Mouldboard advances built on experience
GroundCover™ Issue: 117 | Author: Nicole Baxter
Owners: Cliff and Kay Harding
Manager: Tony Harding
Location: Mingenew, Western Australia
Farm size: 6600 hectares (owned), 1720ha (leased)
Annual rainfall: 425 millimetres
Soil types: yellow sand, white sand, gravel and red loam sand
Soil pH: 5.5 to 6.5 (calcium chloride) on the surface and 5.5 to 5.6 at depth
Crops grown: wheat, canola, barley, lupins and oats
Seven years of experience have made Tony Harding even more convinced of the merits of mouldboard ploughing as a strategy for non-wetting sand and weed management
Seven years after putting his mouldboard plough to work to bury non-wetting sand and weed seeds, Tony Harding says the paddock he first treated is still performing better than those yet to be ploughed.
The Western Australian grain grower, who farms near Mingenew in the state’s northern wheatbelt, says paddocks that have been mouldboard ploughed have produced up to one tonne per hectare more grain.
“Mouldboard ploughing allowed us to increase topsoil clay content from 0.3 per cent to as much as 10 per cent, with the added advantage of helping us control weeds,” Tony says.
“The soil now wets evenly, allowing weeds to germinate at the same time, which has helped us to achieve a better weed kill.”
Tony first started mouldboard ploughing in 2009 with a trial, hoping the technique would lift clay from the subsoil to the topsoil and ameliorate his water-repellent sands. At the time, he recalls, the burial of weed seeds was just an added bonus.
Using his nine-furrow Kverneland plough, Tony established a 175-hectare trial in a 327ha paddock that had become infested with ryegrass, radish, brome grass and blue lupins.
During early June 2009, he ploughed moist soil to a depth of 350 millimetres and rolled it before planting wheat. The part of the paddock that had been ploughed yielded 2.5t/ha while the unploughed control area yielded 1.6t/ha.
Since 2009, Tony has ameliorated 1200ha and hopes, in time, to ameliorate all of his land that has non-wetting issues by completing up to 500ha each year, if conditions are suitable.
“Mouldboard ploughing is an opportunistic exercise,” he says. “If the soil is too dry we reduce the area, or keep going if it’s nice and wet,” he says.
For example, in 2013, the plough stayed in the shed because Tony says he did not have any staff with the skills available to complete the job.
“There’s a lot of skill involved in mouldboard ploughing,” he says. “It’s probably one of the only jobs where you need to maintain concentration and some hand-eye coordination to put the machine in the ground at the right time.”
According to Tony, mouldboard ploughs do not work well on GPS. “It can be done, but you spend a lot of time nudging it,” he says.
Using the mouldboard plough is not just a case of pulling one lever at the end of a row, Tony says. There are up to 10 operations required, depending on the plough make, to move it over and place it into the right position.
“If you’re too quick or too slow putting the plough into the ground you end up with a mess at the end,” he says. “I’ve got a couple of bits of railway line welded together that we drag around to fill in any holes [made by the plough].”
Since his first year of mouldboard ploughing, Tony says there have been many lessons learnt.
He says one of the biggest is that there is no such thing as a “bad ploughing job”, with the worst ploughed paddock on his farm consistently out-yielding the unploughed paddocks with non-wetting issues.
“Depth isn’t important, it’s how deep you can invert your topsoil; so while you might want to plough at 355mm, ploughing at 254mm might do a better job,” he says.
Another key learning has been about crop rotation and herbicide use on recently ploughed paddocks. Tony always plants a cereal – wheat, barley or oats – as the first crop after mouldboard ploughing to achieve a good spread of residue across the paddock.
While lupins were initially tried as the second crop after ploughing, they were mainly replaced with triazine-tolerant canola as lupins sprayed with triazine proved too sensitive and died.
Wind erosion was an issue when the first paddock was treated in 2009, but Tony has since developed a technique to counter this. In 2009, he used an Ausplow Deep Blade System (DBS) seeder set on 305mm row spacings to sow the crop in an east–west direction. When the crop had reached the three to four-leaf stage, a westerly wind that reached 90 to 100 kilometres per hour swept through the region, reducing the crop back to its crowns. Fortunately, the crop recovered and went on to yield more than the unploughed control.
To counter wind, Tony now sows across the direction of the wind. He has also fitted splash plates to the front of the DBS seeder to scatter seed across the front of the machine, allowing crops to grow in between the 305mm rows.
Aside from reducing the ‘wind-tunnel effect’, Tony says having crops in the inter-row has helped with any germination issues from seed depth on the soft ground.
To ensure adequate soil inversion, Tony says it is important to prepare paddocks for mouldboard ploughing by cutting the previous crop low, about beer-can height.
“One of the errors I made in the first year was leaving a lot of taller crop residue across the paddock, but it’s difficult to invert something that is 45 centimetres tall. It tends to poke back through and bring a few weeds back up with it, so residue management is important,” Tony says.
“Seven years on and the paddock we first ploughed is still performing better than I imagined, even with all the mistakes.”
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