumput parit [Malay]

Species

Axonopus compressus (Sw.) P. Beauv. [Poaceae]

Synonyms

Axonopus compressus var. australis G. A. Black, Milium compressum Sw. (USDA, 2011), Paspalum compressum (Sw.) Nees, Paspalum platycaule Willd. ex Steud., Paspalum platycaulon Poir. (FAO, 2011; Cook et al., 2005), Anatrophus compressus (Ecocrop, 2011).

Related feed(s)

Description

Blanket grass (Axonopus compressus (Sw.) P. Beauv.) is a robust creeping perennial grass that forms dense mats. Foliage generally reaches up to 15 cm high and flowering culms up to 30-45 cm high. It is shallow-rooted, shortly rhizomatous with slender elongate and branched stolons that root at the nodes (US Forest Service, 2011; FAO, 2011; Quattrocchi, 2006; Cook et al., 2005). Leaf blades are shiny, flat, folded, lanceolate, 4-15 cm long and 2.5-15 mm broad. Flowering culms are erect and laterally compressed. They bear racemose panicles. There are generally 2-3 racemes, although up to 5 is possible. The 2 upper racemes are paired and borne on a slender peduncle; they are generally one-sided. The secondary racemes usually remain hidden in the sheath (US Forest Service, 2011; Cook et al., 2005; Manidool, 1992). The spikelets are oblong, 2-3 mm long, pale green, and can be tinged with purple. The seed (grain) is a 2 mm long caryopsis. Blanket grass is variable in size depending on environmental conditions and management. It is often confused with Axonopus affinis but is more robust and stoloniferous, and its spikelets are longer and hairier (FAO, 2011).

Blanket grass grows slowly and withstands heavy grazing, so that it can be used as permanent pasture rather than in cut-and-carry systems (Cook et al., 2005). It is also a useful ground cover (see Environmental impact below) and is used as a lawn grass in tropical and subtropical areas (FAO, 2011; Cook et al., 2005). It is much valued as pasture and ground cover in palm oil or rubber plantations as it is highly tolerant of shading (Manidool, 1992).

Distribution

Blanket grass is a native of America, from the Southern USA to Argentina, and has been naturalised in many tropical and subtropical areas including tropical West Africa, South Africa, South-East Asia, Australia and the Pacific Islands. It is mainly found in pastures, roadsides and disturbed or shaded areas in humid and sub-humid lowland tropics, between 27°N and 27°S, and from sea level up to an altitude of 3000 m (FAO, 2011; US Forest Service, 2011; Quattrocchi, 2006). Blanket grass likes an average annual temperature between 19 and 27°C and an annual rainfall between 800 mm to 5000 mm (Cook et al., 2005). It can grow on a wide range of soils, including poorly fertile soils, from sandy-loams to light clays, provided moisture is readily available and pH is not above 7. It has low tolerance of drought and cannot withstand prolonged flooding or permanently swampy conditions (FAO, 2011; Cook et al., 2005). It has some frost tolerance: the tops burn but the plant recovers when warmer and moister conditions occur (Cook et al., 2005). Blanket grass responds well to moderate fertilizer applications. Though not a legume, blanket grass is reported to have some ability to fix atmospheric nitrogen. Though it prefers full sunlight, blanket grass has a remarkable tolerance to shaded conditions; it is thus commonly grown under plantation crops in the tropics (Partridge, 2003; Manidool, 1992).

Forage management

Blanket grass is mainly found in permanent pastures where it is grazed by ruminants, either in free ranging systems (Central and South America) or in silvopastoral systems (Asia and Oceania) (Stür et al., 1990). It usually propagates vegetatively as it is a poor seed producer (US Forest Service, 2011; Cook et al., 2005). When it is possible to sow it, a fine weed-free seed bed must be prepared. The seeds are then broadcast or shallowly sown and then rolled (FAO, 2011). Blanket grass can be sown with other species including trees (rubber, oil palm or coconut trees), other grasses (Axonopus fissifolius, Chrysopogon aciculatus), or legumes (Arachis pintoi, Lotus uliginosus, Trifolium repens, T. semipilosum, Desmodium triflorum, Vigna parkeri) (FAO, 2011; Cook et al., 2005). When sown with Bermuda grass (Cynodon dactylon) it may gradually become invasive (FAO, 2011).

Blanket grass withstands heavy grazing. Defoliation prevents blanket grass from flowering with the subsequent loss of nutritive value (FAO, 2011; Cook et al., 2005). Blanket grass is not suitable for hay and silage or as a standover crop for deferred feeding because of its low productivity and poor quality. The stems are coarse and have a very low nutritive value once they have flowered (FAO, 2011; Stür et al., 1990).

Environmental impact

Erosion control

Blanket grass is useful for preventing soil erosion in rubber, oil palm and coconut plantations, and for stabilizing slopes or banks of dams (FAO, 2011; Cook et al., 2005; Manidool, 1992).

Weed potential

Blanket grass may become a weed under favourable conditions such as high rainfall and high temperatures (Ecocrop, 2011; US Forest Service, 2011). In infertile soils and shaded conditions, blanket grass can invade pastures of higher nutritive value containing grasses such as dallis grass (Paspalum dilatatum), Bermuda grass (Cynodon dactylon) or golden millet (Setaria sphacelata) swards (Cook et al., 2005).

Nutritional aspects

Nutritional attributes

The nutritional quality of blanket grass depends on the region and production system. In Central America, blanket grass has been considered as a native unproductive grass species of low quality and low palatability, probably because it invades easily degraded pastures (Ibrahim et al., 2000). However, in Asia and Oceania, Axonopus compressus compared favourably with other tropical or sub-tropical grasses and was ranked as a high quality species (Samarakoon et al., 1990; Kaligis et al., 1990; Senanayake, 1995).

Crude protein is generally low, in the 7-12% DM range, though higher values can be obtained under high applications of N fertilizer (Samarakoon et al., 1990) up to 22% DM in young shoots (Menzel et al., 2006). NDF and ADF contents vary from 50 to 77% DM and from 33 to 45% DM respectively. A high content of non structural carbohydrates has also been reported, which may explain the high in vitro digestibility observed in some cases (Samarakoon et al., 1990). Axonopus compressus is rich in Fe (150-500 mg/kg DM) compared to other similar grasses (Menzel et al., 2006; Warly et al., 2010).

Potential constraints

No toxicity has been reported (2012).

Ruminants

Axonopus compressus is one of the main species used in grazing systems under tree plantations in Asia and Oceania because of its ability to grow and tolerate heavy grazing while maintaining quality under shade (light transmission less than 50%) (Stür et al., 1990; Samarakoon et al., 1990). In spite of the importance of Axonopus compressus in pastures, its nutritive value and its potential for livestock has not been widely investigated.

Digestibility

Typical in vitro DM digestibility values are in the 54-65% range. However, much lower (32%; Holm, 1971a) and much higher in vivo DM digestibility values (75%; Kaligis et al., 1990) have been reported. In vitro DM digestibility of Axonopus compressus herbage grown under shade was slightly higher (1-2 units) than that for the herbage grown in full sunlight, an effect contrary to much of the published literature (Samarakoon et al., 1990). Potential in vitro gas production of Axonopus compressus was low when sampled during the dry season but similar to other grass species during the rainy season (Evitayani et al., 2004b).

Sheep and lambs

Under intensive continuous grazing in the subtropics, daily live-weight gain in lambs was lower by 34% on a native grassland dominated by Axonopus compressus than on a native grassland dominated by Paspalum notatum (0.045 kg/lamb/d vs. 0.060 kg/lamb/d). This may have been related to the lower pasture in vitro OM digestibility (56% for Axonopus compressus vs. 65% for Paspalum notatum) (Aviles-Nova et al., 2008).

Goats

In goats fed ad libitum indoors, in vivo DM digestibility and voluntary intake of aged Axonopus compressus swards (12 weeks of regrowth, 37% dead material) were higher than those observed in several young or aged swards of similar grass species. At the same age of regrowth, voluntary intake was 19% and 28% higher for Axonopus compressus than for Guinea grass (Megathyrsus maximus) and Dallis grass (Paspalum dilatatum) swards respectively (Kaligis et al., 1990)

Cattle

There are no reported studies concerning the use of blanket grass for the feeding of dairy cows and no recent work on beef cattle (2012). In Japan, Axonopus compressus was found to be one of the most palatable grasses in a comparison between 10 pasture species for grazing cattle (Nada, 1985). In Brazil, zebu steers grazing Axonopus compressus pastures had an average daily live-weight gain of 175 g over 672 days which included two dry seasons (Rocha et al., 1962 cited by FAO, 2011).

Rabbits

Blanket grass is used as green forage by traditional rabbit raisers in Central Java during both the wet and the dry season (Prawirodigdo, 1985).

Nutritional tables

Tables of chemical composition and nutritional value

Blanket grass (Axonopus compressus), aerial part, fresh

Avg: average or predicted value; SD: standard deviation; Min: minimum value; Max: maximum value; Nb: number of values (samples) used