Cenchrus ciliaris (PROSEA)
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Introduction |
- Protologue: Mant. pl. alt.: 302 (1771).
- Family: Gramineae
- Chromosome number: 2n= 32, 34, 36 (tetraploid), 40, 52, 54
Synonyms
Pennisetum cenchroides Rich. (1805), P. ciliare (L.) Link (1827).
Vernacular names
- Buffelgrass (Australia) (En). African foxtail (Am)
- Philippines: kawit-kawitan (Tagalog), sagisi (Ilokano)
- Thailand: ya-bupfen.
Origin and geographic distribution
Buffulgrass naturally occurs throughout Africa and from Arabia and the Middle East to India. It has been widely introduced and is naturalized throughout the semi-arid and sub-humid tropics and subtropics
Uses
The main use of buffelgrass is as a pasture grass for ruminants and horses. It is usually grazed, but can be used as silage or hay.
Properties
The N concentration of green buffelgrass ranges from 1.0% to 3.0% of the dry matter, depending on growth stage, soil fertility, fertilization rate and cultivar. Phosphorus concentration is usually adequate for animal requirements and higher than that of most other tropical grasses, with published values up to 0.65% of the DM. The DM digestibility of green buffelgrass leaves ranges from 65-70%. Buffelgrass is highly palatable to all kinds of grazing animals.
Horses eating this grass can develop a calcium deficiency syndrome ("bighead disease") caused by soluble oxalate (concentrations of 1-2% of the DM have been recorded). Variation in the diet or supplementation with limestone or dolomite will control it. Ruminants are able to break down the oxalate in the rumen, although occasionally toxicity symptoms have been recorded with sheep and cows.
There are 90-1200 fascicles/g. A fascicle is a cluster of spikelets which may contain one to five caryopses, making up 25-30% of the fascicle weight.
Description
A tufted or rarely spreading perennial, often with short rhizomes. Culm 10-150 cm tall, erect or ascending, branching and rooting at the nodes. Leaf-sheath compressed; ligule a hairy ring, up to 1.5 mm tall; leaf-blade linear, 3-30 cm × 2-13 mm, glabrous, but hairy at the mouth. Inflorescence a cylindrical to ovoid panicle, 2-14 cm × 1-2.6 cm, grey, purple or straw-coloured, bearing numerous clusters of spikelets (fascicles), each fascicle surrounded by an elongated involucre of bristles 6-16 mm long; rachis angular and puberulous; inner bristles much exceeding the spikelets, somewhat flattened and connate at the base, ciliate below, one of them longer and stouter than the rest; outer bristles shorter, filiform; spikelets 1-4 per cluster, acutely lanceolate, 2-5.5 mm long, sessile; glumes distinct, acute, upper ones up to as long as the spikelet; lemmas subequal, 2.5-5 mm long, minutely awned. Caryopsis ovoid, 1.5-2 mm × 1 mm.
Growth and development
Buffelgrass seed germination rate can be as low as 15% soon after harvest, when the caryopses remain within the fascicles, but over 90% germination has been measured. Naked caryopses have a higher germination rate, but seedlings are then more sensitive to drought. Glumes contain water-soluble germination inhibitors, which is the main cause of the seed dormancy.
Germination rate improves with storage of 6-18 months. Seedling growth rate is relatively slow. Buffelgrass has a deep root system with coarse roots. Maximum rate of tiller formation occurs just after first inflorescence appearance; tillering is sustained at a reduced rate during seed maturation. Buffelgrass is an early flowering short-day plant with an optimal photoperiod of 12 hours.
Other botanical information
Most cultivars are developed in Australia: "Biloela" (tall growing, rhizomatous, greyish leaves), "Nunbank" (similar to "Biloela"), "Boorarra" (similar to "Biloela", but less rhizomatous), "Tarewinnebar" (similar to "Biloela", but with green leaves), "Molopo" (tall growing with a lower tiller density, more rhizomatous and distinctly glaucous leaves, more greyish), "Lawes" (similar to "Molopo"), "Gayndah" (short, semi-prostrate to ascending, non-rhizomatous), "American" (short, similar to "Gayndah"), "West Australian" (short, non-rhizomatous, least productive, highly palatable, most drought tolerant). Cultivars are very homogeneous, because buffelgrass is an apomict, although there is a small percentage of sexual seed production. "Higgings grass" was developed from a single sexual plant in Texas. There are also some African cultivars.
Ecology
Buffelgrass grows best in climates with 300-750 mm annual summer-dominant rainfall. Nevertheless it also grows well in the Philippines on 1600-2900 mm annual rainfall. Optimum temperature is about 35 °C and minimum temperature between 5-16 °C. Buffelgrass prefers free-draining, light-textured neutral to alkaline soils (pH(H2O)>6.0). "American" is more tolerant to acid soils than the other cultivars. The more rhizomatous cultivars also grow well on many clay soils.
Buffelgrass is sensitive to soils containing high levels of Al, has a moderate tolerance to salinity and is intolerant of flooding. It tolerates fire.
Propagation and planting
Seed dormancy can be broken by high temperatures (60 °C) for 4-12 weeks, by removal of the hulls of the fascicle by hammermilling, or by storing the seed for up to 18 months. Treatment of the seed with sulphuric acid also improves germination. Seeds are not easy to clean; hammermilling to pulverize stems and bristles improves seed handling and sowing. The seed can be sown in soil without or with light tillage, on the surface followed by rolling, but germination is best when sown at a depth of 1-2 cm. Suggested seed rates vary from 0.5 kg/ha of caryopses to 12 kg/ha of fascicles; good results have been obtained with 4 kg/ha of fascicles.
Sowing whole fascicles is preferred to sowing naked caryopses. In India vegetative propagation from tuft splits or replanting of young plants sown in a nursery has also been advocated.
Buffelgrass can be grown in association with Stylosanthes hamata (L.) Taub., Macroptilium atropurpureum (DC.) Urban, Chloris gayana Kunth and Panicum maximum Jacq. var. trichoglume Robijns.
Husbandry
Buffelgrass grown as a sole crop is usually not fertilized, although it responds well to P and N fertilizer.
When grown in association with a legume, fertilization with superphosphate is beneficial on poor soils. Irrigation is not usual or necessary as the grass is drought tolerant.
Diseases and pests
Buffelgrass is quite free of diseases or pests. In wetter areas the seed can be destroyed by ergot or smut.
Harvesting
First harvest of buffelgrass can be 4-6 months after sowing by cutting or grazing. Suggested cutting height is about 7 cm above ground level, with 6-8 week intervals. For hay, buffelgrass is usually cut in the early flowering stage. Buffelgrass can be grazed continuously or rotationally.
Yield
Dry matter yields range from 2-9 t/ha per year without fertilizer and up to 24 t/ha per year with complete fertilizer. Seed production depends on cultivar and growing conditions and recorded (fascicle) yields range from 150-500 kg/ha. Mean liveweight gains of steers of 160 kg/annum grazing buffelgrass pastures with Macroptilium purpureum at 1 steer/ha have been recorded in a sub-humid subtropical climate in south-east Queensland.
Genetic resources
A large collection of buffelgrass germplasm is held at ATFGRC (CSIRO, Australia).
Breeding
The apomixis of buffelgrass is linked with pseudogamy. Hybridization is possible because of the discovery of a rare fertile female. Male pollen from the apomictic lines are used to fertilize the rare fertile female with consequent release of much variation. A selection programme is in progress at CSIRO, Brisbane, Australia with the objectives of developing cultivars of better quality forage and better spring vigour.
Prospects
Buffelgrass has little prospect in humid climates, but can play a major role in forage production in areas with a dry season in South-East Asia.
Literature
- Bogdan, A.V., 1977. Tropical pasture and fodder plants (grasses and legumes). Longman, London and New York. pp. 66-74.
- Clayton, W.D. & Renvoize, S.A., 1982. Gramineae (Part 3). In: Polhill, R.M. (Editor): Flora of tropical East Africa. A.A. Balkema, Rotterdam. pp. 691-692.
- Hacker, J.B., 1989. The potential for buffelgrass renewal from seed in 16-year-old buffelgrass-siratro pastures in south-east Queensland. Journal of Applied Ecology 26: 213-222.
- Humphreys, R.L., 1967. Buffelgrass in Australia. Tropical Grasslands 1: 123-134.
- Rudolf, I.G.W., Blair, G., Orchard, P.W., Till, A.R. & Hunt, M., 1988. The performance of Ongole heifers grazing native and introduced pasture species at Sumba, Indonesia. Journal of Agricultural Science (United Kingdom) 111: 11-17.
- Skerman, P.J. & Riveros, F., 1990. Tropical grasses. FAO, Rome. pp. 266-274.
- 't Mannetje, L. & Jones, R.M., 1990. Pasture and animal productivity of buffelgrass with siratro, lucerne or nitrogen fertilizer. Tropical Grasslands 24: 269-281.
Authors
L. 't Mannetje & S.M.M. Kersten
