Stylo
Stylosanthes guianensis

Summary


Common Name

According to ‘t Mannetje, Stylosanthes guianensis common name is Stylo, Brazilian lucerne, and tropical lucerne.

Scientific Name

The scientific name is Stylosanthes guianensis (Aublet) Swartz (‘t Mannetje).

Cultivars

Stylo cultivars released from Australia include (Bogdan, ‘t Mannetje):

Seed Description

Seeds are about 2.2 mm long and 1.5 mm wide, mostly pale brown but also vary from yellow to almost black (Bogdan).

Seedling Description

No information is available in this database on this topic.

Mature Plant Description

Stylo is a multi-branched erect or suberect (under grazing) herbaceous perennial legume, 30-120 cm (12-48 inches) high. Its leaves are trifoliate, with leaflets 0.5-4 cm long and 0.2-1.5 cm wide. The flowering heads are 1-4 cm long with 2-40 yellow, orange-yellow or red streaked flowers, 4-8 mm long (Bogdan). Stems are hairy and become woody at the base with age (FAO).

Temperature

Stylo is primarily adapted to the hot humid tropics, however several cultivars have been released that will grow in the subtropics as well. Bogdan reports that it can survive frosts.

Origin and Geographic Distribution

Stylo is considered to be indigenous to Brazil and is naturally distributed in Paraguay, Bolivia, Peru, Colombia, Venezuela, Guyana and Central America. It has now been introduced all over the tropical world and is considered to be naturalized in most tropical countries (‘t Mannetje). It can also be found to a lesser extent in the subtropics (Bogdan).

Ecology

Stylo occurs naturally in hot, tropical climates. It is particularly well adapted to poor acid soils with high Al and Mn content. It is a short-day plant with a critical photoperiod between 12-14 hours, varying on the cultivar (‘t Mannetje). A prolific seed producer, over 70% of stylo seeds can be hardseeded and seeds may be viable up to 3 years in the soil (Bogdan).

Water

Stylo can grow under a wide range of rainfall, from 600-700 mm (about 25 inches) up to 2,500 mm (about 100 inches). In pot trials, it was tolerant to flooding. It can survive long dry periods (Bogdan).

Nutrients

Stylo responds well to improved soil fertility, particularly P, but can grow on infertile soil (partly due to endotrophic mycorrhiza found in roots). Fertilizer P is recommended at early stages of plant growth (50, 100 or 150 kg/ha superphosphate, about 45-90 or 134 lb/acre). Positive responses to sulfur, copper, potassium and calcium have also been reported.

Soil pH

Stylo grows at a pH between 4.0 – 8.3 (NRCS Tech Guide).

Soil Type

Stylo will grow on all soils types but is best adapted to poor acid soils with high Al and Mn contents (‘t Mannetje). The FAO reports that stylo does well on coarser textured soils and less well on heavy clays, preferring well-drained open textured soils.

Shade Tolerance

Stylo is not considered shade tolerant (Bogdan). NRCS describes stylo as having fair shade tolerance.

Salinity Tolerance

Stylo is not considered very salt tolerant (FAO).

Herbicide Sensitivity

Bogdan reports that 2,4-D at establishment or 2,4,5-T a month before sowing will not harm seedlings. The FAO reports that 2,4,5-T will cause a 50-75% reduction in stylo 12-18 months after spraying (1.1 kg/ha acid equivalent, mixed with water).

Life Cycle

Stylo plants have a juvenile phase during which floral initiation does not take place. It is a prolific seed producer, but more than 70% may be hardseeded. Hardseedness breaks down naturally under hot conditions (‘t Mannetje). The seeds can remain in the soil undamaged for a long time, and seedling emergence can occur up to 3 years after the crop has been plowed in (Bogdan).

Seeding Rate

2-6 kg/ha (‘t Mannetje)., about 2-5 lb/ac.

Seeding Depth

No information is available in this database on this topic.

Seeding Method

Stylo is hardseeded and must be pretreated to improve germination by hot water treatment (10 minutes at 80° C) (‘t Mannetje), mechanical scarification, sulfuric acid treatment or freezing (-17° C for 7 days) (Bogdan) increases germination rates. Seeds can be drilled in rows or can be oversown directly into natural grassland without any soil tillage. It can also be established vegetatively from cuttings, but establishment is slow and expensive. (Bogdan)

Seeding Dates

Year round in Hawai`i.

Inoculation

NRCS recommends using a stylo specific inoculum (NRCS). Inoculation is not always necessary for stylo. Certain cultivars can be effectively inoculated by cowpea Rhizobium (‘Schofield’). ‘Oxley’ and several of the Brazilian cultivars require a special inoculant. Nodules are small and begin to appear at 3 weeks after germination. Nodulation varies with soil pH with highest N fixation occurring at pH 6.0 (Bogdan).

Seed Cost

No information is available in this database on this topic.

Seed Availability

Readily available.

Days to Flowering

No information is available in this database on this topic. Flowering heads do not all emerge simultaneously and flowers do not all flower at the same time (Bogdan).

Days to Maturity

No information is available in this database on this topic.

Seed Production

Seed production is difficult because mature seed can shed while some flowers are only beginning to open. Also there is a glutinous secretion on the flower heads which makes harvesting difficult. Equipment has been developed in Australia to harvest seed mechanically (Bogdan).

Seed Storage

No information is available in this database on this topic.

Growth Habit

Stylo is an erect herbaceous perennial with branching upright stems up to 1 meter tall (39 in.), which may become more prostrate under grazing (FAO).

Maximum Height

Stylo can grow to a maximum height of 120 cm (47 in.) high (Bogdan).

Root System

Stylo has a strong taproot and small round root nodules (‘t Mannetje).

Establishment

Stylo can also be established vegetatively from cuttings, but establishment is slow and expensive (Bogdan).

Maintenance

No information is available in this database on this topic

Mowing

When mown, woody stems should not be cut too low or regrowth will be adversely affected (‘t Mannetje). Mowing encourages the growth of stylo. Cutting below 15 cm (about 6 in.) is not recommended. Herbage can be cut at 6 to 16 week intervals (Bogdan).

Incorporation

Not applicable. Not generally used as a green manure.

Harvesting

Stylo is usually harvested by grazing animals or mown for stall feeding or artificial drying. It is usually consumed fresh since hay making and ensiling are not commonly practiced in the humid tropics (‘t Mannetje).

Equipment

No information is available in this database on this topic.

Uses

Mixtures

Pure stands of stylo are used mainly for seed production. Some grasses that have been grown successfully with Stylo are: Digitaria decumbens, D. smutsii, Chloris gayana, Cenchrus ciliaris, Melinis minutiflora, Setaria anceps, Andropogon gayanas, Heteropogon contortus, Hyparrhenia rufa, Panicum maximum, Pennisetum polystachion and P. Purpureum (Bogdan).

Biomass

No information is available in this database on this topic.

N Contribution

Estimates vary with the highest reported at 240 kg/N/ha (Bogdan), or 214 lb/N/ac.

Non-N Nutrient Contribution

No information is available in this database on this topic.

Effects on Water

No information is available in this database on this topic.

Effects on Soil

Bogdan reports adverse effect on cotton crops grown after stylo possibly due to root exudates.

Effects on Livestock

Animal production on Stylo is acceptable: crude protein is about 12-18% (Bogdan). Palatability is not very high although stylo is readily eaten by sheep and cattle. Stylo grown on low P soil will be phosphorous deficient; animal diets should be supplemented (‘t Mannetje).

Pest Effects, Insects

No information is available in this database on this topic.

Pest Effects, Nematodes

No information is available in this database on this topic.

Pest Effects, Diseases

Stylo is susceptible to anthracnose disease caused by the fungi Colletotrichum gloeosporioides and C. dematium and symptoms include black lesions on the leaves and stems with eventual plant death. Disease resistant cultivars exist (‘t Mannetje).

Pest Effects, Weeds

No information is available in this database on this topic.

Pest Effects, Vertebrates

No information is available in this database on this topic.


Uses in the Pacific Region

Uses in Hawai`i

The Hawai`i Natural Resources Conservation Service Technical Guide includes Stylo (cv. ‘Cook’ ‘Endeavour’ ‘Oxley’ ‘Schofield’). Their specification describes Stylo as follows:


References

Bogdan, A.V. 1977. Tropical Pasture and Fodder Plants. Longman Inc., New York. pp. 397-402.

‘t Mannetje, L., 1992. Stylosanthes guianensis (Aublet) Swartz. In: ’t Mannetje, L. & Jones, R.M. (Editors): Plant Resources of South-East Asia No 4. Forages. Pudoc-DLO, Wageningen, the Netherlands. pp. 211-213.

Evans, Dale O., Joy, Robert J., & Chia, C.L., 1988. Cover Crops for Orchards in Hawaii. Hawaii Institute of Tropical Agriculture and Human Resources, University of Hawaii at Manoa, Honolulu, Hawaii, United Stated. 16pp.

FAO Web Site:

USDA Natural Resources Conservation Service, Hawai`i Field Office Technical Guide, Section IV, Code 340 "Cover and Green Manure Crop" May 1992. Pacific Islands Area Field Office Technical Guide (eFOTG) - East Area

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These webpages were originally generated under a grant program from Western SARE entitled "Covering New Ground: Tropical Cover Crops for Improving Soil Quality" EW98-012 (1998-2002).