Pasture legume revives saline areas

The new annual pasture legume Neptune messina on show at the 2017 Wagin Woolorama.
The new annual pasture legume Neptune messina on show at the 2017 Wagin Woolorama.

A new annual pasture legume could help revive the productivity of salt and areas across southern Australia.

Neptune messina is the first cultivar of messina and was derived from a wild plant collected in Israel.

The legume is suited to winter wet saltland areas of southern Australia with greater than 374 millimetres of annual rainfall and a soil pH greater than 5.5. 

Woodanilling farmer Graydn Wilcox grew the new variety last year as part of a demonstration trial.

He said it had performed very well on the degraded salt flats on his farm where he runs 4000 sheep.

“We have been missing a good pasture legume and in the strip trials we ran with Neptune you could see a big difference,” Mr Wilcox said.

Department of Agriculture and Food (DAFWA) director of sheep industry development Bruce Mullan said Neptune had the potential to transform productivity of up to 600,000 hectares of saline or waterlogged soils in WA and nationally.

“It has a higher combined tolerance to salinity and waterlogging than all current pasture legumes and a higher salt tolerance at germination than all other current pasture legumes,” he said.

“It can be safely used for grazing, poses no weed threat and will supply nitrogen to grasses and other pasture components and its use could provide stocking rates of up to four DSE per hectare, depending on location.”

The pasture was selected for release by DAFWA and the South Australian Research and Development Institute (SARDI), with support from the Future Farm Industries Co-operative Research Centre (FFICRC).

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

“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,” he said. 

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 liveweight gains, it was readily grazed when other pasture species were present, suggesting it is best used in mixed pastures,” Dr Nichols said.

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 about six times more biomass in trials at Darkan and Tambellup than balansa clover and burr medics, the best pasture legumes 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.

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

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

Seednet WA territory manager David Clegg said there had been strong interest in the pasture legume, with growers “lined up” ready to plant messina.

“We had very successful seed production in 2016 and that seed is  being cleaned so we are still waiting on final quantities,” he said.