Cratylia argentea


Scientific name

Cratylia argentea (Desv.) Kuntze

Synonyms

Cratylia floribunda Benth.
Dioclea argentea Desv.

Family/tribe

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

Common names

        

Morphological description

Perennial, deep-rooting shrub reaching between 1.5 and 3 m in height.  When associated with taller plants it can show a somewhat voluble habit.  However, trees of up to 6 m have been found as well as completely prostrate plants.  Leaves are trifoliolate;  leaflets are broadly ovate with a silvery pubescence on their under surface.  Flowers are arranged in an elongated, many-noded pseudoraceme up to 30 cm long, with 6-9 flowers per node.  Size of flowers ranges from 1.5-3 cm (length and width);  petals are lilac or, very exceptionally, white.  Pods are straight, flat, up to 20 cm long and 1-2 cm broad, dehiscent, containing 4-8 oval to almost circular seeds of about 1.5 cm diameter.  Seeds are dark yellow to brown, when maturing under high-humidity conditions, dark brown.  Thousand seed weight is about 220 g, i.e. there are about 4,500 seeds/kg.

Distribution

Native to:
Basic passport data of collected germplasm accessions can be accessed on the internet (http://singer.cgiar.org/).  C. argentea is found exclusively in South America.  Its geographic distribution extends between 4ºS and 18ºS from northeast Brazil to central and west Brazil, and Bolivia and Peru east of the Andes (longitudinal range:  39ºW-77ºW).  Collection sites concentrate on the subhumid Cerrados region of Brazil.  In comparison with other Cratylia species, C. argentea is found in a wider range of habitats, with altitudes between 180 and 930 m asl, and main vegetation types ranging from Cerrados-Caatinga transition to Cerrados and seasonal forests;  soils are mostly well drained, sandy loams.

Uses/applications

On-station results with sheep have shown the value of C. argentea in supplementing a low protein diet and incrementing its voluntary intake, rumen digestibility, flow of nitrogen to the duodenum, total nitrogen and apparent nitrogen absorption.
Further information on the utilisation of C. argentea has been gathered in on-farm trials mainly in Central America.  C. argentea can be utilised both in mixed pastures with grasses and in fodder banks for in-situ grazing or for cut and carry for feeding as a dry season supplement as fresh forage or silage.
In addition to its value as dry season supplement, as silage or fresh, C. argentea is used as a protein supplement to replace feed concentrates for dairy cows, as hay and as a living hedge.

Ecology

Soil requirements

Soil pH 3.8-6.0.  Though apparently adapted also to higher pH soils, initial development of C. argentea in such soils is very slow.  Reasons are not yet well understood.  Needs well-drained soils.

Moisture

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From wet to dry tropics, annual rainfall 1,000-4,000 mm.  High drought tolerance, stays green in prolonged dry seasons (6-7 months).  Particularly well adapted to sub-humid zones, with a 5-6 month dry season.

Temperature

Warm season growth only, frost tolerance unknown.

Light

No information available.

Reproductive development

Seeds at the onset of the dry season.

Defoliation

C. argentea can be cut for the first time four months after planting;  it resists frequent cuts in intervals of 50-90 days even in the dry season, at a height of 30-90 cm above ground.  Plants cut at soil surface level have been observed to regrow extraordinarily well.  Plants have a high regrowth potential in the dry season;  30-40% of total dry matter yield occurs during the dry season as a result of high leaf retention.

Fire

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It has been observed to survive bush fires.

Agronomy

Establishment

C. argentea is established best by seed, through plant nurseries or - more commonly - direct seeding;  vegetative propagation trials with cuttings were not successful.  Seed does not require scarification and is superficially sown at less than 2 cm depth.  C. argentea nodulates readily with promiscuous cowpea rhizobia, though inoculation with Bradyrhizobium strains CIAT 2561 or 3564 is beneficial, in particular in acid soils with high aluminium saturation.  C. argentea is established at planting distances of 1-1.5 m between rows and 0.5-1 m between plants within the row.  Under glasshouse conditions it responded positively to calcium application of up to 1.5 t/ha lime in acid soils with high Al saturation.  This contrasts with observations of slow establishment at higher pH levels under field conditions;  hence further studies are needed for clarification.  Generally, initial growth is slow but can be positively influenced by fertilization and inoculation with rhizobia.

Fertiliser

No information available.

Compatibility (with other species)

In view of slow establishment, weed control during establishment phase is necessary.  The possibility to combine Cratylia with short duration crops or forages during the establishment phase is currently being evaluated.  Once established can be used in combination with pasture grasses such as Brachiaria spp.

Companion species

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Grasses:  Bunch grasses such as Panicum maximum and prostrate grasses such as Brachiaria spp.

Pests and diseases

Up to now (2004) no major diseases and pests have been reported.  In some sites, larvae of a beetle (Coleoptera: Melolonthidae) were observed to attack roots of C. argentea during establishment;  this can lead to the death of individual plants.

Ability to spread

No records, probably low.

Weed potential

Prolific seed producer.  However seed viability is short, hence weed potential is limited.

Feeding value

Nutritive value

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The nutritive value of C. argentea is among the highest reported for shrub legumes adapted to acid soils.  Crude protein ranges between 18% and 30% of DM, in vitro dry matter digestibility can reach 60-65%.   In contrast to many other tropical shrub legumes, C. argentea contains only traces of tannins.

Palatability/acceptability

Cattle readily consume it, though intake of immature Cratylia forage by sheep is low.

Toxicity

No toxicity recorded.

Production potential

Dry matter

Due to its slow initial growth, biomass production of C. argentea in the first year after establishment is low.  Based on production figures of 0.6-1 kg fresh material per plant in 60-90 days, the area needed for dry season supplementation can be calculated.
Dry matter production is high, with 8-week regrowth yields of 2-5 t/ha DM, both in the dry and wet periods.  On station, average yields of 50-150 g/plant DM for 8-week regrowth and 110-330 g/plant DM for 12-week regrowth have been recorded.

Animal production

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In trials with milking cows, a mix consisting of C. argentea and sugar cane for supplementation of pasture resulted in an increase of 1.2-2.2 litres milk/cow/day in response to C. argentea increments in the supplement mix.  Response to C. argentea was limited when cows of minor production potential were utilised or when the basal grass diet had CP levels above 7%.
Supplementation with Cratylia silage led to an increase in milk production of 0.5-1 L/day.

Genetics/breeding

Self fertile, but high level of outcrossing.

Seed production

Seed can be harvested from the establishment year onwards, though seed production in the first year is low.  C. argentea seems to be insect-pollinated which can result in outcrossing;  further studies are needed to define the level of outcrossing.  Seed formation is affected by cutting time and height as well as phosphorus fertilisation.  Positive results were found when C. argentea was cut back to 30 cm and fertilised with P at the beginning of the wet season.  Seed production extends from the start of the dry season over 2-3 months;  reported yields are 500-700 kg/ha/year.  Seeds show neither a marked physical (hard seedcoat) nor physiological dormancy but storage under cool and dry conditions is necessary to avoid loss of viability when keeping seed for several months before planting.

Herbicide effects

No information available.

Strengths

  • High drought tolerance due to a deep root system.
  • Adaptation to low fertility, acid soils.
  • For shrub legumes adapted to acid soils, C. argentea is one of the few higher-quality species.
  • Adapted to variable management and resists frequent cutting, even in dry periods.
  • Can be cut or grazed and fed fresh or as silage.
  • Persistence under frequent defoliation.
  • No serious pests or diseases.

Limitations

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  • Lack of adaptation to altitudes above 1,200 m asl.
  • Slow initial establishment.
  • Not tolerant of inundation.
  • Seed production not uniform.
  • Seed loses viability in storage if drying conditions are suboptimal.

Other comments

    

Selected references

Andersson, M.S., Peters, M., Franco, L.H. and Schultze-Kraft. R. Agronomic and morphological diversity in the Cratylia argentea world collection. Journal of Agricultural Science. In press.
Argel, P.J. and Lascano, C.E. (1998) Cratylia argentea (Desveaux) O. Kuntze: Una nueva leguminosa arbustiva para suelos ácidos en zonas subhúmedas tropicales. Pasturas Tropicales, 20, 37-43.
Argel, P.J., Lobo di Palma, M., Romero, F., González, J., Lascano, C.E., Kerridge, P.C. and Holmann, F. (2000) Silage of Cratylia argentea as dry-season feeding alternative in Costa Rica. In: Mannetje, L. 't (ed.). Silage making in the tropics with particular emphasis on smallholders. Proceedings of the FAO Electronic Conference on Tropical Silage, 1 September - 15 December 1999. FAO Plant Production and Protection Paper 161. pp. 65-67.
Pizarro, E.A. and Coradin, L. (eds) (1996) Potencial del género Cratylia como leguminosa forrajera. Memorias del taller sobre Cratylia realizado el 19 y 20 de julio de 1995, Brasilia, DF, Brasil. EMBRAPA-CENARGEN, CPAC and CIAT. Centro Internacional de Agricultura Tropical (CIAT), Cali, Colombia. Working Document No. 158.
Pizarro, E.A., Pereira da Silva, G., Schultze-Kraft, R. and Coradin, L. (1997) Áreas de ocurrencia y recolección de germoplasma de Cratylia argentea en los estados de Goiás, Mato Grosso, Minas Gerais y Tocantins en Brasil. Pasturas Tropicales, 19, 10-15.
Queiroz, L.P. de, Silva, M.M. da, Ramos, A.K.B. and Pizarro, E.A. (1997) Estudos reprodutivos em Cratylia argentea (Desv.) O. Kuntze and Cratylia mollis Mart. ex Benth. (Leguminosae-Papilionoideae). Pasturas Tropicales, 19, 20-23.
Raaflaub, M. and Lascano, C.E. (1995) The effect of wilting and drying on intake and acceptability by sheep of the shrub legume Cratylia argentea. Tropical Grasslands, 29, 97-101.
Schultze-Kraft, R. (1996) Leguminous forage shrubs for acid soils in the tropics. In: Elgersma, A., Struik, P.C. and Maesen, L.J.G. van der (eds) Grassland Science in Perspective. Wageningen Agricultural University Papers 96-4(1996). pp. 67-81.
Shelton, H.M. (2001) Advances in forage legumes: shrub legumes. In: Gomide, J.A., Soares Mattos, W.R. & Carneiro da Silva, S. (eds) Proceedings of the XIX International Grassland Congress, 11-21 February 2001, São Pedro, São Paulo, Brazil. pp. 549-556.
Wilson, Q.T. and Lascano, C.E. (1997) Cratylia argentea como suplemento de un heno de gramínea de baja calidad utilizado por ovinos. Pasturas Tropicales, 19, 2-8.

Internet links

Cultivars

Cultivars

Country/date released

Details

'Veraniega' Costa Rica (2001)     
'Veranera' Colombia (2002)     

Promising accessions

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Promising accessions

Country

Details

CIAT 18674, 22375, 22406, 22408 and 22409 Colombia Selected for high dry matter yields on acid soils