Brachiaria eminii Mez.
Kennedy ruzi grass (Australia), Congo signal grass (Africa), prostrate signal grass (Kenya).
A spreading perennial with short rhizomes, similar in habit to Para grass. The inflorescence consists of dense and spikelike racemes. The spikelets are all sessile and close together, the rachis of the racemes winged, broad and over 3 mm wide. The spikelets are hairy and the lower glume under half the length of the spikelet (Harker & Napper, 1960). It has softer leaves than B. brizantha.
Lake Edward and Lake Kivu districts, Rwanda, Burundi, and the Ruzizi plains in Zaire, now widely distributed in the tropics.
1 000-2 000 m in Kenya, up to 1 200 m in Panama (Rattray, 1973).
It requires a reasonably high rainfall, but can endure hot dry spells. A rainfall of 1 000 mm or more is best.
It has good drought tolerance.
It requires a soil of high fertility, such as latosols carrying mesophyll rain forest. It will tolerate acid soils. It needs good drainage.
It spreads well from rhizomes.
A well-prepared seed-bed is recommended, but light disc-harrowing gives good results.
Drill the seed into a well-prepared seed-bed. In Zaire it has been sown in rows 60 cm apart, or broadcast over the land after scarification of the soil with a disc harrow or brushcutter, without burning the native pastures, and grazed as soon as it is ready (Risopoulos, 1966).
Surface sow in moist soil, and sow no deeper than 2 cm in dry soil (Bogdan, 1964). In Zaire it is recommended to sow at a depth of 1-2 cm. Under humid conditions seeds lose their vitality after one year (Risopoulos, 1966).
In Zaire the seed rate recommended is 30 kg/ha.
About 250 000.
Excellent (Davidson, 1966).
It gives good early wet season growth for eight weeks after the opening rains (Falvey, 1976) and it seeds heavily in April at South Johnstone, north Queensland (lat. 17°36'S).
It forms a dense mat under grazing which withstands grazing well (Davidson, 1966). The yields of dry matter did not vary very significantly in Sri Lanka with monthly cutting at 2.5 cm or 7.6 cm but bimonthly cuts yielded a little higher (Appadurai & Goonawardene, 1973).
In combination with Stylosanthes humilis in northern Australia it must be grazed heavily to maintain this legume in the sward (Falvey, 1976).
Selection 6019 at CIAT, Colombia, does not tolerate fire (CIAT, 1978).
It made very good silage with Stylosanthes guianensis in Zaire with 1 percent molasses and without additive (Risopoulos, 1966) and made good hay in Zambia (van Rensburg, 1969).
No toxicity has been recorded by Everist (1974).
A seed yield of 125 kg/ha has been recorded in Queensland and 200 kg/ha in Zaire (Risopoulos, 1966).
'Kennedy', described above, is the only present cultivar. Selection 6019 has been tested at CIAT, Colombia.
It is comparatively free from diseases.
Its fast growth early in the wet season, its compatibility with Stylosanthes humilis and S. hamata, its good seed production and ease of establishment.
Its winter growth is slow. It needs well-drained fertile soils.
33°C day, 28°C night (Dienum & Dirven, 1972).0
Low yields resulted from a 24/19°C regime. Ludlow (1976) found this species, of several tropical grasses, the most affected by low temperatures.
It is killed by heavy frosts, and spring regrowth is very slow after light frosts.
Yields increase with increasing light intensity (Dienum & Dirven, 1972).
It successfully suppresses weeds.
The seed is germinated at 20-35°C after treatment with sulphuric acid for ten minutes. Fifteen percent germinable seed and 40 percent purity in Queensland.
There are few pests.
It is very palatable. At the Cerrado Centre, Brazil, it was preferentially grazed ahead of Stylosanthes guianensis during the rainy season.
High temperatures have an adverse effect on digestibility (Dienum & Dirven, 1972). Digestibility decreased in 18-day material from 78.4 percent at day/night temperatures of 24/18°C to 72.7 percent at 29/30°C and 69.5 percent at 34/30°C (Dirven, 1973). Feeding value declined when it seeded heavily at South Johnstone, Queensland, in April (Mellor, Hibberd & Grof, 1973a). Scaut (1959) in Zaire found fresh grass to contain 13.9 percent crude protein, 27.2 percent crude fibre, 9.0 percent ash, 2.3 percent ether extract and 47.6 percent nitrogen-free extract in the dry matter.
A pioneer species of cleared rain forest in Africa.
It does not tolerate flooding.
It needs high phosphorus in the early growth on a wide range of soils. It responds well to nitrogen, either inorganic or from legumes, but its nitrogen requirement exceeds that of Guinea grass, which makes the latter more attractive (Mellor, Hibberd & Grof, 1973b). Risopoulos (1966) recorded an increased yield of 10 739 kg/ha from nitrogen application in Zaire.
Ruzi grass combines well with legumes such as Centrosema pubescens or Pueraria phaseoloides if the mixture is leniently grazed. In Zaire it has combined well with Setaria sphacelata and Stylosanthes guianensis. In northern Australia Stylosanthes humilis and S. hamata can be introduced by cultivating the grass and oversowing the legumes (Falvey, 1979).
It appears to be apomictic.
It seeds heavily at Gandijika, Zaire (lat. 6°45'S with four months dry season) (Risopoulos, 1966). Seed can be harvested in May in Queensland, either by hand or with a tractor-mounted buffer type seed harvester but yields are lower by this method (Davidson, 1966).
An important grazing species in the wetter tropics.
Brahman steers grazing Kennedy ruzi grass at Utchee Creek, north Queensland, gave a poor winter performance on grass in association with legumes compared with the performance on Guinea grass, but nearly equalled Guinea when 27 kg N/ha was applied. Ruzi grass/legume pastures produced 1 157 kg/ha live- weight gain, while ruzi grass plus 200 kg N/ha per year gave 1 513 kg/ha live-weight gain (Mellor, Hibberd & Grof, 1973a).
Davidson, 1966; Dienum & Dirven, 1972; Mellor, Hibberd & Grof, 1973.J
Fresh seed shows post-harvest dormancy and delayed germination. Fresh seed gave 20 percent germination in Queensland, and after 12 months' storage this increased to 40 percent (Davidson, 1966). Dormancy can also be broken by treating the seed with concentrated sulphuric acid for 15 minutes (Barnard, 1969) or mechanical scarification (Jones, 1973).
It is useful for erosion control in areas where it grows well.
In Tanzania, ruzi grass yielded 21 159 kg DM/ ha (Naveh & Anderson, 1967). At South Johnstone, north Queensland it yielded 19 500 kg DM/ha under a six-week cutting interval and an input of 220 kg N/ha/year (Grof & Harding, 1970). In Sri Lanka yields of 16 807, 22 031 and 25 585 kg DM/ha per year with nitrogen applications of 112, 224 and 366 kg N/ha (Appadurai, 1975). In French Guyana the yield was 20 574 kg DM/ha and 1 180 kg/ha crude protein (Borget, 1966) and in Zaire yields of 31 352 kg and 21 468 kg green matter per hectare per year were obtained in successive years, 1958-59, with 100 kg nitrogen and 100 kg superphosphate per hectare per year (Risopoulos, 1966). At Gualaca, Panama, it produced 11 000 kg DM/ha without fertilizer and 27 000 kg DM/ha when fertilized with 600 kg N/ha per year in a rainfall area of 3 997 mm per year.