Buntine grower Michael Dodd has one of the longest track records of deep-ripping in WA.
PHOTO: Evan Collis
Subsoil compaction is a major issue for grower Michael Dodd, but deep-ripping and controlled-traffic farming (CTF) are helping to overcome the impact on crop yields, particularly in years when annual rainfall falls short of the 320-millimetre average at his Buntine, Western Australia, farm.
Michael says a hardpan has developed in his sandy soils at a depth of between 250mm and 500mm because of machinery and livestock traffic.
He started deep-ripping in the 1980s when a local dealer set up a trial on his property to investigate the yield impacts of deep-ripping to a depth of 152mm, 228mm and 305mm. The trial showed no change in yield at 152mm, a slight change in yield at 228mm and a significant yield increase at 305mm.
The trial and Michael’s experiences over the years have shown that wheat grown in the first year after deep-ripping can yield between 0.5 tonnes per hectare and 1.0t/ha more than wheat grown on unripped land.
He has also discovered yellow sandplain country that has been deep-ripped generally does not need to be ripped again for another five years, although the time between treatments is sometimes longer because seasonal conditions may not be conducive to deep-ripping
Season 2015, however, was perfect for deep-ripping. Large falls of rain during harvest enabled Michael to rip 1200ha of the 5300ha he has under crop, providing an excellent opportunity to boost yield.
To complete the task, he used a 373-kilowatt tractor and a nine-metre-wide ripper set on 457mm tyne spacings, followed by a set of 32mm coil packers.
The implement ripped the soil to a depth of 300mm, working at between five and eight kilometres an hour.
To preserve the deep ripping investment, Michael sold all his sheep three years ago and started implementing CTF two years ago.
Although not all the machinery runs along the same wheel tracks, he is working towards that goal as machinery is replaced and hopes CTF will extend the period of de-compaction from five years to eight years.
Since implementing CTF, Michael has noticed wheat plants in the trafficked zone are smaller and more stressed than plants growing on the deep-ripped and untrafficked country.
Going forward, Michael is taking a keen interest in the work of neighbouring growers who have added topsoil inclusion plates onto their deep-ripping tynes to ameliorate their acidic subsoils.
He hopes to add topsoil inclusion plates to his own deep-ripper next year to move lime-treated soil from the surface (pH 5.5 in calcium chloride) into his acidic subsoils (pH 4.5 in calcium chloride).
He also plans to research the optimum angle across the paddock for deep-ripping to ensure seeding depth is not compromised.
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