Aeschynomene falcata (Poir.) DC.

Hedysarum falcatum Poir.

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

jointvetch (Australia).

A prostrate, herbaceous perennial with a strong taproot.  Stems pubescent (sometimes hispidulous), to 1 m long and 1-3 mm diameter.  Leaves 5-7 (-9) foliolate, leaflets obovate to elliptical about 6-12mm long, 2.5-4 mm wide, pubescent on both surfaces.  Inflorescence comprising 1 or 2 yellow flowers with standard 7-9 mm long.  Pod curved, 15-30 mm long comprising 4-8 articles, dehiscing along the scalloped suture at maturity.  Seeds 2 mm long, 1.5 mm wide, commonly dark brown, but varying from light yellowish-brown to almost black;  c. 370,000-450,000 seeds/kg.
Plants morphologically similar to A. elegans and A. brevifolia.

Native to:
South America:  Argentina (east Chaco, Corrientes, Misiones), Bolivia, Brazil, Colombia, Paraguay.

Naturalised in:
Locally in subtropical eastern Australia.

Sown as a permanent component of low input pastures (e.g. Axonopus, Imperata, Heteropogon).

Free draining sandy to light clay soils of low to moderate fertility and acid to neutral pH.

Originates from areas with rainfall to about 1,800 mm.  Usually recommended for sowing between about 900 and 1,500 mm average annual rainfall.  Persists down to about 700 mm AAR, but usually less productive.  Very drought hardy, and continues to grow during the dry season.  Prefers good drainage, although will tolerate temporary waterlogging.

Native to subtropics and upland tropics, from about 7ºN in Colombia to 28ºS in Argentina, and from <100 m asl in the subtropics to 2,000 m asl in the tropics.  This equates to an annual average temperature range of about 19-22ºC.  Tops are burnt by frost but plants recover with onset of warm conditions.  Early season growth varies with ecotype.

Full sunlight to moderate shade.

Flowers and sets seed throughout the growing season.

Under heavy grazing, the plant adopts a low rosette growth habit, but still produces sufficient seed to allow spread and long-term persistence.

Recovers well from annual burning of pastures, fire stimulating hard seed breakdown and potential recruitment.

Guidelines for the establishment and management of sown pastures.

Has a high level of hard seed, which is usually scarified in the harvesting and threshing process.  Establishes into burnt native pasture or after soil disturbance, although if seed is expensive, a good seedbed is preferable.
Somewhat promiscuous, but nodulates most effectively with CB 2312 or common cowpea type rhizobia.

Persists on infertile soils but responds to low inputs of phosphorus if levels are low (say 5-10 ppm available P).  May require additional Mo on some acid soils.

Combines with low growing dense pastures and more open erect grasses in low fertility situations.  Favoured by heavy grazing.

Grasses:  Axonopus fissifolius , Cynodon dactylon , Digitaria didactyla , Heteropogon contortus , Paspalum dilatatum , P. notatum .
Legumes:  Stylosanthes guianensis var. intermedia, Lotononis bainesii , Chamaecrista rotundifolia .

Possesses a high degree of resistance to Amnemus weevil (Amnemus quadrituberculatus) and is resistant to root knot nematodes (Meloidogyne spp.).  Can be attacked by anthracnose (Colletotrichum  sp.) during extended wet weather.  Seedlings are susceptible to damping off caused by fungi such as Rhizoctonia sp. and Pythium sp.

Seed is eaten and spread by cattle into new pastures.  In larger areas with an environment well suited to A. falcata, seedlings can appear in significant numbers considerable distances from the source stand of seed.

Low - spreads easily, but not aggressive.

Good, but low proportion of total pasture.  1.5-3% N, 0.1-0.2% P, 42-65% IVDMD.

Very palatable and grazed selectively by cattle, sheep and marsupials.

No record.

Yields generally low, around 1-2 t/ha DM, up to 5 t/ha DM under good conditions.

Augments low quality grass pastures.

Self-pollinating;  2n = 20.

Flowering continues for most of the growing season, declining with the onset of cool conditions.  Gives better seed production when supported by a framework of erect (but fine-stemmed) grass.  Can be harvested with direct heading and suction harvesting.  About 60 kg seed/crop, possibility of 2 crops/yr.  Up to 680 kg/ha from small plots.  Anthracnose in the growing tips and pod shattering reduce yields.

Susceptible to acifluorfen, 2,4-DB and 2,4-D, and tolerant of bentazone, fluazifop-butyl and sethoxydim.

• Persistent and spreads naturally.
• Palatable.
• Grows on poor soils.

• Little commercial seed.
• Susceptible to anthracnose.
• Low herbage yield.

Bielig, L.M. (1997) Chromosome numbers in the forage legume genus, Aeschynomene L. Sabrao Journal, 29, 33-39.

Cook, B.G. (1992) Aeschynomene falcata (Poiret) DC. In: 't Mannetje, L. and Jones, R.M. (eds) Plant Resources of South-East Asia No. 4. Forages. pp. 39-40. (Pudoc Scientific Publishers, Wageningen, the Netherlands).

Jones, R.M., McDonald, C.K., Clements, R.J. and Bunch, G.A. (2000) Sown pastures in subcoastal south-eastern Queensland: pasture composition, legume persistence and cattle liveweight gain over 10 years. Tropical Grasslands, 34, 21-37.

Rudd, V.E. (1955) The American species of Aeschynomene. Contributions from the United States National Herbarium, 32, 88-90.

Wilson, G.P.M. (1980) Bargoo jointvetch: tough legume for tough country.  Agricultural Gazette of New South Wales, 91, 51-53.

http://www.pi.csiro.au/ahpc/legumes/pdf/bargoo.pdf
http://www.fao.org/ag/AGP/AGPC/doc/Gbase/DATA/pf000002.htm

Cultivars	Country/date released	Details
'Bargoo' (CPI 11500)	Australia (1973)	From Cordillera, Paraguay (c. 25.5ºS, 200 m asl, rainfall 1,500 mm).  Selected for low fertility, beef pastures in sub-tropics.  Since proven well adapted to less fertile, well-drained soils from about 21-30ºS.

Promising accessions	Country	Details
ATF 2194	Australia	From Concepcion, Paraguay (23.47ºS, 70 m asl, rainfall 1,350 mm).  Similar adaptation to that of 'Bargoo'.  Better growth (particularly early season), less shattering, less anthracnose than 'Bargoo'.