A short history of salinity management in WA

Salinity might have slipped off the radar for some but it’s not going away. A recent tour of salt country organised by Katanning Landcare found five farmers who have made a significant investment in saltland management over the past 10-20 years, all with beneficial outcomes.

Deep drains

The bus tour with Todd Gray and one of his deep drains

The first farm is owned by Todd Gray who has been using deep drains at his Fence Road property east of Dumbleyung. The drains end at a second farm also owned by Todd, where it evaporates over summer. The history of salt in the district is evident at this second property which was cleared in 1910 and went salty in 1912. As if surrounded by a timeline, Todd points out trees he planted with his Aunty in 1991 after they saw salt pop up for the first time at the Fence Road property. However, when Todd invested in deep drains, it wasn’t just salinity but also waterlogging that was causing problems.

“Every time you had 7-8 mm of rain, you’d get big puddles everywhere,” he said. “We got the drain put in and it didn’t take long at all for the waterlogging to stop. It was amazing how quick it was. It’s made a huge difference.

“I don’t think it’s going to fix the salt. It’s helped it for sure and it’s given us options. I had silverosa Lucerne that was going really well until the 2016 floods. I’ll have another crack at it this year.”

The drains were part of a scheme involving 13 other farmers designed by Waters and Rivers and supported with funding from the WA Government. The scheme saw 48 kilometres of drains installed in the early 2000’s.

“We pay an annual levy per kilometre for maintenance and I’ve added another four kilometres off my own back. There were breaches with the first drains where it had been graded too low so we had to make the banks higher. They’ve stabilised since the bluebush has come up.  It’s not an insignificant cost but I think it’s well worth it. Maintenance is only going to be needed once in decade I hope.”

Covering bare scalds on hostile saltlands

NyPa Distichlis growing on a hostile salt flat

Around the same time Todd was planting trees with his Aunty, Wogolin farmer Raymond Matthew was planting a new grass called NyPa distichlis on some of his toughest salt country.

“I got involved with this grass in 1993 when we received our first plant,” Raymond said. “It’s the only plant I’ve found that will grow on country this harsh. To get something to grow on this was just unreal.”

NyPa is a C4 grass that doesn’t store salt in the plant. Instead it exudes salt which you can see on the leaves.

“It’s got to have heat to survive and it has to have salt. If you try to plant it in a freshwater environment it will get outcompeted.”

The plant has no seed and spreads with runners, so propagation has been it’s Achilles heel. Raymond initially put it in with a shovel before buying a vegetable planter that could plant a hectare per day.

“This was all put in a 1 metre spacing and we worked on a 50% strike rate, so one every 2 metres. A sandy area I did covered up in three years. It will grow quicker in sand compared to clay.

“Sheep will supplementary graze it but at best it’s maintenance feed I would think. A bloke in SA says his cattle love it and they’ll take it down to the ground.”

“On this country if you put sheep in here it powders up and blows, but you can see how it anchors the ground same as any stubble. And at one site where we planted a bare scald, we’re getting barley grass and ryegrass back in there.

“The main benefit is erosion control and we work on the fact that it’s using moisture. And if you get some grazing it’s a bonus. At least it’s something on country that we had nothing on before.”

Oil Mallees

Oil Mallees in Toolibin

About 20 kilometres south west of Wogolin is Toolibin where Cam White planted oil mallees in the 1990’s.

“The idea was that we’d be able to make a fortune out of oil!” Cam grinned.

With a decline in rainfall, it’s hard to know what impact the trees are having on the spread of salinity. However, Cam has a fair bit of anecdotal evidence to go by. That includes one property nearby where “a heap” of alley trees were cleared.

“It came back quite salty. Salt-bush has come straight back so I’ve got a feeling that it’s keeping the status quo.”

The experience has made Cam think twice about clearing two out of every three rows on his own property to fit the modern-day boomspray between trees. He’s now planning to only remove every second row.

“I’m not sure if this would have gone salty here, but I know it’s taken a lot of moisture because there’s a dam in the next paddock that’s freshwater, so the groundwater’s gone down far enough that the groundwater doesn’t sit in the bottom of it.

“Some trees on the farm, ten years ago you wouldn’t think they would still be here, but they are.

“There’s been no salt come up since we’ve had the trees in. They were all heading that way. If we’d done a trial I’d say salt would have come up at some stage.

Apart from issues with mustering through trees, the alleys have their benefits.

“We get a good winter grazing between the trees. It’s basically barley grass, ryegrass, a bit of everything. We still put fertiliser on it. They come in handy when you’re shearing, and if you’ve got a storm coming you can put them in here.”

And now it seems there might be a future for oil mallees after all.

Chaff

A treatment of oat husk chaff (left) has had a dramatic effect on the salt country

Close to Wagin we found Raymond Edward who took us to sites where he spread oat husk chaff 15 years ago. The chaff was a foot deep spread with a bucket, and the sites totalled 25 hectares. There was an obvious response to the treatment which Raymond saw within a year of application, and it’s helped the establishment of grasses and saltbush. At the time the chaff was available for free, but that is no longer the case. However, it may be an option for chaff dumps.

Eyres Green salt bush

The final stop was at Woodanilling where Gradyn Wilcox cleared dead trees from 120 hectares in 2005 and established saltbush.

“The first twenty hectares we direct seeded a variety of salt bush with tall wheat grass. From 2007 we’ve crept across the paddock planting Eyres Green saltbush. They grew like weeds for the first two or three years until they used up all the moisture.

“It was 70% scald but now you’re battling to find any. The economist worked out that it would be 11 years payback, so theoretically we’ve got our money back.”

Gradyn said that his cattle seemed to do better with the saltbush compared to sheep, who often found the saltbush out of reach.

“The cattle have done really well. They seem to like it and I think they can cope better with the salt load.”

Gradyn found that benefits started almost immediately after the first ripper mound was put in, which slowed the wind speed.

“Even in winter the top of the ground is always shifting in the salt country. It seemed to be that once you put the first ripper in and started to manage the livestock it seemed to make a big difference. Now there’s very little wind down here.”

Eyres Green saltbush at Gradyn Wilcox’s farm in Woodanilling

Finding the right site for saltbush can make the difference between success and failure.

“This site was almost ideal for saltbush because it’s pretty bad but not terrible. You’ve got a bit of hope here but our samphire country doesn’t grow very good saltbush.”

Event organiser Ella Maesepp said the tour only scratched the surface of the incredible depth of knowledge and experience around the management of salinity. However, upfront costs are a major impediment to getting systems installed at the required scale.

“Salinity is still a major issue, it still needs significant investment and we need to ensure that we are learning from the past to get the best results moving forward.”

The event was supported by Katanning Landcare, though funding from the Australian Government’s National Landcare Program.

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