Stylosanthes fruticosa


Scientific name

Stylosanthes fruticosa (Retz.) Alston

Synonyms

Stylosanthes mucronata Wild.
Arachis fruticosa Retz. [basionym]

Family/tribe

Family: Fabaceae (alt. Leguminosae) subfamily: Faboideae tribe: Aeschynomeneae subtribe: Stylosanthinae. Also placed in: Papilionaceae.

Common names

African stylo.

Morphological description

Woody perennial herb, 0.1-1 m tall, usually with a thick woody rootstock and many branches.  Stems pubescent to densely hairy.  Leaflets elliptic or lanceolate, narrowed to both ends, 5-33 mm long, 1-9 mm wide, usually pubescent and bristly.  Receptacle 5-7 mm long;  calyx-lobes 2.5-3 mm long.  Flowers cream to yellow, borne in dense oblong terminal heads.  Standard 5-7 mm long,  4-5 mm wide.  Pod 4-9 mm long with 2 segments 3.5-4 mm long, 2-2.5 mm wide and curved beak 1-3 mm long, usually densely pubescent with single seed of 1.5-2 mm.

Distribution

Native to:
Tropical Africa:  Angola, Botswana, Burkina Faso, Burundi, Cameroon, Chad, Cote D'Ivoire, Ethiopia, Gambia, Ghana, Guinea-Bissau, Kenya, Malawi, Mali, Mozambique, Namibia, Niger, Nigeria, Rwanda, Senegal, Somalia, South Africa, Sudan, Swaziland, Tanzania, Togo, Uganda, Zaire, Zambia, Zimbabwe.
Asia:  Arabia, Madagascar, India, Sri Lanka.
Found in grassland, woodland, scrub and weed of old cultivations.

Uses/applications

Used in pasture in mixtures with perennial grasses or for improving fertility of fallow areas through leaf drop and nitrogen fixation.  Prostrate forms are useful for soil erosion control.  It has also been intercropped with millet in dry areas.  It is heavily grazed by livestock in native pastures in Africa.

Ecology

Soil requirements

While growing well on sandy well-drained alkaline soils, it is tolerant of acid and clay soils.  It grows well in soils from pH 4.0-8.0 and is tolerant of low phosphorous.

Moisture

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Rainfall in its natural range varies from 350-1,500 mm/year.  The species is moderately tolerant to waterlogging and very drought tolerant and has been successfully cultivated in areas of less than 300 mm rainfall.  It can behave as an annual species in areas with very poor rainfall .

Temperature

Occurs from sea level up to about 2,000 m in the tropics.  It has no tolerance to heavy frost, although it can tolerate short cool periods and light frosts better than some other Stylosanthes species.

Light

Can tolerate light shade and frequently grows under Acacia in the African savannas.

Reproductive development

Plants are day neutral, usually flowering in less than 60 days in the tropics. Temperature is critical for flowering with peak flowering occurring in daytime temperatures from 25-30ºC.  High temperatures above 30ºC can inhibit flowering.

Defoliation

Although it can withstand moderate grazing, this species is not tolerant of heavy grazing.

Fire

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Although not tolerant to fire, plants establish rapidly after fire from the hard seeds remaining in the soil if there is sufficient moisture.

Agronomy

Establishment

Establishment of S. fruticosa is similar to that for other Stylosanthes species.  Establishment is by seed at rates of 3-6 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 2-5 days and young seedlings emerge about 1 week after planting.  It can also be oversown into pastures by broadcasting, followed by a light harrowing.  S. fruticosa is not reported to have specific rhizobium requirements and in its native habitat it readily nodulates with native rhizobia.

Fertiliser

No information available.

Compatibility (with other species)

Compatible with perennial grasses that are protected from heavy grazing, including Andropogon gayanus , Heteropogon contortus and Hyparrhenia hirta.  Can be inter-cropped with millet in the Sahel.

Companion species

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Pests and diseases

Although reported susceptible to anthracnose in Queensland, Australia, several tolerant accessions have been observed in trials in Africa.

Ability to spread

Hard seeds may be dispersed by water and small animals and remain in the soil for several years allowing pastures to regrow annually.

Weed potential

Low weed potential due to high palatability and low tolerance to heavy grazing.

Feeding value

Nutritive value

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Although the nutritive value is not as high as other more leafy legumes, crude protein levels are at least 8% of dry matter and can reach 10% with application of 300 kg/ha of superphosphate.

Palatability/acceptability

Much sought after by livestock and heavily grazed.

Toxicity

No information available.

Production potential

Dry matter

Dry matter production from small plots was 6,000 kg/ha, while lower yields of up to 3,000 kg/ha were more commonly obtained in the Sahel.

Animal production

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S. fruticosa is reported to have a dry matter digestibility of 66% and high dry matter intake of 71 g, indicating the species could have reasonable potential for livestock production.

Genetics/breeding

2n = 40.  This species is an allotetraploid closely related to S. scabra and has been classified with it on morphological grounds, although recent genetic studies using RAPDs, RFLPs and chloroplast DNA suggests that they are in fact distinct taxa.  It is also related to the other African species S. erecta and it is reported that it possibly hybridises naturally with it where the two species overlap, leading to hybrid populations with broad variation.

Seed production

Plants start to flower after only 2 months, towards the end of the rains, and mature seeds are ready for harvest about 4-5 months after planting.  This species is reported as a heavy seeder, although due to the small seed size it only produces about 15-20 kg/ha seeds.  The pods are firmly held by bracts and seeds are best harvested by cutting the entire plant when the majority of pods are mature, drying and beating so that the pods fall.  The seeds are extracted from the pods by a belt thresher or hand rubbing.  Seeds are hard-seeded and store well.

Herbicide effects

No information available.

Strengths

Limitations

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  • Cannot withstand heavy grazing.
  • Relatively low productivity compared to other species of Stylosanthes.
  • Affected by anthracnose.

Other comments

  

Selected references

Hakiza, J.J., Lazier J.R. and Sayers, A.R. (1987) Characterization and evaluation of forage legumes in Ethiopia: preliminary examination of variation between accessions of Stylosanthes fruticosa (Retz.) Alston. In: Dzowela, B.H. (ed.) African forage plant genetic resources, evaluation of forage germplasm and extensive livestock production systems. Proceedings of the third PANESA workshop held at Arusha, Tanzania, 27-30 April 1987. Pasture Network for Eastern and Southern Africa. pp. 174-191.
Kouame C.N., Powell, J.M., Renard, C.A. and Quesenberry, K.H. (1993)  Plant yields and fodder quality related characteristics of millet-stylo intercropping systems in the Sahel. Agronomy Journal, 85, 601-605.
Liu, C.J., Musial, J.M. and Thomas, B.D. (1999) Genetic relationships among Stylosanthes species revealed by RFLP and STS analyses. Theor.Appl.Genet., 99, 1179-1186.
Stace, H.M. and Edye, L.A. (eds) (1984) The biology and agronomy of Stylosanthes . Academic Press, Sydney, Australia.
Vander Stappen, J. and Volckaert, G. (1999)  Molecular characterization and classification of Stylosanthes mexicana, S. macrocarpa, S. seabrana and S. fruticosa by DNA sequence analysis of two chloroplast regions.  DNA Seq., 10, 199-202.

Internet links

Cultivars

Cultivars

Country/date released

Details

None released to date.      

Promising accessions

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Promising accessions

Country

Details

ILRI 13860 Sadore, Niger Tall ecotype collected from Niger, high yielding.