Stylo
Stylosanthes guianensis
Summary
- Tropical herbaceous perennial legume
- Has a low phosphorus requirement
- Used primarily as a pasture legume for humid tropical regions
- Used as a cover crop in plantations, as a green manure crop, and as a fallow crop
- Recommended in Hawai`i for orchard crops
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):
- ‘Schofield’: adapted to hot humid tropical climates (FAO reports that this cultivar collapsed with anthracnose in 1978)
- ‘Oxley’: tolerates subtropical conditions, lower temperatures, rainfall of 650-900 mm (26-35 inches) and more resistant to heavy grazing
- ‘Cook’: tropical, fast growing, high yielding
- ‘Endeavour’: noted for vigorous initial growth and adapted to high rainfall coastal Queensland.
- Brazilian cultivars include ‘Deodoro’, ‘Deodoro 2’, and ‘IRI-1022.’
- The Peruvian release ‘Pucallpa’ is specifically for the humid tropics and low pH soils. It is used in tropical China as ‘Pi Hua Dou 184.’ (‘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
- Used primarily as a pasture legume for humid tropical regions
- Used as a cover crop in plantations, as a green manure crop, and as a fallow crop
- Recommended in Hawai`i for orchard crops
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
- Small plots in western Samoa reported herbage yields of stylo over 15 tons dry matter/ha.
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:
- Good heat tolerance
- Tolerates acid/low fertility soils;
- Minimum seeding rate of 25 lbs. pure live seed/acre;
- pH range from 4.0-8.3;
- Inoculant group: stylo specific;
- Medium maintenance required;
- Fair shade tolerance;
- Fair drought tolerance;
- Rainfall range of 50+ inches;
- Medium rate of establishment;
- Elevation range from 0-3000 ft.
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