Andropogon gayanus Kunth
Source: James A. Duke. 1983. Handbook of Energy Crops. unpublished.
- Folk Medicine
- Yields and Economics
- Biotic Factors
Considered one of the best grazing grasses in northern Nigeria and
northern Ghana. Makes valuable hay and green fodder grass in central and
northeastern Brazil. In Africa, this grass grows in large tufts up to 2 m
tall. Young shoots are preferred, but cattle will eat it up to time of
flowering. Stems, flattened, are used for coarse matting (weaving grass mats
and thatching). Plants are useful for planting on banks for erosion control.
No data uncovered.
On a zero moisture basis, fresh Ghanan grass (19.9% DM) contains 12.9%
CP, 25.6% CF, and 8.5% ash; the same (24 weeks old) (59.4% DM) contains 5.4%
CP, 29.9% CF, and 5.5 % ash. Nigerian hay (88.5% DM) contains 6.1% CP, 35.1%
CF, 7.9% ash, 1.7% EE, and 49.2% NFE, while silage (DM 25.0%) contains 5.8% CP,
37.4% CF, 7.4% ash, 1.9% EE, and 47.5% NFE (Gohl, 1981).
Tall annual or perennial, tussock grass; culms erect, up to 3 m tall,
more or less stout, about 0.6 cm in diameter, glabrous, many-noded, producing
flowering branches from the third node upward; leaves glabrous or softly
pubescent, rarely villous or tomentose; sheath tight, striate; ligule short,
rounded or truncate, glabrous or somewhat hairy on back, rarely exceeding 0.2
cm long; lamina linear to lanceolate-linear in the lower leaves, usually from a
much attenuated base and there often forming a terete petiole, tapering to a
fine point, over 30 cm long, up to 1.6 cm broad, glaucescent or reddish, margin
scabrous; inflorescence in panicles up to 6 or more primary mixed 2 to many
rayed tiers, the inner ray of lower or lowest tiers often up to 30 cm long
(sometimes up to 60 cm long), with 24 secondary few-rayed tiers; spatheoles
pale green, herbaceous, lanceolate-oblong, 6.57.5 cm long, at length more or
less tightly enrolled and turning red; racemes in pairs, 3.56.5 cm long, one
sessile, the other with a bare base about 0.4 cm long, joints stout,
cuneate-clubshaped; sessile spikelets greenish or tipped brown or red, about
0.8 cm long including the obtuse callus; scantily bearded at base; glumes
equal; awn 1.32.2 cm long, twisted well below middle, column brown, bristle
pale; pedicellate spikelets male and glabrous. Fl. AprilJune in tropical
Several varieties are recognized: var. gayaunus with pedicelled
spikelets glabrous, the joints and pedicles ciliate on one margin only; var.
squamulatus, with pedicelled spikelets scaberulous, the joints and
pedicels ciliate on both margins; var. argyophoeus, with pedicelled
spikelets plumosely villous, basal leaves villous; var. bisquamulatus,
with pedicelled spikelets not so hairy, basal leaves not villous.
Squamulatus and bisquamulatus are "dry ground" varieties which
grow best on well-drained sandy clays of medium to high fertility (Bowden,
1963). Reported from the Africa Center of Diversity, gamba grass or cvs
thereof is reported to tolerate drought, fire, frost, high pH, heavy soil, low
pH, poor soil, savanna, slope, and waterlogging. Var. gayanus is more
likely to tolerate waterlogging and frosts than the "dry-land" varieties (Duke,
1978). (2n = 20, 40, 44)
Native and widely distributed in tropical Africa, north and south of
Equator; introduced to other tropical areas, as tropical Queensland, Brazil,
India, and western Australia.
Ranging from Warm Temperate Moist through Tropical Dry to Wet Forest
Life Zones, gamba grass is reported to tolerate annual, precipitation of 8 to
27 dm (mean of 9 cases = 12.2), annual temperature of 15 to 32°C (mean of 9
cases 21.4), and pH of 4.3 to 8.3 (mean of 5 cases = 6.1). In grassy places,
damp places, low-lying meadows, edge of thickets; often forming large areas.
Also thrives in areas with long dry season up to 7 months long. Adapted to a
wide range of soil types, with different ecotypes adapted to various soils
varying from sandy to heavy black cracking clays. Very drought resistant and
not to susceptible to frost.
Propagated by seed. Caryopses germinate better with chaff removed and
covered over by soil or sand. Clean seedbed required, but sowing should not be
delayed more than 2 months after beginning of rains (in India). It is often
under-sown in corn, sesame or millet. Seeding rate varies: in Brazil, 5 kg/ha;
in Nigeria, 3570 kg/ha, of uncleaned seed. Seed production is often very low.
Sometimes grown in mixture with Clitoria ternatea in tropical Australia.
May also be propagated by splints, those from mature woody stumps doing best
(Bowden, 1963). Highest return of dry matter per unit N (14.4 kg DM/kg N)
occurred at 28 kg N/ha; CP content increased only modestly as N was increased,
reaching a maximum 10.5% with the highest N level. At higher levels of N,
A. gayanus was replaced by less desirable grasses (Haggar, 1974).
Bogdan (1977) reports trebling of yields with 100 kg N/ha and double to treble
with 20 MT fym/ha.
Plants persist well under grazing, but are only palatable before
flowering. The flowering stems, which are produced in quantity, are hard and
should be removed by mowing or burning. Frequent burning tends to suppress
this grass and allows it to be replaced by less useful species. In one
experiment (Bowden, 1963) over three years, plots were cut only when grass
reached 6, 9, 12 and 15 dm, necessitating 12, 9, 8 and 7 cuts respectively.
The taller the grass when cut, the higher the annual DM yield. Plants grown in
rows gave more DM, CP and soluble carbohydrate than plants grown in swards.
Haggar (1974) reported yields of 27 MT in 1964, 1012 in 1965, and 612
in 1966, at 0 to ca 200 kg/N/ha respectively. According to Bogdan (1977), this
is one of the high yielding grasses of West Africa, being outyielded by
Melinis minutiflora, Panicum maximum and/or Pennisetum
purpureum. Fresh fodder yield of 57 MT are recorded from India, 76 from
Mali. From the Cameroons, DM yields of 7.17.8 MT/ha, 4 MT/DM from Australia,
and 2.48.6 MT elsewhere (Bogdan, 1977). Seed yields up to 30 kg/ha per cut
with 3 cuts per year have been recorded in Brazil. In pure stands in Ghana,
dry matter yields per harvest from March 12 to November 12 (in 5 harvests)
averages 7,478 kg/ha, with total harvest being 37,391.35 kg/ha. In
Andropogon-Desmodium stands 34,334 kg/ha; in Andropogon-Centrosema, 30,397.45
kg/ha (Tetteh, 1972). Widely cultivated and used grass used in tropical Africa
(Nigeria and Ghana), Brazil, India, and Australia for fodder, grazing, hay and
to some extent for erosion control.
According to the phytomass files (Duke, 1981b), annual productivity
ranges from 4 to 25 MT/ha. According to Gohl, the ME (metabolizable energy)
for cattle ranges from 1.71 megacalories/kg DM in silage to 1.65 in hay, 2.02
in mature forage and 2.33 in early vegetative forage.
Following fungi have been reported on this grass: Fusarium
moniliforme (on seed), Phyllachora assimilis, Puccinia erythraeensis, P.
versicolor, Sphacelotheca andropogonis, S. ischaemicola. Nematodes
isolated from this grass include: Criconemella sp., Helicotylenchus
cavenessi, R. pseudorobustus, Memicriconemoides cocophilus, Hemicycliophora
oostenbrinki, Scutellonema clathricaudatum, Tylenchorhynchus annulatus,
Xiphinema ebriense, and X. nigeriense.
Complete list of references for Duke, Handbook of Energy Crops
- Bogdan, A.V. 1969. Rhodes grass. Commonwealth Bureau of Pastures and
Field Crops, Hurley, Berkshire, England, Herbage Abstracts 39(1):113.
- Bowden, B.N. 1963., Studies on Andropogon gayanus Kunth. I. The
use of Andropogan gayanus in agriculture. Empire J. Exper. Agric.
- Duke, J.A. 1978. The quest for tolerant germplasm. p. 161. In: ASA Special
Symposium 32, Crop tolerance to suboptimal land conditions. Am. Soc. Agron.
- Duke, J.A. 1981b. The gene revolution. Paper 1. p. 89150. In: Office of
Technology Assessment, Background papers for innovative biological technologies
for lesser developed countries. USGPO. Washington.
- Gohl, B. 1981. Tropical feeds. Feed information summaries and nutritive values.
FAO Animal Production and Health Series 12. FAO, Rome.
- Hagger, R.J. 1974. The effect of quantity, source, and time of application of
nitrogen fertilizers on the yield and quality of Andropogon gayanus at
Shika, Nigeria. J. Agr. Sci. Cambr. 84:529535.
- Tetteh, A. 1972. Comparative dry matter yield patterns of grass/legume mixtures
and pure stands (Andropogon gayanus, Digitaria decumbens,
Centrosema pubescens, Desmodium leiocarpum). Ghana J. Agr. Sci.
Last update December 22, 1997