Written by Xavier Duff
As seen in ‘The Weekly Times Crop Gear Edition – 22/1/2025’
Many farmers are getting great results from deep ripping as they seek to improve soil problems such as compaction and waterlogging.
The Australian distributor of US tillage equipment manufacturer Unverferth is reporting excellent results from farmers using the company’s Zone-Builder subsoiler to break hard pans, which restrict the root growth into the subsoil necessary for optimum nutrient and water uptake.
“Customers who have bought them have had really good results,” said Mitch Blackmore, sales manager at Oz AG Machinery.
“The secret to effective deep ripping is a machine that cracks or shatters the hard pans in the sub soil to open it up but without disturbing the top layer or mixing layers in the soil profile.
“The Zone-Builder does this job very effectively up to depths of 600mm.
“It has a twofold effect – allowing roots to penetrate compacted layers or clay and access the moisture further down and secondly to encourage water infiltration deeper into the soil profile and allowing the roots to grow deeper.
“We’ve had farmers in South Australia that have had really good results in sand over clay and farmers in pure clay in irrigation country along the Murray, where those soils pack down really hard and tend to shed water rather than absorb it.
“For example last year we had a client who ripped a paddock before some significant rain in January.
“The response was dramatic as that moisture had penetrated much deeper into the soil profile and was stored there.”
In 2024, Mr Blackmore said they dug pits to assess the differences in root establishment and growth in long season canola with a central Victorian farmer who owns a Zone-Builder. Half the paddock was ripped and the other left as is. The difference in root growth was clear to see with much longer roots in the ripped section, Mr Blackmore said.
“We are also seeing improvement in soils prone to waterlogging that are ripped – again, allowing moisture to penetrate down the profile rather than sit on the surface.
“It’s like having a bucket underneath your top soil as against an oven tray – it’s able to allow more moisture to travel down the profile so it doesn’t sit on the surface,” he said.
The foundation of the Zone-Builder is a heavy duty single, three quarter inch (19mm) special-alloy, steep-sloped inch shank, which does the hard work of shattering or cracking the hard layers at depth without disturbing the layers above it.
Front-mounted swivel coulters cut through the crop residues and topsoil with 7000kg of down pressure and allow clean entry of the shank.
Farmers can choose any number of shanks, from four to 10, on a Zone-Builder, with recommended pulling requirements of 30-50 horsepower per shank depending on soil type.
The shanks are fitted with heat-treated, cast invertible wearbars and cast points for extra durability and are protected from hitting rock or other obstacles with either an auto reset trip mechanism for lighter soils or a spring cushion which has high resistance to pressure for tight soils.
There is a model available that uses shear bolts to protect the shank but generally most farmers prefer the auto reset or spring reset models, Mr Blackmore said.
The Zone-Builder is attached to the tractor by three point linkage or it can be attached by the drawbar using an optional caddy. Depth of ripping is adjusted via the linkage on the tractor
or via stabiliser wheels and the caddy and a turnbuckle on the arm assembly.
“The Zone-Builder goes down to a maximum of 600mm but people mostly rip to a depth of between 400-450mm,” Mr Blackmore said.
An optional harrow basket kit is available which chops and evenly distributes crop residues for faster break down and more even emergence.
Prices for the Zone Builder start at $36,000 for the 132 model with auto reset and four shanks and $49,000 for the 122 model with heavy duty spring reset with five shanks.