Morphological description Tap-rooted, trailing perennial herb with slender stems, rooting at the nodes in some genotypes. Stems pilose with greyish hairs when young, glabrescent, lignified at base. Leaves trifoliolate; stipules triangular, petioles and petiolules pubescent; leaflets broadly to narrowly ovate, acute to acuminate at the apex, rounded or slightly wedge-shaped at the base; central leaflet larger and with longer petioles than the laterals, mostly 8-13 cm long, 3-8 cm wide, papyraceous to subcoriaceous, almost glabrous to pubescent on lower or both surfaces; frequently with a light-green marking along midrib. Inflorescence an axillary raceme with up to 30 flowers inserted in pairs along rachis; flowers papilionate, subtended by a pair of ovate-lanceolate-falcate bracteoles; calyx campanulate, 5-teethed with carinal tooth considerably longer than others; petals showy and cream-coloured with purple centre; standard orbicular-emarginate, 3-6 cm in diameter, pubescent outside; wings and keel much smaller than standard, directed upwards. Pod linear, compressed, up to 30 cm long, 1 cm wide, straight to slightly bent and beaked, subglabrous, containing up to 25 seeds, dehiscent. Seeds transversely oblong to rectangular, on average 5 mm x 3 mm, yellowish-brownish or black, plain, mottled or marbled. 15,000 - 25,000 seeds/kg.
Scientific name. Centrosema macrocarpum Benth.
Synonyms. Bradburya macrocarpa (Benth.) Kuntze Centrosema lisboae Ducke Centrosema magnificum Malme
Family/tribe Family: Fabaceae (alt. Leguminosae) subfamily: Faboideae tribe: Phaseoleae subtribe: Clitoriinae. Also placed in: Papilionaceae.
Common names. N.A.
Native to: Mesoamerica: Costa Rica, El Salvador, Honduras, Mexico, Nicaragua, Panama. South America: Bolivia, Brazil, Colombia, Ecuador, French Guiana, Guyana, Peru, Venezuela.
Uses/applications. Grazed pastures in mixture with grasses, as legume -only protein banks, cut-and-carry, and soil cover in orchards and plantations.
Soil requirements. Adapted to low- to medium-fertility, well drained soils of various textures, particularly loams. Tolerates very acid conditions, with high soluble Al and Mn.
Moisture. Humid to sub-humid climate with annual rainfall >1,000 mm, 3-6 dry months. Once established, C. macrocarpum is very drought tolerant.
Temperature. It occurs naturally from 22ºN in Mexico to 18ºS in Bolivia, and from near sea level over much of the latitudinal range to 1,650 m asl in Colombia. Average annual temperatures at collection sites are mostly in the range 24-26ºC, and down to 22ºC. Warm season growth only.
Light. Moderately shade tolerant.
Reproductive development. Very photoperiod-sensitive: flowering triggered by short days even close to the equator, and stimulated by removal of accumulated biomass. Tripping of flowers by large insects required for pod set.
Defoliation. It is tolerant of grazing and cutting once well established, but in mixtures with grasses, it tends to decline under intensive grazing.
Fire. Well-established plants recover after fire.
Guidelines for the establishment and management of sown pastures.
Establishment. Seed should be inoculated with CIAT 3101 (= CB 3125 in Australia) strain rhizobium< /A> prior to planting. A sowing rate of 3-5 kg/ha of scarified seed is usually adequate.
Fertiliser. Responds well to fertilisation on low fertility soils, mainly P and K.
Compatibility (with other species). Combines well with bunch grasses and other species that produce a more open stand.
Grasses: Andropogon gayanus , Brachiaria brizantha , B. humidicola , Panicum maximum .
Legumes: Stylosanthes capitata , S. guianensis.
Pests and diseases. Not seriously affected by the major Centrosema diseases, Rhizoctonia foliar blight, anthracnose, Cercospora leaf-spot and bacterial wilt. Soybean mosaic virus infection by aphids has been reported. Insects may eat leaves, especially during dry periods.
Ability to spread. Spread is localised by stolon development, extensive spread being limited by low amounts of seed produced under grazing.
Weed potential. None.
Nutritive value. In young foliage: CP 20-30%, IVDMD 45-70%, P about 0.20%.
Palatability/acceptability. Very palatable.
Toxicity. None reported.
Dry matter. On low-fertility soils: Animal production. In association with Andropogon gayanus , 170-200 kg/yr/steer LWG (400-600 kg/ha) possible. In association with Andropogon gayanus or Brachiaria humidicola , milk yields of Holstein cows 15-20% higher than on grass alone.
Genetics/breeding. 2n = 22; self-fertile, but considerable outcrossing because of dependence on tripping by insects.
Seed production. Handpicked seed yields of 50-500 kg/ha have been obtained from a potential yield of 800 kg/ha.
Herbicide effects. Tolerant of alachlor, metolachlor and pendimethalin, but not oxyfluorfen, pre-emergent herbicides; and of bentazone and fluazifop-butyl, but not 2,4-D amine and dalapon as post-emergent applications.
- Adaptation to very acid, low-fertility soils.
- Good drought tolerance. High nutritive value.
- Tolerant of main Centrosema diseases.
- Selectively grazed.
- Lack of persistence in mixture with grasses.
- Low seed production without proper managerial skills.
- Keller-Grein, G., Amézquita, M.C., Lema, G. and Franco, L.H. (1993) Multilocational testing of grasses and legumes in the humid tropics of South America. Proceedings, XVII International Grassland Congress, 8-21 February 1993, New Zealand and Australia. pp. 217-219.
- Lascano, C.E. and Avila, P. (1991) Potencial de producciÓn de leche en pastures solas y asociadas con leguminosas adaptadas a suelos ácidos. Pasturas Tropicales, 13, 2-10.
- Pérez, J.M., Szott, L.T. and Arévalo, L.A. (1993) Pijuayo con cobertura de leguminosas. In: Mora Urpí, J., Szott, L.T., Murillo, M. and Patiño, V.M. (eds) Memorias del IV Congreso Internacional sobre Biología, Agronomía e IndustrializaciÓn del Pijuayo, Iquitos, Perú, 1989. Editorial de la Universidad de Costa Rica, San José, Costa Rica. pp. 309-322.
- PinzÓn, B., Argel, P.J. and Montenegro, R. (1989) Selectividad de herbicidas y control de malezas en Centrosema macrocarpum . Pasturas Tropicales, 11, 7-12.
- Schultze-Kraft, R. and Clements, R.J. (1990) (eds) Centrosema : Biology, Agronomy , and Utilization. Centro Internacional de Agricultura Tropical (CIAT), Cali, Colombia.
- Schultze-Kraft, R. (1992) Centrosema macrocarpum Benth. In: 't Mannetje, L. and Jones, R.M. (eds) Plant Resources of South-East Asia No. 4. Forages. pp. 82-84. (Pudoc Scientific Publishers, Wageningen, the Netherlands).