Desmodium dichotomum


Scientific name

Synonyms

Desmodium diffusum (Willd.) DC.
Hedysarum dichotomum Willd. [basionym]

Family/tribe

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

Common names

  

Morphological description

Herbaceous annual or perennial with branched angular stems which are moderately to densely pubescent with long tapering hairs.  Leaves trifoliolate with obliquely ovate-acuminate stipules that have lobes almost overlapping.  Leaflets ovate to elliptical, obtuse at the base and apex;  appressed pilose above and velutinous on the under surface, with long stout tapering hairs along the midrib and smaller hairs over the remainder, terminal leaflet 1.8–8 cm long and 2–6 cm wide, lateral leaflets 1.2–7 cm long and 1.0–4.8 cm wide.  Stipules are 5–10 mm long and 2–5 mm wide.  Inflorescences racemose with densely pubescent rachides, flowers pink or blue and small, with the standard being 3.3–3.5 mm long and 2.5–3 mm wide.  Fruit sessile to shortly stipitate, 4–6 articled, articles quadrate at maturity, nearly evenly indented on both sutures, 2–3 mm long and 2.5–3 mm wide, seed oval-reniform , 2 mm long and 1.5 mm wide.

Distribution

Native to:
Africa:  Cameroon, Chad, Ethiopia, Sudan, Uganda.
Asia:  China – Yunnan.
Indian Subcontinent:  India.
Indo-China:  Myanmar.
Malesia:  Indonesia – Celebes (south-west), Java (north-east).

Uses/applications

D. dichotomum has never been used commercially but has been trialled as an annual ley legume or as a forage crop on heavy clay soils in dry tropical and subtropical environments.  Although it has acted as an annual during this experimental work, it is usually described as a perennial .

Ecology

Soil requirements

The single accession of this species that has been used in experiments originated from the Sudan and is well adapted to heavy textured alkaline soils.

Moisture

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It is well adapted to dry and semi-arid environments on clay soils where it has the capacity to efficiently extract moisture from these soils.

Temperature

D. dichotomum has been productive in regions throughout the tropics of northern Queensland and the southern Queensland and northern New South Wales cropping systems which are environments with hot summers, with maximum temperatures frequently in excess of 35ºC.  It is burnt by frosts.

Light

No information available.

Reproductive development

No information available.

Defoliation

D. dichotomum is extremely palatable and will always be preferentially grazed.  Its high palatability can result in it being grazed to ground level so a large degree of grazing management is important if a seed crop is desired.

Fire

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No information available.

Agronomy

Establishment

D. dichotomum establishes readily in well prepared seedbeds.  It has a relatively small seed so the recommended depth of sowing is about 1 cm and should not exceed 2 cm.  The clay soils in which it might be used often have soil crusting characteristics which can reduce establishment significantly if seed is sown too deep and seed is of poor quality (low vigour).  D. dichotomum can have a large percentage of hard seed and this should be tested.  If hard seed is greater than 50%, then seed should be scarified before sowing.  The rhizobium requirements for D. dichotomum have not been evaluated but it could be expected that the standard strain for Desmodium (CB 627 in Australia) should be used.  Recommended planting rate when sown for a pure stand is 2 kg/ha.

Fertiliser

As in most legumes, D. dichotomum would be expected to respond to applications of P and Mo, and S may also be necessary in some situations.

Compatibility (with other species)

Most potential for D. dichotomum is as an annual ley legume or a forage crop.  Little is know of its compatibility but it should be compatible with most grass species in their first year of establishment.

Companion species

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No information available.

Pests and diseases

No pests and diseases have been observed in its early trials.

Ability to spread

It should have low ability to spread due to its very high palatability .

Weed potential

Unlikely to have weed potential because of its palatability .

Feeding value

Nutritive value

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No information available.

Palatability/acceptability

Extremely palatable and selectively grazed.

Toxicity

None reported.

Production potential

Dry matter

Dry matter yields in southern Queensland have ranged from 2–6 t/ha/year when grown under rainfed conditions of about 750 mm per annum on deep clay soils in a subtropical environment.

Animal production

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No information available.

Genetics/breeding

No detailed information but ease of seed production in glasshouse points to self pollination .

Seed production

Large scale seed production has not been attempted but seed is held on the plant for some time after maturity which is conducive to both hand and mechanised harvesting.

Herbicide effects

No information available.

Strengths

  • Adapted to alkaline clay soils.
  • High quality and potential as a ley legume and annual legume crop.
  • Extremely palatable.
  • Non bloating.

Limitations

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  • Small seed may result in establishment difficulties on clay soils.
  • Palatability may necessitate significant grazing management.

Other comments

  

Selected references

Clem, R.L. and Hall, T.J. (1994) Persistence and productivity of tropical pasture legumes on three cracking soils (Vertisols) in north-eastern Queensland. Australian Journal of Experimental Agriculture, 34, 161–171.

Internet links

  

Cultivars

Cultivars

Country/date released

Details

None released to date.      

Promising accessions

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Promising accessions

Country

Details

CPI 47186 Australia This single accession is the only one of this species that has been evaluated.  It is erect and has acted as an annual .