Small Farms

Neptune legume saviour to saltland

Dr Phil Nichols

A robust new annual pasture legume, named after the Roman god of the sea, has been released, which will help to revive the productive capacity of saltland areas across southern Australia.

The species, Neptune messina, was unveiled at the Wagin Woolorama.

The pasture, which is derived from a wild plant collected in Israel, was selected for release by the Department of Agriculture and Food and the South Australian Research and Development Institute (SARDI), with support from the Future Farm Industries Cooperative Research Centre (FFICRC).

Project leader, department senior research officer, Phil Nichols, said Neptune had demonstrated great potential as a grazing pasture for saline land, while supplying nitrogen to salt tolerant companion grasses.

Neptune has a higher combined tolerance to salinity and waterlogging than all other current pasture legumes,” Dr Nichols said.

“It is suited to winter-wet saltland areas, from sands to heavy clays, which receive more than 375 millimetres annual rainfall with a soil pH of more than 5.5.

Messina will give mixed enterprise farm businesses the option to increase their cropping area by opening up areas that would previously have been unsuitable for livestock grazing.”

SARDI research has shown that Neptune has similar nutritive value to balansa and subterranean clovers, with no toxic chemicals.

“Grazing trials showed that while Neptune was less palatable to sheep than sub clover, resulting in slightly lower live weight gains, it was readily grazed when other pasture species were present, suggesting it is best used in mixed pastures,” Dr Nichols said.

FFICRC analysis estimates that Neptune messina can increase onfarm productivity by up to four dry sheep equivalents per hectare across 600,000 hectares of saltland across southern Australia.

This equates to an increased value of $36 million per annum from additional livestock production and $16.3 million from nitrogen fixation in soils that are currently very deficient.

A key achievement of the project has been to identify a salt tolerant strain of rhizobia to nodulate messina, as other commercial strains cannot survive the high salt levels present over summer in saline environments.

Neptune must be inoculated with this specially developed rhizobium at seeding, preferably using a peat slurry and lime pelleting, to ensure good nodulation,” Dr Nichols said.

In comparison to other pastures, Neptune messina produced around six times more biomass in trials at Darkan and Tambellup than balansa clover and burr medics, the best pasture legumes currently available for saline land. It also performed well in South Australian trials.

Neptune is moderately hard seeded, which enables good germination levels in the year after sowing, while some seed is kept in reserve for germination in future years.

“Its delayed seed softening gives some tolerance of false breaks of season and defers germination until reliable rainfall in late autumn that can flush salts from the soil surface,” Dr Nichols said.

Like many pasture legumes, messina can be affected by redlegged earth mites and aphids, as well as native budworm and powdery mildew.

Limited Neptune messina seed, and its special rhizobium, are now available for purchase from Seednet.

More information is available on the department’s website

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