Hyparrhenia rufa (Nees) Stapf

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Graminae

Common names

Jaragua, faragua or yaragua grass, puntero (South America), veyale (Mali), senbelet (Ethiopia), yellow spike thatching grass (southern Africa).

Description

A very variable perennial from 60-240 cm high. Panicle loose and narrow up to 50 cm long, with slightly spreading or contiguous racemes with shortly hairy or nearly glabrous spikelets 3.5-5 mm long. The rusty brown hairs on the spikelets and the racemes terminally exserted from the spatheoles distinguish it from H. filipendula and H. hirta (Napper, 1965). The flowering stems have little leaf. The sheaths of the leaves enclose about half the length of each internode, giving the culm and banded appearance.

Distribution

Throughout tropical Africa, but widespread in Central and South America.

Altitude range

Sea-level to 2 000 m in Colombia.

Rainfall requirements

600-1 400 mm.

Drought tolerance

Good ­ on retentive soils withstands a dry season of six months in the llanos of Colombia and in Bolivia.

Soil requirements

Spain and Andrew (1977) found that the order of sensitivity to high aluminium soils was Cenchrus ciliaris cv. Biloela, very sensitive, H. rufa, Panicum maximum and Melinis minutiflora, somewhat sensitive, and Paspalum plicatulum and Brachiaria decumbens, relatively insensitive. Prefers black clays and latosols.

Land preparation for establishment

A fully prepared seed-bed gives best results, but it will establish in a rough seed-bed or after a burn in natural grassland.

Sowing methods

The seed is broadcast or sown in 25-40 cm rows on a prepared and fertilized seed-bed. Root-stocks can also be planted, and it can be undersown in maize.

Sowing depth and cover

Broadcast seed and give it a light harrowing. The long, twisted awns on the 'seed' make it difficult to drill.

Sowing time and rate

Sow in Honduras early January to May at 15-20 kg/ha.

Seedling vigour

Selection 601 at CIAT has good seedling vigour.

Vigour of growth and growth rhythm

Growth is retarded when day-length is less than 12 hours, 15 minutes, during the growing season from October to April. Rattray (1973) recorded dry-matter production over a three-year period in Panama.

Response to defoliation

It stands close grazing (Semple, 1970) if applied rotationally and not continuously.

Grazing management

Jaragua grass must be grazed or mown so that the growth at no time reaches a height of more than 15 cm. This is attained in Costa Rica and Honduras by grazing at approximately one beast to 0.8 hectares throughout the year (Hogaboom, 1952). It takes about two years to establish a good stand by broadcasting seed, or four to five months if sown on a well-prepared seed-bed. Do not graze or cut within the first six months. Flowering stands should be mown or burnt. Undergrazing and no burning favour tussock formation and bare ground. A five-paddock system for beef breeding stock, grazing seven days on and 28 days off from June to November, and 14 days on and 56 days off from December to May, is recommended.

Response to fire

It tolerates seasonal burning.

Dry-matter and green-matter yields

At the Naitama Station, Colombia, under a six-week cutting interval and 50 kg N/ha after each cut, leafy herbage accumulated to 75 cm or more, and contained 12-15 percent protein on a dry-matter basis. Dry-matter production averaged 4 500 kg/ha per year (Crowder, Chaverra & Lotero, 1970). In Honduras, 18 704 kg DM/ha was obtained at seven-week cuts when fertilized with 555 kg/ha of 10:15:15 fertilizer (Kemp, Mackenzie & Romney, 1971).°

Suitability for hay and silage

It should be cut for hay and silage before flowering at a height of 60-70 cm and four to five cuts are obtained during a growing season. It has been used for silage in Minas Gerais (Brazil) (Alves & Silva, 1936). It makes good silage, but the fermentation is very slow.

Toxicity

Ndyanabo (1974) recorded 0.85 percent total oxalic acid in the dry matter, but no toxicity.

Diseases

It has good disease resistance.

Main attributes

Its ability to persist, and to produce high live-weight gains under heavy grazing demonstrates its value in African agriculture (Stobbs & Joblin, 1966). A Panicum maximum/Stylosanthes guianensis pasture at Serere gave 19 kg/ha more live-weight gain, but a H. rufa/centro pasture gave 73 more grazing days in the same experiment.

Main deficiencies

It is rather coarse.

Frost tolerance

It is susceptible to frosts.

Ability to compete with weeds

It competes successfully with weeds and smothers them.

Pests

It has no insect problem.

Palatability

It is not very palatable, especially as it approaches maturity (Semple, 1970).

Response to photoperiod

It is a short-day plant.

Chemical analysis and digestibility

In Costa Rica, H. rufa at floral initiation contained 3.65 percent crude protein, 33 percent crude fibre, 33.55 percent nitrogen- free extract, 1.63 percent ether extract and 16.5 percent ash on a 10 percent moisture basis (Gonzalez & Pacheco, 1970). In Panama, cut at six-week intervals, it averaged 6-8 percent crude protein in the wet season and 4-6 percent in the dry season.

Natural habitat

Seasonally flooded grassland and open woodland.

Tolerance to flooding

It stands waterlogging and temporary flooding, but not permanent flooding.

Fertilizer requirements

It gives a positive interaction with nitrogen and phosphorus, with 112 kg nitrogen and 56 kg superphosphate per hectare the most efficient application (Ortega, personal communication). However, it is one of the better grasses under low nitrogen and low phosphorus conditions (CIAT, 1978). It will not tolerate more than 250 kg nitrogen per hectare during the growing period.

Compatibility with other grasses and legumes

It combines well with legumes.

Genetics and reproduction

2n=20, 30, 36, 40 (Fedorov, 1974).

Seed production and harvesting

It produces abundant viable seed from which it is easily established. The stalks are cut off by hand in December (Honduras) in lengths of about 60 cm, dried in the field and then shaken to dislodge the seed, which must then be well dried. Seed germination is about 25 percent, decreasing to practically nil in ten months (Kemp, Mackenzie & Romney, 1971).

Economics

H. rufa is a common native pasture plant throughout East Africa and Latin America, used mainly for beef cattle production. It has similar characteristics to the H. contortus pasture in near-coastal Queensland, without the troublesome awn. It is used in Africa as a coarse thatching grass and as a general purpose straw, and produces a useful pulp for paper.

Animal production

At the El Nus Station, Colombia, on steep slopes, two-year- old steers grazed on unfertilized H. rufa at one or two animals per hectare. Animals gained 0.37 kg each per day at the lighter rate, but weeds encroached because of low grazing intensity. At the heavier rate the animals gained 0.28 kg but the sward was damaged by heavy trampling (Crowder, Chaverra & Lotero, 1970). In Panama, Rattray (1973) cited Ortega's recorded live-weight gain of 0.30 kg per day from unfertilized grass and 0.45 kg from grass fertilized with 90 kg each of phosphorus and nitrogen per hectare, but it was uneconomic. A stocking rate of two 205-kg animals per hectare was optimum for unfertilized grass.

Further reading

Tergas, Blue & Moore, 1971.