scabra Vogel -
The shrubby stylos are exceptionally hardy plants ideal for extensive grazing. They establish easily, keep green leaf into autumn, and persist through drought due to their deep tap-roots.
The shrubby stylos are sown in the tropics and to about latitude 27°, in districts receiving 600-1600 mm of rainfall They will grow on a wider range of soils than stylos; although most commonly sown on very infertile sandy soils, they can also thrive on the lighter types of brigalow soils, but cannot tolerate waterlogging or heavy cracking clays.
The shrubby stylos grow into small erect shrubs up to 2 m high if ungrazed, but in the paddock they usually grow 30-40 cm high with a closely eaten crown on a single stem.
Although the shrubby stylos were originally regarded as relatively unpalatable, being eaten only in autumn, Seca is eaten throughout the year. The feeding value of leaf and flowering heads is high, and is well maintained into the dry season.
Usually 40-60% of the seed is treated to break hard seed, but it needs no special inoculation. It is usually broadcast into burnt or heavily grazed native pasture in November-December in the north, or surface sown into rough seed-beds in the southern speargrass region.
In the north, superphosphate is not used as stylos are generally sown only on soils with phosphorus above 4 ppm; phosphorus needed for animal growth is fed as supplement during the growing season.
Grazing management is simple as the plants seem able to survive any amount of abuse. Fire and frost can destroy the top growth, but the plant reshoots from the base or regenerates from seed in the ground. A leaf disease (Botrytis) has caused deaths in large leafy shrubby stylo in wet weather in late autumn.
Of more importance is the loss of native grasses in heavily grazed stylo paddocks. Grass-legume balance can be maintained by lightert stocking, burning and inclusion of more grazing tolerant grasses such as Sabi grass or Indian couch.
Fitzroy was an early-flowering shrubby stylo for central and southern Queensland, but it succumbed to anthracnose.
Seca was released for the lower latitudes, being very late-flowering. However, since its release, there has been a change in type as Seca now appears able to flower at any time that there is moisture and warmth; flowers are often seen on plants in spring in subtropical districts.
Commercial Seca seed produces a plant that seems to be more leafy than the original stemmy release. Seca has field resistance to the common types of anthracnose (Colletotrichim gloeosporioides) from a single source of gene resistance, but there is considerable worry that the Seca already planted over a large area would be susceptible to an outbreak of new or mutated races of anthracnose.
Siran was bred with four sources of resistance to anthracnose. While Siran is leafier than Seca, the latter still accounts for the bulk of commercial seed production. Siran should be included in stylo plantings to provide insurance against devastation from anthracnose attack.
A common recommendation for stylo plantings in north Queensland is 2-3 kg/ha of a legume mix cosisting of 50% shrubby stylo (mainly Seca with 10-20% Siran) and 50% of a mixture of Caribbean stylo (Verano and Amiga) and Wynn cassia. Some seed of Sabi grass may improve pasture persistnce.
In colder regions and on heavier soils, the Caribbean stylos have been replaced by the Caatinga stylos.
|Creator: Ian Partridge
Date created: 07 April 1998 Revised:15 January 2003