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Congo grass (Brachiaria ruziziensis)

IMPORTANT INFORMATION: This datasheet is pending revision and updating; its contents are currently derived from FAO's Animal Feed Resources Information System (1991-2002) and from Bo Göhl's Tropical Feeds (1976-1982).

Datasheet

Description
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Common names 

Congo grass, Congo signal, Congo signal grass, Chinese cabbage, Kennedy ruzi, Kennedy ruzigrass, prostrate signal grass, ruzi, ruzigrass, ruzi grass [English]; Congo, Congo señal, gambutera, Kenia, pasto Congo, pasto ruzi, ruzi [Spanish]; ruzisiensis, capim congo [Portuguese]; herbe à bengali, ruzi [French]; rumput ruzi [Indonesian]; ya ruzi [Thai] (Miles et al., 1996; Schultze-Kraft et al., 1992)

Synonyms 

Urochloa ruziziensis (R. Germ. & C.M. Evrard) Crins; Urochloa ruziziensis (R. Germ. & Evrard) Morrone & Zuloaga; Brachiaria decumbens var. ruziziensis (R. Germ. & Evrard) Ndab.; (USDA, 2015; Quattrocchi, 2006)

Description 

Congo grass is a short-lived perennial (Husson et al., 2008). It is a tufted creeping (semi-prostrate) rhizomatous grass that can roots from the nodes and forms a dense leafy cover (Cook et al., 2005; Urio et al., 1988). Congo grass has a dense system of bunched, quickly growing roots that can go as deep as 1.8 m in the soil layer (Husson et al., 2008).

Congo grass culms grow from the nodes of the rhizomes and may reach 1.5 m high when flowering (Cook et al., 2005). The leaves are soft but hairy on both sides, lanceolate in shape and up to 25 cm long x 1-1.5 cm broad, light-green in colour

Inflorescence consists of 3–9 relatively long racemes (4–10 cm), bearing spikelets in 1 or 2 rows on one side of a broad, flattened and winged rachis (Cook et al., 2005). The spikelets are hairy, 5 mm long. Weight of 1000 grains is about 4 g (Husson et al., 2008).

Congo grass is very similar to Signal grass (Brachiaria decumbens) and has often been mistaken with it (Cook et al., 2005). It is however markedly less productive than signal grass which reduces its potential as a forage crop, particularly in low-fertile soils (Schultze-Kraft et al., 1992). Congo grass genetic material has been used to hybridize with Brachiaria brizantha and yielded a series of cultivars known as Mulato (Argel et al., 2007; Argel et al., 2005).

Congo grass is valuable forage for livestock, it is palatable and has high nutritive value (Schultze-Kraft et al., 1992). Congo grass is mainly used for direct grazing in permanent pastures in open or under coconut plantations. Congo grass can also be cut to be made into hay or fed fresh to stalled ruminants (Cook et al., 2005; Schultze-Kraft et al., 1992). There is increasing interest in growing Congo grass both for fodder and for mulch in soybean-maize associations or in sunflower crop in Brazil (Giancotti et al., 2015Ceccon et al., 2014).

Distribution 

Congo grass is native to the Ruzizi valley in Eastern Zaire, Rwanda and Burundi (Schultze-Kraft et al., 1992). In East Africa, Congo grass is one of most important representant, with Signal grass (Brachiaria brizantha) and Para grass (Brachiaria mutica) of the Brachiaria genus (Urio et al., 1988). Though not as persistant as signal grass, Ruzi grass is the main Brachiaria grown in Thailand because seed production is easier (Partridge, 2003).

Congo grass is naturalized in most humid tropics (West-Central Africa, Indian Ocean, South-East Asia, the Pacific region and many countries of South and Western Meso-America and also Brazil (Clayton et al., 2006; Schultze-Kraft et al., 1992). Congo grass is common as a pioneer species of cleared rain forest in Africa (Ecoport, 2014)

Congo grass is generally found in grasslands from sea level up to an altitude of 2000 m in the humid tropics of Africa and up to 1200 m altitude in Panama (FAO, 2015). It can grow in places where annual rainfall is at least 1200 mm with a dry season of no more than 4-5 months (Cook et al., 2005; Schultze-Kraft et al., 1992). Temperatures can range from 19°C to 33°C. Optimal growth is obtained when day/night temperatures are 33°C/28°C. Congo grass has no frost tolerance and moderate shade tolerance. Congo grass does better in well drained fertile soils such light to loam soils with pH ranging from 5 to 6.8 (Cook et al., 2005). Congo grass has poor tolerance of flooding conditions. Some genotypes of Congo grass were however found to have some Aluminium tolerance in Brazil (Miguel et al., 2011).

Forage management 

Yield

Congo grass is a summer growing species yielding high amounts of biomass under high nitrogen supply. DM yield could exceed 20 t/ha in Australia and South America and up to 25 t DM/ha in Sri Lanka under 366kg N/ha fertilizer (Husson et al., 2008; Cook et al., 2005). In low fertile soils of Coronel Pacheco (Brazil) with no N fertilizer, Congo grass yielded only 6 t DM/ha. The biomass production could be up to 12 t DM/ha after 150 kg N fertilizer application (Cook et al., 2005). Biomass production is at its highest level during the second year of establishment.

Forage management

Congo grass can be propagated both from root stock as well as from seeds (Urio et al., 1988). If propagation by seeds is intended, the dormancy of seeds will be stopped after 6 months storage after harvest. or by chemical scarification (

Seeds can be broadcast on a well-prepared seedbed and should not be buried deeper than 2 cm. Congo grass seedling vigour is high and thus prevents weed development (Husson et al., 2008). If Congo grass is vegetatively propagated, stem cuttings with rooting nodes are necessary. Congo grass requires good fertility status, it is thus important to provide N, P and K fertilizers prior to planting  and along grass growth (Cook et al., 2005).

Once it is established, and provided it receives enough N fertilizer, Congo grass spreads readily. Congo grass flowers later than signal grass (Schultze-Kraft et al., 1992). It should be cut before first flowering and then at six week intervals (ILRI, 2013). When grazed, Congo grass withstands moderately heavy grazing (Cook et al., 2005).

Association with legumes

Congo grass can be grown in association with a wide range of legumes such as stylo (Stylosanthes guianensis), puero (Pueraria phaseoloides), greenleaf desmodium (Desmodium intortum), centro (Centrosema molle) or leucaena (Leucaena leucocephala). In association, congo grass should be heavily grazed so that the sward become open and allow legumes to establish and persist (Cook et al., 2005).

When grown in associtation with Stylo, it can be harvested together to make good quality silage (FAO, 2015). It was also possible to make pure Congo grass silage with formic acid addition, best quality was obtained at 2 l formic acid/tonne of fresh Congo grass (Lowilai et al., 2002)

Environmental impact 

Cover crop, erosion and weed controller, soil conditionner

Congo grass can both provide fodder to livestock and good mulch stuff in no-till soybean plantations, or no-till soybean-maize crop successions, in Brazil (Ceccon et al., 2014; Lima et al., 2014). It was assessed in no-till sunflower crops where its high sensitivity to glyphosate provided quick dessication and its high C/N ratio allowed the mulch to remain as a soil cover during an extended period (Giancotti et al., 2015).

Congo grass has been used to control erosion in different situations. When used to make contour hedgerows around cassava crop in Asian hills, it was however found to decrease cassava yields (Howeler et al., 1998).

Congo grass was also used as a cover crop that could decrease soil temperature and conserve soil moisture, two important points for coffee trees that decrease their yield at temperatures above 30°C (Coffee and Climate, 2015).

Soil nutrients recycling and phosphorus availabililty enhancer

Congo grass has valuable nutrients recycling activity and enhances soil properties (Calonego et al., 2013; Garcia et al., 2013). Congo grass was reported to decrease soil P fixation through acid phosphatase activity and P metabolizing micro-organism promotion (Janegitz et al., 2013). It subsequently enhances soil P availability for the next crops (Janegitz et al., 2013).

Nutritional aspects
Potential constraints 

Photosensitization

Though less frequent than in Signal grass, some cases of photosensitization have been recorded. Mortality rates could reach 20-60% in light-skinned sheep grazing pastures dominated by Congo grass in 1980 and 1981. The sheep developed generalized necrosis and severe icterus (Pierre, 1984). Other outbreaks of hepatogenous photosensitization of sheep have been recorded in Brazil (Nazario et al., 1985 cited by Riet-Correa et al., 2011; Purchio et al., 1988).

Ruminants 

Cultivated in the humid tropics for pasture.

Nutritional tables

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

IMPORTANT INFORMATION: This datasheet is pending revision and updating; its contents are currently derived from FAO's Animal Feed Resources Information System (1991-2002) and from Bo Göhl's Tropical Feeds (1976-1982).

Main analysis Unit Avg SD Min Max Nb
Dry matter % as fed 25.1 7.1 15.3 46.9 247
Crude protein % DM 9.0 3.1 3.3 14.5 302
Crude fibre % DM 33.1 3.4 27.6 40.6 300
NDF % DM 67.7 65.5 74.8 2 *
ADF % DM 39.0 2.6 31.9 40.1 10 *
Lignin % DM 5.5 0.6 3.9 5.7 10 *
Ether extract % DM 2.0 0.5 1.2 3.3 293
Ash % DM 9.5 1.8 6.3 13.3 300
Gross energy MJ/kg DM 18.0 *
 
Minerals Unit Avg SD Min Max Nb
Calcium g/kg DM 4.3 0.9 2.4 6.2 298
Phosphorus g/kg DM 2.2 0.9 1.0 4.4 298
Potassium g/kg DM 24.4 7.0 10.9 38.0 246
Sodium g/kg DM 0.9 0.4 1.4 2
Magnesium g/kg DM 2.8 0.7 1.6 4.3 242
Manganese mg/kg DM 49 18 39 70 3
Zinc mg/kg DM 38 10 29 48 3
Copper mg/kg DM 5 3 3 8 3
 
Ruminant nutritive values Unit Avg SD Min Max Nb
OM digestibility, Ruminant % 55.6 *
Energy digestibility, ruminants % 53.2 *
DE ruminants MJ/kg DM 9.6 *
ME ruminants MJ/kg DM 7.7 *
Nitrogen digestibility, ruminants % 69.2 1

The asterisk * indicates that the average value was obtained by an equation.

References

Abaunza et al., 1991; CIRAD, 1991; INFIC, 1978; Nasrullah et al., 2003; Pozy et al., 1996; Scaut, 1959

Last updated on 27/11/2012 14:24:25

Main analysis Unit Avg SD Min Max Nb
Dry matter % as fed 89.2 4.0 81.6 94.2 36
Crude protein % DM 4.7 0.8 3.4 6.3 36
Crude fibre % DM 38.2 2.1 33.7 42.7 36
NDF % DM 70.6 *
ADF % DM 44.6 *
Lignin % DM 6.9 *
Ether extract % DM 1.2 0.2 0.8 1.5 36
Ash % DM 8.3 1.6 5.3 10.8 36
Gross energy MJ/kg DM 18.0 18.0 19.2 2 *
 
Minerals Unit Avg SD Min Max Nb
Calcium g/kg DM 4.4 0.6 3.1 5.4 36
Phosphorus g/kg DM 1.7 0.6 0.7 2.6 36
Potassium g/kg DM 21.3 5.5 10.1 31.3 36
Sodium g/kg DM 0.1 1
Magnesium g/kg DM 2.1 0.5 1.5 3.3 36
Manganese mg/kg DM 153 1
Zinc mg/kg DM 23 1
Copper mg/kg DM 4 1
 
Ruminant nutritive values Unit Avg SD Min Max Nb
OM digestibility, Ruminant % 46.0 *
Energy digestibility, ruminants % 44.0 *
DE ruminants MJ/kg DM 7.9 *
ME ruminants MJ/kg DM 6.4 *

The asterisk * indicates that the average value was obtained by an equation.

References

CIRAD, 1991

Last updated on 27/11/2012 14:28:24

Main analysis Unit Avg SD Min Max Nb
Dry matter % as fed 70.9 12.8 59.6 90.3 5
Crude protein % DM 11.5 0.3 11.1 11.9 5
Crude fibre % DM 16.0 1.7 14.2 18.0 5
NDF % DM 48.2 *
ADF % DM 17.2 *
Ether extract % DM 8.6 0.4 8.1 9.1 5
Ash % DM 4.4 0.4 3.8 4.9 5
Gross energy MJ/kg DM 19.7 *
 
Minerals Unit Avg SD Min Max Nb
Calcium g/kg DM 1.2 0.7 0.4 2.0 5
Phosphorus g/kg DM 2.8 0.2 2.4 3.0 5
Potassium g/kg DM 6.2 1.7 4.0 8.0 5
Magnesium g/kg DM 1.7 0.2 1.5 1.9 5
 
Ruminant nutritive values Unit Avg SD Min Max Nb
OM digestibility, Ruminant % 62.7 *
Energy digestibility, ruminants % 61.2 *
DE ruminants MJ/kg DM 12.1 *
ME ruminants MJ/kg DM 9.9 *
 
Pig nutritive values Unit Avg SD Min Max Nb
Energy digestibility, growing pig % 65.0 *
DE growing pig MJ/kg DM 12.8 *

The asterisk * indicates that the average value was obtained by an equation.

References

CIRAD, 1991

Last updated on 24/10/2012 00:45:31

References
References 
Datasheet citation 

DATASHEET UNDER CONSTRUCTION. DO NOT QUOTE. http://www.feedipedia.org/node/484 Last updated on April 24, 2015, 10:02

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