Catherine Miller, Stock Journal 9th Oct 2021
FARM FIELD DAY: Thomas Elder Institute ag tech development officer Andy Phelan and SARDI ag tech coinnovation officer Robyn Terry at the Reefinator field day held at Struan last week.
A demonstration site at Struan Research Centre is aiming to turn one of the worst areas on the farm into the most productive.
The 32-hectare site on the northern-most point of the property is where one of six dryland TechnoGrazing systems is located. This is split into eight, 4ha paddocks, which are then made into smaller cells for intensive grazing management.
The area only had 10 centimetres to 20cm of top soil covering the limestone layer but using a Reefinator - which breaks and lifts the rock and then crushes it into smaller pieces - they have increased the soil depth to 20-40cm.
Thomas Elders Institute ag tech development officer Andy Phelan says the aim of the soil amelioration is to maximise pasture production on the shallow soils and prolong the growing season.
"If we can get more plants per square metre and help them get their roots down further we will get longer seasons, particularly when it is drier," he said.
In April, HD Partners Reefinating from Naracoorte used their machine to go over six of the eight paddocks three times, with one receiving a fourth pass. The other two paddocks were undisturbed.
In June, the paddocks were sown with four annual pasture species mixes supplied by PGG Wrightston Seeds; an annual ryegrass and persian clover; an Italian ryegrass and persian clover; a forage ryecorn with an annual ryegrass and an annual ryegrass with sub clover.
"The annual pasture is a bit of a clean-up phase, we might even go with annuals again next year but when we follow with the perennial pastures, that is when we expect to see the biggest difference," Mr Phelan said.
He said there was initially little difference in pasture growth between the eight paddocks but as the season has progressed the reefinated sites were growing more feed.
The Goanna soil moisture probes at the site are also showing that after rainfall events the moisture is infilitrating down in the reefinated areas much quicker than the control areas.
"It will be interesting to see if we get the same sort of response the other way when it dries off," he said.
Mr Phelan acknowledged the Reefinator had been about "for a while"- it was first released in WA in 2015 - but said they wanted to quantify the economics benefits of deep ripping.
"Spending the equivalent to $825/ha, which is what we have done here, may sound scary but it is a long-term investment," he said.
"With the way land prices are, you really need to be getting the most out of what you have got."
The project is part of the five-year partnership between the state government and Elders, which has led to Struan and Kybybolite Research Farms becoming best practice demonstration sites to evaluate the latest ag technology.
REEFINATOR HAS ROCKING RESULTS
WHEN Jethro Hilton and Fraser Day saw a couple of local farmers using a Reefinator from the Eyre Peninsula, they saw a big opportunity to buy one to operate full-time in the South East
In March last year the duo started HD Partners Reefinating and have been working across the region from near Beachport to Keith on shallow limestone country as well as heavily-compacted soils.
The machine, which is three-metres wide, has nine ripper tynes on the front and a stone roller to crush the rock that comes to the surface.
"It acts like a guillotine, pushing down on the rock and fracturing it in the soil rather than trying to pull it all to the surface," Mr Hilton said.
"The best results are from multiple passes, we try and do two or three passes, each pass you get a bit more depth.
"After three passes we sort of average 0.7 hectares an hour for the job."
Mr Hilton said the machine, which is 29 tonnes when the ribbed roller was filled with 6000 litres of water, could operate to a soil depth of 450 millimetres but tended to produce 250-300mm of workable soil.
He said the costs varied between $600/ha and $1000/ha for three to four passes but farmers, many who were starting with just a paddock or two, were pleased with the results.
"Some of the comments are that they are turning almost useless land into some of the most productive parts of their farm," he said.