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Acroceras macrum Stapf

Poaceae
Nile Grass

Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.

  1. Uses
  2. Folk Medicine
  3. Chemistry
  4. Description
  5. Germplasm
  6. Distribution
  7. Ecology
  8. Cultivation
  9. Harvesting
  10. Yields and Economics
  11. Energy
  12. Biotic Factors
  13. References

Uses

A very palatable grass and rather extensively cultivated as pasture and hay, especially in the highyield areas of South Africa. Forms dense cover used for grazing and haymaking. Unsuitable for leys, as it is difficult to eradicate. Very useful as fodder source during dry season. The grass has been described, perhaps hyperbolically, as "the king of fodder grasses—a truly revolutionary grass" (Rhind and Goodenough, 1979).

Folk Medicine

No data available.

Chemistry

Per 100 g, the forage is reported to contain 8.7 g protein, nearly 6 g fat, 75.4 g total carbohydrate, 30.7 g fiber, 450 mg Ca, and 110 mg P (Bogdan, 1977). Other reports put the crude protein as high as 22%; one report gives 21.3% for leaves, and 7.9% for the stems; crude fiber was given as 30.0% for leaves, 38.5% for stems. On a zero moisture basis, South African hay was 8.5% CP, 31.8% CF, 6.1% ash, 1.8% EE and 51.8% NFE (Gohl, 1981). Many more nutritional details are tabulated in the excellent review by Rhind and Goodenough (1979).

Description

Perennial grass, spreading by creeping slender rhizomes and stolons; culms up to 70 cm or more, sometimes prostrate at base; leaves expanded, to 20 cm long and 12 mm broad, glabrous or minutely hairy, rounded or almost cordate at base, tapering to sharp point, bright green; panicle up to 20 cm long, spikelike, of 2–5 racemes up to 8 cm long, the lower 5–9 cm apart; spikelets light green, acuminate or obtuse, 4–5 mm long, awnless, glabrous, with conspicuous indurate rounded appendages at laterally compressed apex of glumes and lemmas; lower glume more than half as long as spikelet, 3-nerved; upper glume 5-nerved; ligule a membrane fringed with short hairs, sometimes greatly reduced. 4x = 36.

Germplasm

Reported from the Africa Center of Diversity, Nile grass or cvs thereof is reported to tolerate low pH, photoperiod, sand, savanna, virus, and waterlogging. It does not tolerate drought very well. Susceptibility to diseases and an apparent lack of seed-setting ability were partially overcomeby breeding programs initiated at Cedara. Tetraploid (2n= 36), pentaploid (2n= 45), and hexaploid (2n= 54) chromosome races occur. The species is self sterile, but certain combinations of strains of similar chromosome number and flowering data highly cross fertile (Rhind and Goodenough, 1976). (2n= 36)

Distribution

Widely distributed in Africa from Ethiopia to South Africa, also in Angola and South West Africa; introduced elsewhere e.g., Australia, Surinam, and Trinidad.

Ecology

Grows naturally in seasonally flooded valley bottoms in areas with 92–150 cm rainfall annually. It is indifferent to day length and will flower equally readily in long or short photoperiods. Flourishes on poorly drained or seasonally flooded land, and does not grow well under dry conditions. It has been successful on loams, sandy loams, and clay loams. Ranging from Warm Temperate Dry through Tropical Moist Forest Life Zones, Nile grass is reported to tolerate annual precipitation of 8 to 27 dm (mean of 4 cases = 13), annual temperature of 16° to 26°C (mean of 4 cases = 17), and pH of 4.3 to 7.3 (mean of 4 cases = 5.5). Rhind and Goodenough (1979) say it favors areas at elevation ca 600 to 2000 m, annual precipitation of 7.5–15 dm where the dry season is not too long.

Cultivation

Propagated by splits or cuttings of rhizomes or stolons. In some areas under humid conditions, grass is cut at hay stage and scattered over surface of land and then covered by a disc-harrow, as in Trinidad. Planted in holes 45 x 45 cm apart. Grass should be alllowed a full year to become established. Although its growth habit, having both rhizomes and stolons, serves for vegetative propagation and for exploring new ground, it also allows for carbohydrate storage in the rhizomes and brings some of the growing points below ground level where they are more effectively protected from frost, drought and burning. Has been used for improving natural moist pastures by planting splits or rhizome cuttings into existing natural grassland or plowed grassland following an arable crop. It was persistent although not very productive in Kenya and South Africa, and was reasonably successful in Rhodesia, Surinam and Swaziland (Bogdan, 1977). Seeds have a dormancy characteristic, germination improving after 9 months storage.

Harvesting

Grazed or cut for hay. Grass should be mown towards end of rainy season (summer) for hay or silage. Good aftermath is available for grazing during dry autumn and winter months when it is most valuable. A further flush can be grazed in spring during the early season.

Yields and Economics

Cut for hay, it yields 5–8 MT/ha (Bogdan, 1977). In one Rhodesian trial, it was one of the lowest yielders, at 7 MT/ha. Yields may attain 12.5 T/ha per season. In Natal, it averaged 9.8 MT/ha/a for three seasons (Theron and Arnott, 1979). A valuable pasture and fodder grass in areas of adaptation especially in humid tropical areas, as South Africa.

Energy

According to the phytomass files (Duke, 1981), annual productivity ranges from 4 to 12 MT/ha. Rhind and Goodenough (1979) report 2 to 18 MT DM (the latter is Swaziland). Such DM (dry matter) can be converted to energy by burning or conversion to alcohol or methane. According to Gohl (1981), ME (metabolizable energy) is 2.35 megacalories per kilogram of dry matter in hay.

Biotic Factors

The fungi, Phyllosticta sp. (leaf spot) and Ustilago syntherismae (smut) have been reported on this grass.

References

Complete list of references for Duke, Handbook of Energy Crops
Last update December 19, 1997