Trifolium rueppellianum


Scientific name

Synonyms

Trifolium subrotundum Steud. & Hochst. ex A. Rich.

Family/tribe

Family: Fabaceae (alt. Leguminosae) subfamily: Faboideae tribe: Trifolieae. Also placed in: Papilionaceae.

Common names

Rueppell's clover.

Morphological description

Annual up to 50 cm tall with glabrous or pilose stems, erect or decumbent.  Leaflets oblong or obovate, up to 24 x 18 mm, rounded to emarginate at the apex, glabrous or sparsely pilose, toothed margin.  Petiole up to 7 cm long, in upper leaves short or wholly united with stipules.  Stipules up to 15 mm long, united with petiole for two thirds of their length, with acuminate tips, entire.  Inflorescences globose, usually 15-30 flowered, about 17 mm across.  Pedicels up to 2 mm long.  Peduncle long, pilose near the top, bracts minute.  Calyx glabrous or pilose, usually 11-nerved;  lobes abruptly narrowed near the base, subulate for most of their length, 2-5 mm long and sometimes exceeding the corollaCorolla purple or rarely white, 5-8 mm long.  Pods 3-4 mm long and usually 2-3 seeded.  Seeds oval, brown and usually 1.5 x 1 mm.  This is a very variable species and several distinct ecotypes have been identified.

Distribution

Native to:
East Africa:  Cameroon, Democratic Republic of Congo, Equatorial Guinea, Ethiopia, Kenya, Rwanda, Sudan, Tanzania.
Found in upland grasslands and moors and as a weed in crop fields.

Other:
Widespread in tropical Africa.

Uses/applications

Regarded as good legume for grazing in native pastures with potential for use as an annual legume for pasture improvement.  Used for intercropping with wheat or barley in tropical highlands to improve soil nitrogen and quality of residues for livestock feed.  Clovers can also be used for hay and silage .  An excellent species for bee keeping and honey production.

Ecology

Soil requirements

Adapted to a wide range of soils from heavy clay vertisols and nitosols to loams and sandy loams from pH 4.0-8.0.  Tolerates seasonal waterlogging but prefers open grassland or cultivated areas.  It is not salt tolerant.

Moisture

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Adapted to high rainfall areas, although grows well in drier areas.  Rainfall in its natural range varies from 700-2,000 mm/yr.

Temperature

Adapted to the cool frost-free tropical highlands, T. rueppellianum occurs from 1,500-3,650 m in its native area.  Ground temperatures below 7ºC during the growing season retard growth and an elevation of about 2,600 m is about the upper limit for good forage production in tropical areas.

Light

Competition for sunlight leads to domination of stands by clovers that express rapid regrowth or tall stature.

Reproductive development

Flowering occurs at the end of the rains, from 60-100 days after planting in areas close to the equator with approximately 12-hour days.  Flowers are self fertile and high seeders.

Defoliation

Clovers tolerate moderate to high grazing.  Grazing late in the season reduces seed heads leading to reduced regeneration in following years.  They respond well to defoliation and compete better with grasses when mown to about 5-10 cm.

Fire

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No information available.

Agronomy

Establishment

Clovers are usually sown from seed at rates of 1-2 kg/ha.  Seeds are hard and require scarification before planting to ensure uniform germination.  Seeds are small and seedbeds should be well prepared to a fine, firm tilth.  Seeds are best sown just below the surface, lightly covered and rolled.  Germination occurs in about 5-7 days and young seedlings can be observed about 2 weeks after planting.  African Trifolium species are highly specialised in their rhizobium requirements.  In its native habitat it readily nodulates with native rhizobia, fixing the equivalent of 80-100 kg/ha N and nitrogen fertiliser is not required.

Fertiliser

Large dry matter yield increases are seen in response to P application on poorer soils.  Fertiliser (Di-ammonium phosphate DAP) is recommended when grown on poor soils at an optimum rate of 25-30 kg/ha P.  Application of 30 kg/ha P doubled the number of nodules and increased root weight by about 50%.

Compatibility (with other species)

T. rueppellianum combines well with other annual clovers and short-growing grasses.  It has been successfully used for intercropping with wheat without significant reduction of wheat grain and straw yields.

Companion species

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Pests and diseases

Under cool damp conditions, seedlings are sensitive to damping-off disease from the soil-borne fungi Pythium spp. resulting in rapid seedling death.  Roots susceptible to the nematode Meloidogyne incognita.  Plants are susceptible to red spider mites when grown in the greenhouse or shade areas.

Ability to spread

Plants dry and die back after seed set but hard seeds may be dispersed by water and small animals and remain in the soil for several years allowing pastures to regrow annually.  Substantial seed reserves were found in the top 5 cm of soil after 4 years of fallow in Ethiopia.

Weed potential

This species is very palatable and intensively grazed, reducing seed set and dispersal.

Feeding value

Nutritive value

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Crude protein levels vary with genotype, age at harvest and environment and range from 10-18% when plants are harvested after 120-135 days and can reach around 23% at the early flowering stage.  Lignin content is from 5-8% and IVDMD from 65-80%.

Palatability/acceptability

Palatability can be rather low when the plants are young, but improves as they reach maturity.

Toxicity

No information available.

Production potential

Dry matter

1,000 mm rainfall is needed for good forage production.  Yields are variable dependent on soil temperature, rainfall , fertility and genotype.  Peak yields are obtained about 120-130 days after sowing and usually decline as the plants age due to leaf drop.  Although moderate yields of 2-3 t/ha are common, yields can reach up to 5 t/ha with application of 40 kg/ha P.

Animal production

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No information available.

Genetics/breeding

2n = 16.  Plants are autogamous .

Seed production

At least 1,300 mm rainfall is needed for good flowering and seed production.  Plants flower at the end of the rains.  Seed yields of 200-300 kg/ha are common when harvested by direct heading, even though the pods shatter readily.  Yields of up to 750 kg/ha have been recorded for some genotypes with application of 40 kg/ha P.  Seeds are hard-seeded and store well.

Herbicide effects

No information available.

Strengths

  • Widely adapted to acid soils and low fertility in the tropical highlands.
  • Well adapted to waterlogged heavy clay vertisols.
  • Regenerates each year from seed stock in the soil.

Limitations

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  • Requires high rainfall for good herbage and seed production.
  • Cannot tolerate frost.
  • Tends to drop leaves and stems toughen with age.

Other comments

    

Selected references

Akundabweni, L. and Njuguna, S.K. (1996) Seed production of native hay clovers in the highlands of eastern Africa. Tropical Grasslands, 30, 257-261.
Dougall, H.W. (1962) The chemical composition of some species and varieties of Trifolium. East African Agricultural and Forestry Journal, 27 , 142-144.
Gillet, J.M. and Taylor, N.L. (2001) The World of Clovers . Iowa State University Press.
Kahurananga, J. and Asres Tsehay (1991) Variation in flowering time, dry matter and seed yield among annual Trifolium species, Ethiopia.  Tropical Grasslands, 25, 20-25.
Pritchard, A.J. and Mannetje, L. 't (1967) The breeding systems and some interspecific relations of a number of African Trifolium spp. Euphytica, 16, 324-329.
Wilson, G. P. M and Bowman, A. M. (1993) Trifolium species on the New South Wales north coast: 2. African species. Genetic Resources Communication No. 19.

Internet links

Cultivars

Cultivars

Country/date released

Details

None released to date.          

Promising accessions

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Promising accessions

Country

Details

ILRI 6260 Ethiopia Medium maturing ecotype with mean yield of over 7 t/ha.