When and How Do I Start Using the Yeomans Keyline Plow?

Start immediately — as soon as the plow is delivered.

Do not wait for rain to soften the soil, as is common practice with conventional cultivation. The purpose of Keyline cultivation is to ensure that the next rains are absorbed and stored in the soil, not lost as runoff.

The only exceptions are on grazing land where no rainfall is expected for many months and extremely dry hard soil which may fracture poorly; in these conditions, wait until soil has some moisture, but do not wait for it to become wet.

What if the soil is very wet?

After heavy or prolonged rain, soils are often waterlogged and short of air. The fungi and bacteria responsible for creating humus are aerobic — they breathe oxygen. In saturated soils, soil life is effectively drowning.

As soon as you can safely get a tractor onto the paddock, use the Yeomans Plow to restore air pathways. With air reintroduced, soil life responds rapidly and biological activity accelerates dramatically.

Getting Started — general setup for soil rejuvenation

If you are beginning without a specific cultivation objective:

  • Set shank spacing at around 500 mm (20”)

Depth Selection

  • Virgin country: start at about 200 mm (8”), or slightly deeper
  • Previously cultivated land: dig down with a shovel to find the old hardpan, then set the plow 50–75 mm (2–3”) below the hardpan

Start plowing at this depth.

If the ground pulls too hard

On the first pass through very compacted soil, draft loads can be high. If pulling becomes difficult:

  • Do not reduce depth
  • Simply remove a shear pin and lift one or two shanks out of the ground

This takes less than thirty seconds and immediately reduces draft. On the next cultivation, the soil will pull far more easily and the shanks can be dropped back in just as quickly.

What Correct Operation Looks Like

The plow is working perfectly when:

  • the soil lifts gently around the shank
  • then settles back, but not quite to its original position

If hardpan lifts out in large slabs like broken concrete, fit a crumble roller to cut and flatten the clods. This greatly speeds the formation of fertile soil.

What Happens Next?

With soil opened to depth:

  • storm rainfall penetrates directly into the worked zone
  • surface runoff and erosion virtually disappear
  • air and moisture occupy the soil profile together

Provided there is dead root material for microbes and fungi to feed on, soil biological activity explodes, and fertility is created at a speed rarely seen in agriculture.

How Deep Should I Plow?

Where no hardpan exists

  • First cultivation: 75–100 mm (3–4”) deeper than the main root mass
    (typically 150–250 mm / 6–10”)
  • Subsequent cultivations: about 50 mm (2”) deeper than the previous pass
This progression generally provides full fracture between shanks and encourages roots to follow the loosened zone downward.
There is usually no commercial advantage in cultivating much deeper than 350 mm (14”), except in badly leached soils where deeper mineral access is required.

 

Where a hardpan is present

The theoretical ideal is to cultivate halfway through the hardpan, but this is rarely practical.
Instead:
  • In moist conditions, cultivate just under the hardpan with all shanks engaged
  • In drier conditions, remove every second shank and space them as far apart as possible front‑to‑rear, then cultivate a few inches below the pan
Even without rain, the pan will begin to break down. At the next cultivation, repeat at a similar depth. Future depth should always be governed by the deepening root zone, not by machinery alone.
A crumble roller is an excellent alternative where large slabs form, as it speeds soil breakdown and biological access.

Irrigation Country

On flood‑irrigated land, cultivate shallow at first. Excessively deep initial work can cause water loss below the intended root zone.

How Fast Should I Travel?

A good rule is walking pace:

  • 5–6 km/h (3–4 mph)
Higher speeds are possible, but slower travel:
  • allows the soil to lift and settle gently
  • minimises mixing of soil layers
  • protects soil microbiological life
In deep subsoiling, you are working ground that may never have been disturbed before. Slower speed gives time to react to hidden obstructions and reduces shear pin failures, especially with smaller tractors.

Direction of Travel

When using a Yeomans Plow for soil improvement, direction of travel matters because it determines how water moves once the soil has been fractured.

General rule: Cultivate approximately at right angles (90°) to the direction water naturally flows downhill. In most paddocks, this means working across the slope, not straight up and down it.

The Yeomans Plow creates long, continuous fracture lines in the soil. These fractures become preferred pathways for air, roots, and water once rain occurs. The plow’s purpose is to increase infiltration and storage, not to move water downhill.
If you cultivate up and down the slope:
  • fracture lines align with gravity
  • water is encouraged to move downhill rapidly
  • runoff and erosion risk increases
  • water concentrates instead of spreading
If you cultivate across the slope:
  • fracture lines interrupt downhill water flow
  • rainfall slows, spreads sideways, and soaks in
  • water is absorbed into the worked soil profile
  • erosion is reduced and soil moisture is retained

Should I Overlap the Passes?

Yes, a Yeomans Keyline Plow does not cultivate the soil in neat vertical slots directly under each shank. Each shank creates a wedge‑shaped fracture zone that spreads outward and upward from the point as the soil lifts and then settles back.

For Keyline cultivation to work properly, these fracture zones need to meet and overlap, so the entire soil profile is opened — not just isolated strips. If passes are spaced too far apart, you end up with:
  • fully fractured soil under the shanks
  • untouched ribs of compacted soil left between passes
These unbroken ribs restrict root movement and water flow, even though the surface may look worked.

When overlap is correct:

  • soil lifts gently and settles back across the entire worked width
  • roots can move laterally and vertically without hitting compacted walls
  • water infiltrates evenly, rather than channelling down narrow slots
When overlap is insufficient:
  • roots “stall” between passes
  • water movement becomes uneven
  • benefits are slower and less reliable

When During the Year Should I Use the Plow — and How Often?

A second cultivation is usually beneficial about one month after the first significant rains. This allows hardpans time to weaken and fracture naturally between passes.

For pasture:
  • Cultivate at least once per year to begin with
  • In the first year, two passes may be beneficial
  • Ideally cultivate before the rainy season and hot weather
Do not cultivate immediately after grazing a paddock bare. Allow grasses several weeks to re‑establish so sufficient root mass and residue are present to support soil biology.

Do I need a Crumble Roller?

A crumble roller is used when you want to finish the job in one pass—leaving the soil level, stable and protected immediately after Keyline plowing, rather than loose or ridged.

Yeomans plows are designed to fracture the subsoil without turning it over, but depending on soil type, moisture and surface cover, the plowing action can leave raised lines or loosened surface material. A crumble roller gently reconsolidates the surface, pressing fractured soil back into contact without destroying the subsoil fissures created by the plow.

You are most likely to need a crumble roller when:

  • You are working light, sandy or friable soils
    In lighter soils, subsoiling can lift and fluff the surface excessively. A crumble roller firms the soil just enough to prevent wind erosion and moisture loss while keeping the soil profile open below.
  • You are renovating pasture and want a clean finish
    After pasture renovation, a crumble roller leaves a smooth, stock‑safe surface that can be grazed or oversown sooner, without ridges or loose clods that interfere with seed‑to‑soil contact.
  • You want to retain surface moisture
    Loose soil dries quickly. By lightly consolidating the surface, a crumble roller helps seal moisture in, complementing the Yeomans plow’s role in improving infiltration and subsoil water storage.
  • You are preparing ground for follow‑up operations
    Where spraying, mowing, sowing or harvesting equipment will follow, the crumble roller produces a level, traffic‑ready finish, reducing the need for additional passes.
  • You are aiming for maximum biological benefit
    Keyline plowing is about stimulating soil biology through aeration and moisture movement. The crumble roller supports this by maintaining soil structure, avoiding excessive disturbance at the surface while allowing air, water and roots to move freely below.

Do I Need Coulters?

Coulters are used to cut and part surface material ahead of the shank, allowing the Yeomans plow to pass through cleanly while minimising tearing, dragging or surface disturbance. Coulters do not affect the subsoiling action below the surface.

Coulters are often useful in:

  • shallow, densely matted pasture
  • vine‑type groundcovers that tend to bunch
After several cultivations, roots tend to grow downward rather than sideways, reducing the need for coulters.
Coulters have little effect on subsoiling itself. Avoid them in very rocky ground, where they can be overloaded. On large trailing plows, a small number of strategically placed coulters can prevent residue buildup during long runs.

 

What Happens When You Hit a Stump or Rock?

Yeomans plows and shanks are built for deep, first‑time subsoiling in difficult country.

  • Most roots and smaller stumps are pulled through or broken
  • Large stumps may shear a pin, allowing the shank to swing back safely
  • Replace the pin at the end of the run and continue
Often, after roots are severed, the main stump lifts easily on the next cultivation — making this one of the cheapest and simplest ways to clear land.
Large rocks (up to around half a tonne) are often pulled free. Bedrock is scraped over. Shear pins protect the plow when required.

Stump Jump Shanks should be used when cultivating ground that contains hidden or unavoidable obstructions, such as rocks, stumps, buried timber, heavy roots, or uneven subsurface conditions. They are specifically designed for first‑pass subsoiling in country that has never been cultivated, or has been declared “uncultivatable” by conventional equipment.

Weeding

Yeomans offer a number of different solutions for controlling weeds:

Weed Knives
The weed knife is a light, shallow‑working tool designed for effective weed control with minimal soil disturbance, particularly in already worked or relatively stone‑free ground. Mounted to the Yeomans shank system, the knife slices cleanly through small weeds just below the soil surface, severing roots while leaving the soil profile largely intact.

Wobble Blade
Wobble Blades are a patented Yeomans design for weeding and cultivation in rocky or stump‑ridden ground.
Unlike rigid weed knives:
  • the blade assembly pivots sideways on a heavy duty pin
  • when an obstacle is hit, one blade swings back while the other advances
  • a central vertical fin keeps the system tracking straight
This design allows confident cultivation in unknown or rough ground, including scrub country, where small bushes are treated like weeds.

Batswings are heavy‑duty sweeps used for:

  • weed control
  • shallow cultivation where sweeps are appropriate
They can be inverted for hilling up in row crops, last roughly twice as long as conventional sweeps, and can be hard‑faced for extra wear. They are also used successfully in sugarcane for deep working where soil conditions allow.

 

Can I Fit Conventional Chisel Plow Points?

Yes.

Using the AJ50 adaptor, Yeomans shanks can accept standard chisel plow points and sweeps with Graeme Hoeme bolt centres. This gives access to hundreds of earth‑working options and allows the Yeomans to function as a highly versatile, all‑purpose cultivating tool.