5 May, 2021
Managing Soil Erosion
EARLIER this month, Longreach Landcare and Desert Channels Queensland (DCQ) hosted a field day to discuss previous erosion work and pasture recovery at Warwick and Rosemary Champion’s property, Longway.
Darryl Hill is highly recognised throughout Australia as one of only a few qualified instructors in running grader workshops for soil conservation, he has extensive knowledge and experience in gully remediation and erosion control works.
Eighteen months ago, DCQ and Landcare took erosion control expert Darryl Hill out to Longway, as were concerned about water running down a slope and causing erosion.
The Champions wanted to improve infiltration of water on areas of the property and stop the erosion, get better pastor cover, and soil condition.
Mr Hill is highly recognised throughout Australia as one of only a few qualified instructors in running grader workshops for soil conservation, and has extensive knowledge and experience in gully remediation and erosion control works.
Mr Hill has many methods on how to stop soil erosion, including building contours in the land, to slow down the water and try to get it to soak down in the ground.
Landcare Facilitator at DCQ, Doug Allpass said it was better to have the water in the ground, than running off the property and into a gully.
“What they have done, is with a grater, he dug trenches that are 20m long and in a brick formation,” he said.
“This formation allows the water to stay in the trenches and hopefully sink into the ground.
“You can't stop water, it has to go somewhere, but these contours slow it up, the formation is trying to maximise the best benefit from the rain that you get.
“If these trenches are not here and you get 50mm of rain, then you may lose 75 per cent of it, but if you have these trenches on the land then you may only lose 25 per cent.
“Rain is really scarce out here so you have to make the best use out of it that you can.
“It's the type of ridge that loses vegetation, as it’s hard and it’s stony, but if you can put this sort of stuff in it slows it down and wets those sorts of patches,” said Mr Allpass.
Grazier and owner of Longway, Mr Champion said the contours had been in for about two years and the seedlings had begun to take inside the trenches.
“This is the first decent bit of rain we have seen on these contours,” said Mr Champion.
“It looks like it has guaranteed its future, as there looks like a lot of growth and seeding going on.
“Hopefully in time the plants will spread in between these trenches and get further established.
“The contours were done on problem areas on the property, where it is growing little vegetation,” said Mr Champion.
The idea with the contours is to try to get permanent foliage established and more ground coverage of deep-rooted plants.
Breaking the surface with the trenches allows more moisture to penetrate the ground to give a decent start to plants.
Mr Hill explained one of the biggest exports in Australia was iron ore, which is topsoil.
“We are currently exporting 600 million tons of topsoil per year as an estimate off the Australian coastline,” Mr Hill said.
“Another big export in Australia is water but that’s renewable, as the next cyclone will come back, what is not renewable is those soils that are in those water flows, and it is estimated that is costing the economy 600 million per year in erosion.
“Erosion is an Australian wide environmental issue, but it has the least media image, everybody has heard about timber dieback or solidity or weeds in a particular region, but no one seems to understand erosion.
“I don’t care how big a weed problem is in a region, because if the government threw enough money at it, they could fix it, whereas no economy in the world can fix Australia’s erosion problem.
“Once that soil has gone, we cannot put it back, all we can do is try to slow the rate.
“Now I can't fix one per cent of Australia's erosion, but somebody like Warwick can fix one per cent of his property, then overall we are having a win.”
Mr Hill explained that Longway was an example of pastor improvement through water retention.
“There is no obvious erosion, but they are losing soil here on this property through the wind,” said Mr Hill.
“My big issue is that these roads are all below ground level, so they are intercepting the water flows and diverting the water back down in the creeks.”
Mr Hill explained that the issue today was a slightly different perspective, but still tied in because ground cover would stop the water flows.
“Those water flows are an example, if the water flows off here, it is going to hit that road and flow and it's not going to flow across the ground,” said Mr Hill.
“It is not so bad on the black soil country, but on the red soil country you will drive through, like from Aramac to Charters Towers, there will be good grass on one side of the road and bare areas on the other and that is because the roadway is preventing the areas of those water flows.
“Because there is no grass, the wind blows across now the average Australian shire road (gravel road) and they are losing just under 15 tonnes of soil per kilometer each year.
“Now out of the 15 tonnes, there are five tonnes lost in wind erosion, the majority of the 10 tonnes is lost in water erosion, as water erosion is greater than wind,” said Mr Hill.