Desmanthus

Desmanthus
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NOTE: The information in this Agnote must be read in conjunction with Introduction to selecting and using pastures in NSW, which covers information on areas of adaptation, sources of variability, species mixtures, and important issues related to animal health and the conservation of native vegetation.

Pasture type and use	A woody-stemmed, spreading, fern-like perennial. Subtropical, summer-growing legume of Central American origin. Its main use is to provide high-quality stockfeed, as it is a strong competitor with summer grasses.
Pasture type and use	Its woody stems are a disadvantage to its use in crop rotations.
Area of adaptation	North West Slopes and Plains of NSW. It suits slightly acidic to alkaline clay soils. However, it has persisted well on a sandy loam soil of pH(Ca) 5.1 under trial conditions as far south as Gilgandra.
Min. average annual rainfall	550 mm annual rainfall, with a predominance of summer rainfall.
Advantages	Long-lived perennial plant that will withstand heavy grazing. It has a low bloat risk, is deep-rooted, and is drought and cold tolerant (although defoliated by frost). Can provide good ground cover due to its spreading habit which may cover more than 2 metres. Protein content is comparable with that of lucerne (especially the leaf tissue). Has a rapid growth rate, producing up to 10 000 kg DM/ha in the first year.
Disadvantages	Its woody stems are not ideal for crop rotations, but heavy grazing can reduce the problem. Does not tolerate prolonged waterlogging. Does not appear to nodulate freely. This may be a result of shallow sowing due to its small seed size (350 000 per kg), which, during hot weather, can affect rhizobium survival. No herbicides are registered for use on desmanthus in NSW.
Soil requirements	Wide adaptation, from light to heavy soils and from slightly acid to alkaline soils, with a preference for the heavy-textured alkaline soils.
Varieties	The three cultivars listed below have been released. These were once sold as a mixture called ‘Jaribu’ (to provide greater genetic diversity and wider adaptability), but trade of this mix has now ceased. However, seed of these three individual cultivars may be available on the market from time to time: Marc - early flowering, more prostrate, spreading cultivar (height 30–60 cm). Bayamo - tall (100–150 cm), mid-season cultivar, flowering in 110 days. Uman - late-flowering cultivar (about 135 days), height 40–100 cm.
Sowing rates	Sow into moist soil with at least 50–60 cm depth of good moist soil to ensure establishment. Sow no deeper than 1 cm (10 mm). Ensure seed has adequate germination as it is extremely hard-seeded when freshly stripped and must be scarified to raise the germination to 50–70%.
- as only species	2–3 kg/ha
- in mixtures	2 kg/ha
Sowing time	November–February. Avoid sowing too early into cold soil. Sowing after February does not give time for plants to develop before winter. Sowing in the middle of summer can affect rhizobial survival through soil drying out before establishment. Seeds need to remain moist for 3 days to establish.
Companion species	Summer grasses; possibly oversow with snail medic or barrel medic.
Inoculation	Use special Desmanthus inoculum strain CB 3126.
Major nutrient deficiencies	Ensure adequate nutrition by applying phosphorus, sulfur and any other elements known to be limiting.
Main insect pests	No major pests encountered. A small native psyllid can cause leaf yellowing late in the season in coastal areas.
Main diseases	No major diseases encountered.
Management	Plants can be heavily grazed back to small crowns and still give rapid regrowth following good summer rain. It is grazed extremely hard in its native environment. Individual plants can live for more than 4 years, but seedling recruitment can also occur if the plants are allowed to set seed. Under light grazing, desmanthus will flower in both spring and autumn, and produces 200–500 kg seed/ha. Due to its woody structure, cattle make better use of desmanthus than do sheep, which tend just to strip the plant of its leaves. It is palatable to both sheep and cattle.
Livestock disorders of particular note	No livestock disorders encountered.
Additional tips	Try to keep the plant grazed to less than 60 cm tall, to reduce the number of thick woody stems.
Further information	Contact your local District Agronomist.

Acknowledgments

Advice on livestock health disorders was provided by Dr Chris Bourke, Principal Research Scientist, NSW Agriculture, Orange. His contribution is gratefully acknowledged.

Photo: Graham Crocker, NSW Agriculture, Tamworth