Scientific name(s)
Trifolium subterraneum ssp. brachycalycinum
Strengths
- Tolerant of heavy grazing under set stocking.
- Vigorous seedlings provide good winter feed
- Very persistent in high rainfall areas and other areas with infrequent cropping
Limitations
- Requires cracking or stony soils to bury its burrs
- Insufficient hardseededness for reliable persistence in tight cropping rotations (1 year crop:1 year pasture)
- Susceptible to germination following ‘false breaks’
- Shallow-rooted, so unable to capture deeper soil moisture and susceptible to premature death in dry springs
Plant description
A prostrate self-regenerating annual pasture legume tolerant of heavy grazing that grows from autumn through to spring.
Pasture type and use
Suited to permanent and semi-permanent pastures and to crop rotations (with at least 2 years between crops). It is best suited to neutral-alkaline cracking or stony soils, while the other subspecies (yanninicum and subterraneum) are better suited to acid soils.
Where it grows
Rainfall
Adapted to winter-dominant rainfall area of southern Australia with annual rainfall 425 -800 mm. Midseason varieties suited to medium rainfall zone, later flowering varieties suited to higher rainfall zone. Can also be grown under irrigation.
Soils
Prefers well-drained, neutral-alkaline (pHCaCl 6.0-8.5), cracking and self-mulching or stony loams and clays.
Temperature
Adapted to the agricultural areas of South Australia, Victoria, New South Wales and parts of south-east Queensland on appropriate soil types with sufficient winter rainfall. Good frost tolerance.
Establishment
Companion species
A range of perennial and annual grasses, lucerne, subterranean clover ssp. subterraneum, biserrula, rose clover, purple clover, balansa clover, Persian clover, barrel medics and burr medics, depending on soil type.
Sowing/planting rates as single species
5-15 kg/ha.
Sowing/planting rates in mixtures
3-8 kg/ha, depending on the number of mixture components.
Sowing time
Sow April-June, into moist soil following good weed control. Shallow sowing (<40 mm) is essential.
Inoculation
Commercial Group C (subterranean clover). Granular clay inoculants can also be used. Will biologically fix about 25 kg nitrogen per tonne of dry herbage produced.
Fertiliser
Phosphorus (with potassium or sulphur on deficient soils) at sowing – levels dependent on soil tests.
Management
Maintenance fertliser
Annual applications of superphosphate (with potassium on deficient soils) are required to achieve maximum productivity. Levels are dependent on soil tests.
Grazing/cutting
Thrives under set stocking and can be grazed moderately hard while flowering. Likely to be shaded out from more erect plants under lax grazing. Can be cut for hay.
Seed production
Requires vacuum harvesting. Seed yields of up to 1000 kg/ha can be achieved under ideal conditions.
Ability to spread
Slow spread from site of sowing. Can spread by burrs attaching to wool.
Weed potential
Its slow rate of spread, its preference for moderate-high fertility soils and specific rhizobia requirement gives it low potential as an environmental weed. It is readily controlled by a range of broadleaf herbicides within crop.
Major pests
Redlegged earth mite is a major pest, particularly at plant establishment, where it can kill emerging seedlings, but also causes damage in spring. Timerite® has proved an effective means of control. Lucerne flea and blue green aphids can also cause damage in spring. Refer to chemical labels for suitability and recommended rates for insecticides.
Major diseases
Some cultivars are susceptible to the foliar disease clover scorch (Kabatiella caulivora), found in high rainfall, humid areas. Other foliar diseases in higher rainfall areas include leaf rust (Uromyces trifolii-repentis), powdery mildew (Erysiphe polygonii) and cercospora leafspot (Cercospora zebrina). Several root rots can attack subterranean clover, causing most damage to emerging seedlings and young plants. They include Phytophthora clandestina, Fusarium avanaceum, Pythium irregulare and Rhizoctonia solanii.
Herbicide susceptibility
Refer to chemical labels for suitability and recommended rates for herbicides registered for use on subterranean clover.
Animal production
Feeding value
Excellent as green feed with in vitro digestibility in the order of 70% and crude protein over 20% until mid-flowering. Quality reduces once plants hay off. Dry herbage feeding value over summer is less than maintenance value (often < 50% in vitro digestibility) although animals may be able to obtain sufficient energy and protein by digging up seed burrs.
Palatability
Readily consumed by livestock, either as green or dry feed.
Production potential
Vigorous seedlings provide good early season production. Later flowering varieties capable of more than 10 t/ha annual production in long-season environments.
Livestock disorders/toxicity
No commercially available varieties of ssp. brachycalycinum subterranean clover are oestrogenic and ewe infertility will not be affected. There have been isolated reports of cattle bloat on very clover-dominant subterranean clover pastures.
Cultivars
| Group | Cultivar | Seed source/Information |
| mid-season maturing | Mintaro | - |
| Clare 2 | Seed Distributors | |
| Clare (older) | Australian Herbage Plant CultivarsSeedmark | |
| Rosedale (older) | Australian Herbage Plant Cultivars | |
| late maturing | Antas  | PlantTechSeedmarkStephen Pasture Seeds |
| Koala (Nuba) | Australian Herbage Plant CultivarsSeed Distributors |
Denotes that this variety is protected by Plant Breeder's Rights Australia
Further information
www.agric.nsw.gov.au/reader/pasture-varieties-nsw www.agric.nsw.gov.au/reader/past-varieties/p2516a.htm www.agric.nsw.gov.au/reader/past-templegume/dpi268.htm www.dse.vic.gov.au/dpi/nreninf.nsf/9e58661e880ba9e44a256c640023eb2e/685fbb553814c08bca256f35000a42b3/$FILE/AG0706.pdf www2.dpi.qld.gov.au/pastures/17945.html Registered cultivars of subterranean clover - their characteristics, origin and identification (1996). Agriculture Western Australia Bulletin No. 4327, pp. 61.Pasture Legumes for Temperate Farming Systems – The Ute Guide, Top Crop Australia. (2004). (Primary Industries and Resources South Australia/ Grains Research and Development Corporation), pp. 147.
Antasseedmark.com.au/files/sub-clover_antas1.pdf Clare 2www.seeddistributors.com.au/cl-clare2.html Koala (Nuba)www.seeddistributors.com.au/cl-koala.html Mintarowww.dpi.nsw.gov.au/aboutus/resources/factsheets/primefacts/mintaro-subclover
Phyto-oestrogenswww.agric.wa.gov.au/content/aap/sl/hea/sheepinfertfarmnote.pdfDiseasesFungal diseases of pasture legumes in Western Australia (1989). Department of Agriculture, Western Australia, Bulletin No. 4133.www.agric.wa.gov.au/content/past/pl/clo/fn2006_cloverscorch_myou.pdf www.dse.vic.gov.au/dpi/nreninf.nsf/9e58661e880ba9e44a256c640023eb2e/12813063fde4812eca256f0f0009b426/$FILE/AG0725.pdf www.agric.wa.gov.au/content/pw/ph/dis/past/fn068_1991.htmwww.dse.vic.gov.au/dpi/nreninf.nsf/9e58661e880ba9e44a256c640023eb2e/9c6ba16bd3070389ca256f35000a41ab/$FILE/AG0724.pdf
Acknowledgements
Hayley Norman, CSIRO, for comments on feeding value.
Author and date
Phil Nichols (DAFWA) and Brian Dear (NSW DPI)
July 2007
