Arrotas arrowleaf clover
Establishment and management guide for livestock production systems
Arrotas arrowleaf clover (Trifolium vesiculosum) is characterised by high growth and nutritive value during spring and early summer.
Arrotas can provide high quality green feed for grazing animals late in the season when many other pastures have senesced, but it has poor winter production.
Other benefits of Arrotas include increased soil nitrogen, and its role as a disease break crop.
Arrotas is suited to the high rainfall areas (>600 millimetres) of south-west Victoria, Gippsland, Tasmania and the south-east of South Australia. For other areas of slightly lower rainfall, shorter season cultivars are available such as Zulu, Seelu and Cefalu.
Appearance and Habit
Arrotas is an annual legume with a deep tap root system that can utilise subsoil moisture down to 1.3 metres. It is a branching, semi-erect plant with thicker central stems than other clovers.
Young plants appear similar to other clovers but become easier to identify as they mature. Mature plants have leaves that are diamond or arrowhead shaped with distinct white or green V-shaped marks and sometimes indistinct red marks. Its leaves are hairless and have 'saw tooth' like edges.
An aerial seeder, the flower heads are large and consist of many individual flowers. Petals change in colour from white to pink and later to bronze as they mature.
Seed heads remain intact on the stem, with seed being shed soon after maturity. The seeds are slightly larger than those of Balansa and Persian clovers, but smaller than those of subterranean clover.
Arrotas is adapted to a wide range of soil types and performs well on soils with high water holding capacity, but it will not tolerate waterlogging.
Arrotas is not suited to highly acid or alkaline soils and prefers a soil pH in calcium chloride of 5-7.
Each plant produces large quantities of seed, which is over 90% hard at maturity and requires softening to allow germination. The seed can be mechanically softened for sowing.
In the field, high soil temperatures during summer are required to soften the seed. In the second year of an Arrotas pasture, there is only a small amount of natural regeneration, and it is not until the third year that much regeneration occurs. Allowing plants to set seed in the first year is necessary to ensure a seed bank is established in the soil for subsequent regeneration.
Mature Arrotas seed ingested by a sheep can be softened as it passes through their digestive tract and when deposited on the paddock will germi-nate in the following season. Germination of this seed may be patchy and thin.
Pests, Diseases and Viruses
Common pests are the redlegged earthmite, blue oat mite, lucerne flea, cockchafers and slugs.
There are no significant disease or virus problems.
Sheep grazing pure Arrotas pastures experienced no incidence of bloat or redgut during grazing experiments conducted by the former DEPI Hamilton, Victoria, from 2004 to 2006. However, care should be taken when introducing stock to any legume dominant crop or pasture.
Once established in a pasture Arrotas germinates after the autumn rains. While its production in autumn and winter is low relative to subterranean, Balansa and Persian clovers, its spring and early summer production is outstanding.
Arrotas can be incorporated into a mix with annual ryegrasses, forage cereals and perennial ryegrass to improve winter production.
In south west Victoria, Arrotas has produced herbage dry matter yields of over 10 tonnes/ ha/year in seasons with average rainfall in late spring and summer. Its annual growth can exceed subterranean clover and Balansa clover.
Arrotas is a highly digestibile pasture with high crude protein and metabolisable energy levels similar to subterranean clover. Over a two year period at Hamilton, its digestibility was compared with the late-maturing subterranean variety Leura. In the critical early summer period the digestibility of Arrotas was 5-15% higher than Leura.
The digestibility of Arrotas was 5-15% higher than Leura subterranean clover in early summer over two years. Values are means from the 2004/05 and 2005/06 summers at Hamilton, Victoria.
Arrotas provides high quality green feed for stock late in the season. This gives it the ability to maintain high lamb growth rates into summer.
In experiments conducted by the former DEPI Victoria at Hamilton, in 2004-06, lambs grazing pure Arrotas maintained higher growth rates from November to late December than lambs grazing either pure subterranean clover, or a mixture of perennial ryegrass and subterranean clover.
Lambs grazing pure Arrotas continued to gain approximately 100 g/day from January until early February. In comparison, lambs on a pure subterranean clover and a perennial ryegrass-subterranean clover mixture ceased gaining weight in late December because their forage quality was insufficient.
Lambs grazing Arrotas (18 Iambs/ha) gained an extra 8-10 kg between mid December and early February, relative to lambs grazing Leura subterranean clover. Hamilton, Victoria.
The soil should first be tested for available phosphorus, potassium, sulfur and pH to identify fertiliser and lime requirements. Lime should be applied and incorporated prior to sowing if the topsoil pH is below 5.0 in calcium chloride.
One common establishment problem is competition from winter active weeds. Aim to reduce weed populations and seed-set in the year prior to sowing, particularly broadleaf weeds.
Make sure the paddock has minimal trash and if direct drilling into an existing pasture, the herbage residual is minimal.
Purchase high quality certified Arrotas seeds. which has already been softened. Inoculation of seed with Group C fil/SM 409) inoculum is vital be-fore sowing. Seed can also be treated for protec-tion from red-legged earth mite.
Sowing is generally between the autumn break and mid winter. Early sowing will give faster establishment and help produce more dry matter through winter.
Arrotas can be successfully established by direct drilling. I he reduced soil disturbance of direct drilling limits the germination of competing winter weeds.
The recommended sowing depth is S mm. Seeds planted at a depth greater than 10 mm are unlikely to establish. Light harrowing with chains or rolling may improve soil seed contact.
Drilling seed with 10-15 kg P/ha as single or triple superphosphate can be beneficial in soils with a low to moderate available P level.
When sowing a pure sward or into an existing pasture, a rate of 8-10 kg/ha is recommended. When sowing as part of a pasture mix, use 2-6 kg/ha of Arrotas, and consider a lower rate of winter-active species to reduce competition with Arrotas.
High plant densities of Arrotas at establishment help increase winter production and persistence.
Fertiliser rates will depend on soil nutrient levels indicated by a soil test. Aim for an Olsen P of at least 15 mg/kg. Available K should be at least 130 mg/kg for a sand, and 160 mg/kg for a clay loam. Trace elements such as molybdenum should be included in the fertiliser mix if there are known deficiencies.
During the early growth stages, Arrotas is very susceptible to pests and weed infestations. A pre-emergent herbicide should be considered, mixed with an insecticide to provide a residual control against insects.
Regularly inspect the pasture for weeds, pests and root diseases so action can be taken if required. A maintenance application of fertiliser is recommended each year, based on recent soil tests, stocking rates and herbage production.
Grazing should be deferred until the plant is well anchored.
The paddock can be set stocked lightly through the winter, to assist in controlling competition from winter active species if grown in a mix.
For areas intended as long term pasture, gra7ing should be deferred from the beginning of flowering in the first year to ensure maximum seed set. Gra7ing can be reintroduced about six weeks after flowering when the seed heads are dry. Sheep can carry the seed through their gut and deposit it to other paddocks.
Silage and Hay
The sward should not be cut for hay in the establishment year if the stand is intended for long term pasture. This is to ensure that it flowers and large amounts of seed are set.
The erect growth habit, good regrowth and high digestibilty of Arrotas make it an ideal species for silage and hay, however the thick stems can make drying difficult. A mower-conditioner can speed up curing time and shorten the time to baling.
Continue to control weeds by grazing or applying appropriate herbicides or a combination of both.
Remember that without a means of seed softening Arrotas will not regenerate until year three (second autumn) after establishment. Consider the option of either growing an annual crop, or direct drilling phalaris or a winter-active tall fescue. This provides excellent establishment of the grass component in year two, allowing Arrotas to germinate in year three as a companion legume.
Arrotas will regenerate from hard seed reserves and should be allowed to set seed every few years to replenish the seed bank.
Pastures that consist of pure or near-pure legume fix large amounts of nitrogen. This carries the risks of nitrate leaching into groundwater, soil acidification, and a build-up of nitrogen-loving weeds such as thistles, capeweed, and annual grasses. The first two years of a pure legume pasture do not carry these risks, because the quantity of new nitrogen is relatively low, and most of it is safely contained within the legume plant in late winter when leaching is most likely to occur. However, for the third and subsequent years, the paddock should either be sown to a crop or oversown with a vigorous non-legume such as perennial ryegrass to use the extra nitrogen.
Producer Case Study 1
The Vennings of Morgiana, south west of Hamilton, Victoria, operate a fine wool Merino enterprise. They were involved in a legume pasture:crop rotation trial on their farm in which Arrotas was waled. Pleased with the performance of Arrotas, they trialled Arrotas in a pasture mix.
In early May 2005 the Vennings direct drilled (dry) a 13 ha paddock with Arrotas (12-15 kg/ha), Leura Subterranean Clover (4 kg/ha) Holdfast Phalaris (1 kg/ha) and a mix of Resolute and Flecha MaxP Tall Fescue (4 kg/ha).
The paddock was of mixed soil types and topography, with deep black ground on the banks, red slopes and a grey loam on the flats.
No fertiliser was incorporated at sowing, but superphosphate was applied at 200 kg/ha three months prior to sowing, as had been the practice for the previous five years.
At the two leaf stage the pasture was sprayed with a broadleaf herbicide to control thistles, and an insecticide to control cockchafers and red-legged earth mite.
The following stocking pattern was used on this 13-ha paddock:
- Midjune to mid August - 100 ewes lambed down to 90 lambs
- Mid August to early September - 180 ewes and 160 lambs
- Early September to mid November - 300 ewes and 320 lambs
- From mid November there was no further grazing of the paddock until the Arrotas flowered.
Despite a rainfall of only 329 mm between sowing in May and mid December, the Vennings have been pleased with:
- Better winter performance than other newly establishing perennial pastures (phalarls and tall fescue)
- Ewes gaining condition and lambs some of the heaviest across the whole farm.
- Lambs can be shorn later as they are free of grass seed
- Arrotas competed against canary grass (Phalaris minor and P. paruduxa) better than subterranean clover.
- The ability of Arrotas to be grazed hard so canary grass could be eliminated without affecting the seed set of arrowleaf .
- Arrotas growing in a mix where grasses remove nitrogen and provide summer cover for the paddocks.
Arrotas has persisted where it was allowed to set seed. The Vennings are considering using Arrotas as a break crop within cereal rotations on their well-drained black soils that are unsuitable for other legumes
Producer Case Study 2
At Stratford in Gippsland, Victoria, Tim Buxton, in partnership with his family, operates a fine wool Merino enterprise. Tim became involved in Arrotas through literature and speaking to Tasmanian plant breeders. Arrotas appealed to Tim as a late season pasture for weaner lambs.
Just before a rain in August 2005 Tim direct drilled a 7 ha sandy loam paddock (pH 5.7) with Arrotas (5 kg/ha) and Howlong Cocksfoot (4 kg/ ha) and a double super sulphur mix with molybe- dunum at 100 kg/ha.
A preventative insecticide was applied in conjunction with the pasture knockdown before sowing and the Arrotas seed was also treated with Gaucho" for prevention of red-legged earth mite. The paddock never encountered any insect or significant weed problems during the growing season.
The Arrotas flowered in late November and early December and stood at about 70 cm high. 300 lambs were weaned onto the paddock in early December, and grazed the paddock for 3 weeks, equating to a carrying capacity of 43 weaners/ha for that period. Considering only 225 mm of rain had fallen from the end of August until the end of December, the Arrotas provided high quality feed when many other pastures had dried off.
With limited rainfall after the grazing in December the paddock did not regrow and mature ewes cleaned up the residual left in the paddock.
The following year, Tim sowed more Arrotas with cocksfoot and in the future plans to incorporate Arrotas with a short term ryegrass for winter fodder and silage. He also plans to manage future grazing to allow regeneration of the species.
Stephen Pasture Seeds and Tasglobal Seeds have the distribution rights for Arrotas seed, and can provide agronomic advice regarding this variety. Contact SPS on (03) 5335 8055 or sps@ netconnect.com.au, or Tasglobal Seeds on (03) 6397 3184 or firstname.lastname@example.org.
For more on the information contact the Department of Economic Development, Jobs, Transport and Resources, Private Bag 105 Hamilton, Victoria, 3300 Australia. Telephone 03 5573 0900 or Fax 03 5571 1523.
Evans, P (2006) Arrowleaf clover. Victorian Department of Environment and Primary Industries, Agriculture Notes AG0576.
Hall E, Smith S (2005) Fact Sheet: Arrowleaf Clover, Tasmanian Institute of Agricultural Research
Thompson RB (2005) Arrowleaf clover. Primefact 102, NSW DPI
Zhang X, Evans P, Riffkin P, (2004) Performance of annual pasture legumes in cropping rotations in the cool temperate zone of south-eastern Australia, Australian journal of Experimental Agriculture, 44, 863-871
Meat and Livestock Australia and the Department of Economic Development, Jobs, Transport and Resources (Victoria) for funding the research program.
Michael Grant, Stephen Pasture Seeds, Ballarat, Victoria
Bob Reid, Tasmanian Institute of Agricultural Research, Tasmania
Robert Dent, Tas Global Seeds, Tasmania
Pedro Evans, formerly of DEPI Hamilton, Victoria (now DLF Seeds, Christchurch, New Zealand) Simon Hunt, Stephen Pasture Seeds, Stratford, Victoria
Bradley Venning, Morgiana, Victoria
Tim Buxton, Stratford, Victoria
Gubbins family, Murroa Experimental Site, Hamilton, Victoria
Russell Cavill, Murroa Pastoral Company
Suggested citation: Kennedy AJ, Thompson AN, Drum JA, McCaskill MR (2009) Arrotas Arrowleaf Clover - Establishment and management guide for livestock production systems. Department of Environment and Primary Industries, Melbourne, Victoria.
ISBN 978-1-74146-833-7 (print)
ISBN 978-1-74217-618-5 (Online)