Salt-tolerant plant could benefit aquaculture and agriculture

Salt-tolerant plant could benefit aquaculture and agriculture

Murdoch University researchers are leading a project to develop a salt-tolerant perennial crop capable of filtering fish farm waste water while providing feed for livestock.

Associate Professor Alan Lymbery from Murdoch's Fish Health Unit and Group said NyPa Forage – a commercial cultivar of the saltgrass Distichlis spicata – could offer solutions to a number of environmental issues.

"Dryland salinity is a major problem in Australia, affecting approximately 5.7 million hectares of agricultural land – a figure which is expected to rise to 17 million hectares by 2050," Professor Lymbery said.

"The abundance of saline groundwater has prompted interest in growing fish on salt-affected farmland, but disposal of nutrient-enriched waste water is an issue, as runoff can cause problems such as and .

"As a potentially simple and cost effective solution, we looked for a salt-tolerant perennial with a large root system that could filter and trap effluent – one with the yield, protein level and digestibility to become a .

"Having this secondary use makes an integrated aqua-agricultural system more economically feasible for farmers."

Professor Lymbery said tests showed NyPa Forage removed 60 to 90 per cent of total nitrogen loads and at least 85 per cent of ammonia, nitrite/nitrate, total phosphorous and ortho-phosphorus loads.

After fertilisation, crude and digestibility were roughly equal to grass hay and sufficient for maintenance or moderate liveweight gains in adult sheep or cattle – with no accumulation of toxic minerals.

Nutritive value was greatest when the plants were cropped at 21 or 42 days.

"What we need now is to expand these results to a full field study where we can run livestock on fertilised plants and make sure they feed at expected levels," Professor Lymbery said.

He said the project could contribute to the future-food challenge in years to come.

"Aquaculture is the world's fastest growing food production system and is expected to continue to increase in importance as the returns from wild fisheries decline," Professor Lymbery said.

"And as demand for coastal land rises, we may see integrated aqua-agricultural systems become more widespread and profitable."

A paper on the subject can be found here.

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Feb 21, 2013

Dryland salinity is a major problem in Australia, affecting approximately 5.7 million hectares of agricultural land – a figure which is expected to rise to 17 million hectares by 2050," Professor Lymbery said.

Hells bells, I knew that salination of land was still continuing but that is a tripling of the area in less than 40 years from now.

And this has come about through the wholesale clearing of forests and woodlands to make way for European style agriculture on a very different continent. The ground water under vast regions is salty, the salt accruing over upmteen millions of years. The native trees used to suck up most of the rainwater as it percolated down through the soil, and trees with salt-tolerant tootsies could suck relatively fresh water off the top of the water table. Wheat and other crops cannot do this so, since the clearing started, extra water has been reaching the saline water tables.

Feb 21, 2013
NB: I think the ideas and research described in the article are wonderful, I hope it works!

One other way of stopping rainwater from getting down to the water tables would be to grow Cannabis sativa which used to be known as Indian Hemp. Apparently the highly entertaining smokable plant is Cannabis Indica. C sativa has much less THC it seems [though when I was a scruffy hippy running around Kings Cross [NSW] long ago, I'm sure we thought the naming went the other way].

The point is that Indian Hemp needs to make a comeback into the world economy and once again provide the billions of tonnes of plant fibres we need to make paper, cardboard, cloth, and whatever else. The perennial plant has a much bigger root mass than wheat or any of the other grain crops and will be able to stop any more water sinking to the water tables.

I doubt that C sativa is much use as a fodder crop but any spare plant bulk could be baked to produce syngas and biochar [charcoal for soil conditioning.]

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