Barrel medics will grow in colder subtropical areas with reasonable winter and spring rainfall, and have been used in southern Queensland and north-western New South Wales, especially on moderately fertile clays of neutral to high pH.
Medics grow best during the warmer conditions of autumn and spring, but a wet autumn will give a good bulk of feed for winter.
This free-seeding annual legume is a low-growing species, prostrate but not rooting from the nodes. Barrel medics flower in spring after a `vernalisation' period of cold weather, producing small, yellow flowers that give rise to a spiral burr containing 6-10 seeds. The burr has straight spines, and can be combed from wool.
Medics are adapted to a Mediterranean climate with dry summers; they survive wet summers in the subtropics because of their hard seed, but with enough softening to allow regeneration in autumn.
In permanent pastures, medics suffer from competition in autumn from the summer growth of grasses. Reducing this by heavy grazing in autumn, summer drought or by cultivation improves seed germination.
Barrel medics for the subtropics include Cyprus, Caliph, Jemalong, Paraggio, Sephi and Parabinga.
Cyprus and Jemalong were the most popular varieties until the arrival of blue-green and spotted aphid in the late 1970s. Caliph was bred from Cyprus with resistance to blue-green aphid, whereas Paraggio and Sephi were aphid-resistant selections to replace Jemalong. Parabinga is an early-flowering variety with aphid resistance.
Cyprus and Parabinga are early-flowering, and are more suited for drier regions, Jemalong, Paraggio and Sephi being mid-season flowering are more suited to higher rainfall districts. Jemalong is distinguished by the prominent purple-brown splash in the centre of the young leaflets.
Barrel medics may be included in mixtures at 1 kg/ha or sown at up to 5 kg/ha as the sole legume component. They can be sown at a low rate with wheat to improve soil fertility and wheat quality, and also to improve the value of stubble grazing for sheep.
Burr medics are small naturalised species that can cause wool fault.
Snail medics are large species for restoring soil fertility in cropping systems.
|Creator: Ian Partridge,
Date created: 14 April 1998 Revised: 15 January 2003