Balansa clover (Trifolium michelianum) in Western Australia

Page last updated: Monday, 17 May 2021 - 11:34am

Balansa clover (Trifolium michelianum) is an annual, self-regenerating forage legume introduced from Turkey and has been used in Western Australia since the mid 1980s. It is adapted to most soils where subterranean clover grows well,  tolerates wet, waterlogged conditions during winter, and has low to moderate tolerance to saline soils.

Balansa clover provides valuable grazing for livestock, can be conserved as forage and improves crop yields through nitrogen fixation.

Description

Balansa clover (Trifolium michelianum) is an aerial seeding, self-regenerating, annual forage legume introduced from Turkey, and has been used in WA since the mid 1980s. It is a semi-erect, hollow-stemmed species that can grow to over 0.5m tall, but remains prostrate when grazed.

Leaves are trifoliate and vary greatly in size, shape and leaf marking. Leaflet margins can be smooth or serrated. The variation in leaf marking and shape is due to individual varieties being composed of a mixture of several genotypes. Both leaves and stems are hairless (Figure 1).

Flowers are white-pink in colour and round in shape, measuring 2–3 cm in diameter and each on a separate stem (Figure 1). Balansa clover is an outcrossing species (hence the notable variability in leaf morphology), and is very attractive to bees.

There are named varieties with a range of maturity to cover the 350 to 800 mm rainfall zones.

Photograph of the variable leaf markings and white to pink flower colour of balansa clover
Figure 1 Variable leaf and flower colour of balansa clover.

Seeds vary in colour from pale yellow to dark brown. They are very small, with 1 to 1.4 million/kg (Figure 2).

Close up photograph of the samll yellow-brown balansa seed
Figure 2 Balansa seed

Balansa perfomance

Balansa clover:

  • performs well on a variety of soil types with pHCa ranging from 4.7–8.0
  • typically produces 2–5 t of dry matter per hectare
  • can produce more than 750 kg of seed per hectare in high rainfall environments
  • achieves best production on sandy loams to clays with moderate to high soil phosphorus, sulphur and potassium levels
  • has poor perfomance on deep, acidic sands, and should not be grown on these soils.

Where balansa grows

Balansa is mostly used in medium to high rainfall regions, where it provides valuable grazing for livestock, can be conserved as forage, and improves crop yields through nitrogen fixation.

Balansa is adapted to most soils where subterranean clover grows, and will also tolerate wet, waterlogged conditions during winter.

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Choosing cultivars

Matching cultivar maturity to the environment is important for optimal seed production and this should be reflected in strong seedling regeneration.

Early maturity

  • Frontier was developed from early flowering selections from the cultivar Paradana. It begins to flower around 85 days after a mid-May sowing at Perth and is best adapted to areas with short growing seasons (350–450 mm annual rainfall).
  • Cobra (PBR) was developed from plant selections predominantly from the cultivars Taipan and Frontier with attributes for enhanced seed production. It is early flowering with similar maturity to Frontier.
  • Enduro was developed in South Africa from Paradana material, but flowers two weeks earlier and is of similar maturity to Frontier.

Mid maturity

  • Border was developed from the cultivar Paradana and is intermediate in flowering between Frontier and Paradana.
  • Taipan (PBR) was derived from selections of the cultivars Paradana, Frontier and Viper with attributes for enhanced seed production. It is similar in maturity to Paradana.
  • Paradana is a mid-season maturing cultivar first registered in 1984, flowering approximately three weeks later than Frontier. It has been the basis for development of many other varieties and is still widely grown (suited to regions 425–700 mm annual rainfall).
  • Mamba (PBR) is very late maturity, flowering later than Paradana.

Late maturity

  • Bolta is a late-flowering cultivar, maturing approximately one to two weeks later than Paradana. It is best suited to higher rainfall districts (>550mm annual rainfall) with a longer growing season.
  • Viper (PBR) was derived from selections of the cultivar Bolta with attributes for enhanced seed production. It is similar in maturity to Bolta.
  • Vista (PBR) was derived from selections of the cultivar Paradana on the basis of plant vigour and later flowering. It is similar in maturity to Bolta.

Newly ripened seed of balansa clover contains a high level of hardseededness (typically over 80%), but this seed generally becomes germinable quite quickly over the summer-autumn period.

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Salinity and waterlogging tolerance

See the SALTdeck card for more information.

Balansa:

  • tolerates low to moderate salinity (ECe 2–8 dS/m), typically associated with dense barley grass, but production losses will be evident at the higher end of this range
  • can withstand wet, waterlogged conditions during winter, though it will not tolerate extended periods under water.

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Managing balansa

For establishment

  • Control problem weeds the year before planting balansa.
  • Control red-legged earth mite in the previous spring with the Timerite® package, and control lucerne flea in the establishment year.
  • Avoid areas where residual broadleaf herbicides have been used recently.
  • Immediately before planting, prepare a fine, clod free seedbed to maximise seedling emergence.
  • Sowing:
    • Balansa alone – use inoculated seed (Group C inoculum) at 6–7.5 kg/ha (bare seed at 4–5 kg/ha) as soon as possible after the break of the season. Seed can be dropped on the surface and lightly harrowed or rolled, or drilled at less than 1cm deep
    • Balansa in mixes – use inoculated bare seed (Group C inoculum) at 1.5–3 kg/ha (bare seed at 1–2 kg/ha) with other pasture legumes such as subterranean clover and annual medics.
  • Control insects with bare-earth insecticides at planting (especially lucerne flea and RLEM) for the first few weeks; control pasture aphids such as blue-green aphid, as severe infestations at flowering can reduce seed production.
  • Lightly graze in the establishment winter to help control weeds; get professional advice on herbicide use.
  • Remove stock before flowering, and do not cut for hay in the first year (seed buildup for regeneration).
  • After the seed has matured, the pasture can be grazed (hard seed returned in dung).
  • Heavily graze over summer if the paddock is back to pasture (encourages breakdown of hard seededness)
  • Lightly graze over summer – leaving dry residues on the surface – if the paddock is back to crop (retains hard seededness)

In subsequent years

  • Control red-legged earth mite in spring with the Timerite® package if needed and lucerne flea early in the season.
  • Decide on management for the particular use (see details below):
    • grazing only
    • grazing and hay cutting
    • grazing and seed harvesting.

Grazing balansa

Standard management practice to encourage maximum regeneration of balansa clover pasture involves hard summer grazing. This practice is designed to remove dry plant residues that otherwise insulate the seed and prevent exposure to high soil temperatures which bring about seed softening. However, if balansa pastures are to be cropped, we suggest that dry residues should be retained as long as possible to ensure hard seed levels remain high.

Grazing should be delayed until late autumn and only enough residue removed to allow the passage of seeding machinery. A high proportion of seed (30-40%) will pass through the digestive tract of animals and remain viable.

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Spring Management

Once a seed bank has been established, complete removal of stock in spring is not essential unless seed is to be harvested, but an easing of grazing pressure is advisable. Control RLEM and aphids as required. Cutting balansa clover for hay in spring will yield good quality hay that can be baled without excessive leaf loss.

Digestibility and crude protein levels of balansa clover hay are similar to those of subterranean clover hay. Balansa clover is suited to hay production, since it can provide grazing until late winter and then provide spectacular spring growth.

Regeneration may be poor in the year after forage conservation as seed production will be substantially reduced. Dry balansa clover residues tend to be more digestible than dry subterranean clover, though can decline more rapidly with summer rain.

Harvesting the seed

Balansa clover can be harvested with a conventional cereal harvester provided the stand reaches an adequate height. Crop lifters may be an advantage in thick, lodged pastures. Timing of harvesting is important and stands should not be left too long after maturity as seed is shed from the head.

Dessicant herbicides (e.g. diquat) may be required in some situations if plants or weeds are still green. Swathing can also improve harvest efficiency, however, appropriate timing is important. It is unlikely that large quantities of seed can be harvested with a clover harvester because of difficulties in separating the seed from sand.

Farmers harvesting their own balansa clover seed must ensure that it is scarified before sowing to increase its germination percentage. The use of unscarified seed usually results in a very poor establishment owing to its high hard seed content.

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