Desmodium heterocarpon subsp. ovalifolium


Scientific name

Desmodium heterocarpon (L.) DC subsp. ovalifolium (Prain) H. Ohashi

Synonyms

Desmodium ovalifolium (Prain) Wall. ex Merr., nom.illeg.
Desmodium polycarpon (Poir.) DC. var. ovalifolium Prain

Family/tribe

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

Common names

desmodium, ovalifolium (English);  desmodio (Spanish);  khonthi din (Thailand);  trang qu'a xoan (Vietnam).

Morphological description

An aggressively creeping, stoloniferous legume that may reach 1 m height in dense stands.
Stems are multi-branched but quite woody at their base.  Young plants always have single broadly elliptical leaves;  on more mature plants leaves may be unifoliate or trifoliate, with terminal leaflet larger than laterals.  Terminal leaflets 30-45 mm by 15-30 mm without any markings, glabrous and glossy on upper surface, pilose underneath.  Inflorescence is a densely flowered raceme 2-5 cm long, with purple to dark pink flowers, turning bluish with age.  Pods comprised of 2-8 segments, 3 mm long, covered in dense hairs;  held in a dense, erect cluster;  dehiscent when ripe.  Mature seeds yellow.

Distribution

Native to:
Tropical southeast Asia.  Widely distributed from mainland China to India and Sri Lanka through Myanmar, Thailand, Malaysia, Philippines, Indonesia and the Pacific Islands.  Ovalifolium is generally a lowland species of high rainfall environments.

Accessions marketed in Singapore have been spread to most tropical countries.

Uses/applications

Mainly used in southeast Asia as a cover crop for erosion and weed control in tropical tree plantations (including rubber, oil palm, coffee, tea), with potential use as a green manure.  Incorporated in grass/legume pastures in South America.  Possible use in agro-forestry due to its shade tolerance and comparatively shallow rooting.  Can be used for cut-and-carry and restoration of degraded soils.

Ecology

Soil requirements

Extremely well adapted to low fertility, acid soils (pH 4-7), with high Al and Mn, and low P.
64% of maximum yield is obtained at a soil Al saturation of 89% and P content of <2 ppm.  When subjected to 86 ppm soil Mn, DM yield was higher than at 10 ppm , indicating excellent adaptation to acid soils.

Moisture

Top

Humid and moist sub-humid tropical lowlands with 1,200-4,500 mm rainfall, preferably >2,000 mm and weak dry season of no more than 3-4 months.  Good tolerance of waterlogging and periodic flooding.  Dry conditions can cause leaf drop and reduced flowering.  Has performed well on seasonally flooded savannas in Colombia and on poorly drained humic gleys in the Brazilian savannas, but CIAT 350 reported to have yield reduction of 70% under intermittent flooding.

Temperature

Warm season growth only, being native to the lowland humid-tropics and showing poor adaptation for growth beyond these environments.

Light

One of the most shade tolerant leguminous cover/forage crops.  Grows well under the heavy shade of rubber and oil palm plantations.

Reproductive development

No information available.

Defoliation

Good tolerance to grazing or cutting.  Stocking rates should be kept high (3-4 animals/ha) to maintain nutritional value and grass component.

Fire

Top

Sensitive to burning, but fires are rare in its environmental adaptation range.

Agronomy

Establishment

Easy to establish from seed without full seedbed preparation, and can be established from stolons.  However, germination and establishment from seed are slow, so weed control necessary at this stage.  In pasture mixes, sow at 0.5 kg/ha.  As a cover crop under plantation crops, sow at 1-2 kg/ha, although rates of up to 5 kg/ha have been used.  Seed should be scarified and preferably inoculated.  Seed can also be spread though the dung of grazing animals.  Seed can be difficult to obtain and rooted stems can be planted vegetatively.

Fertiliser

On very acid infertile soils, the species responds to lime, phosphorus, magnesium, sulphur and boron fertilisation.

Compatibility (with other species)

Forms productive, persistent pastures with aggressive, stoloniferous , turf forming grasses such as Brachiaria humidicola and B. decumbens .  Can become dominant in pastures unless they are grazed heavily.

Companion species

Top

Grasses:  Brachiaria decumbens , B. brizantha B. humidicola , Digitaria eriantha .  In the Colombian savannas, combined well with Andropogon gayanus and Panicum maximum .  The species is also reported to grow well with Cynodon nlemfuensis and Digitaria decumbens .

Pests and diseases

Susceptible to root-knot nematode (Meloidogyne javanica) and stem -gall nematodes (Pterotylenchus cecidogenus) in Brazil and can destroy pure stands within 2 years.  False rust or wart disease caused by the fungus Synchytrium desmodii is serious in Colombia and Ecuador, reducing soil seed reserves and seedling survival and yields by 70%.  Foliar blight (Rhizoctonia solani) has been seen in the humid regions of South America.
Under experimental conditions, mycoplasma -like organisms have caused little leaf, or witches broom.

Ability to spread

Will spread, and may become dominant in pastures, particularly on acid infertile soils and where grazing pressure is low.

Weed potential

Not considered to possess significant weed potential.

Feeding value

Nutritive value

Top

Has only moderate nutritive value although fertilising may improve this.  Digestibility and intake are reduced by high concentration of condensed tannins.  CT concentrations ranged from 4-7% of DM based on ovalifolium standards, but analyses using less specific measurement techniques suggest much higher tannin concentrations (19-30%).  Animal performance and palatability data suggest that ovalifolium CTs may be highly astringent, binding relatively large amounts of protein/unit of tannin in comparison to CTs from other species (eg. Leucaena leucocephala ).  New accessions show higher N (2.8-3.3%) and lower tannin than CIAT 350 (N = 2.75%).

Palatability/acceptability

Cattle will reject the legume when first introduced to it.  Palatability and intake are low but legume intake may increase as grasses mature later in the season.  Pen studies with sheep (wethers) show that variation in intake may be asymptotically related to level of DM on offer.

Toxicity

No reports of toxic compounds were cited.

Production potential

Dry matter

Dry matter yields of around 7 t/ha/yr have been recorded.  In the Colombian savannas, yields of legume in a grass-legume sward (Andropogon gayanus , Brachiaria decumbens and B. humidicola ) were 8-9 t/ha, with legume contents of 42-46%.  Annual DM yields for mixtures of the legume with Brachiaria decumbens or B. humidicola were 7.2 (50% legume) and 7.3 t/ha (38% legume ), respectively.  DM yields in regional cutting trials in Colombia and Mexico, in locations with 5-6 months dry season, were 0.002-0.14 t/ha/every 12 weeks;  at locations in Colombia and Venezuela, with a dry season of only two months, DM yields were 0.15-0.61 t/ha/every 12 weeks.

Animal production

Top

Under grazing, produces 100-700 g/head/day.  In the Colombian savannas, mixed pastures have produced LWGs of 264 kg/ha, 32% higher than from grass -only swards.  Animal production has been increased by sowing ovalifolium with Brachiaria humidicola to produce LWGs of over 500 kg/ha/yr.  Results from milk production trials are variable, with a 10% gain reported in one trial, but slightly lower production in another trial.  In both cases the companion grass was Cynodon nlemfuensis .  As a companion legume , ovalifolium supported lower milk production than Stylosanthes guianensis , Centrosema macrocarpon and Arachis pintoii.

Genetics/breeding

The sub-species contains little morphological variation, but there exists considerable variation for establishment vigour, DM, seed yields, flowering time, drought tolerance and forage quality.

Seed production

Hand harvested seed is marketed in Singapore.  At latitude 16°S, in the Brazilian savannas, flowering occurs from March to early May.  Seed production can be high with adequate moisture, with yields of over 400 kg/ha recorded at higher latitudes, but only 75-170 kg/ha at 3ºS.

Herbicide effects

No information available.

Strengths

  • Very well adapted to acid, infertile soils.
  • Combines with creeping Brachiaria grasses.
  • Persistent under heavy grazing.
  • Good shade tolerance.

Limitations

Top

Other comments

    

Selected references

Schultze-Kraft, R. and Benavides, G. (1988) Germplasm collection and preliminary evaluation of Desmodium ovalifolium Wall. Genetic Resources Communication, No. 12.

Schultze-Kraft, R. (1992) Desmodium heterocarpon (L.) DC. ssp. ovalifolium (Prain) Ohashi. In: 't Mannetje, L. and Jones, R.M. (eds) Plant Resources of South-East Asia No. 4. Forages. pp. 108-110. (Pudoc Scientific Publishers, Wageningen, the Netherlands).

Internet links

Cultivars

Cultivars

Country/date released

Details

'Itabela'
'Macagual'
(CIAT 350)
Brazil (1989)
Venezuala (2001)
Southeast Asian commercial variety known as CIAT 350.  Seed is commercially available in southeast Asia, where ovalifolium is used as ground cover in plantation crops.
'Maquenque'
(CIAT 13651)
Colombia (2002)     

Promising accessions

Top

Promising accessions

Country

Details

CIAT 13089 Thailand Good yields under intermittent flooding;  some resistance to Synchytrium desmodii.  Evaluated widely throughout the tropics.