Summary
Duplex clays at Yering Station restrict roots to the top 30 to 40 centimetres, waterlog in winter, and set hard in summer. A multi-season evaluation showed that FUTURE SOIL CLAY BREAKER reduced soil strength through the clay boundary and enabled near-vertical roots down to about one metre. That structural success also exposed a second constraint. At depth the subsoil was acidic with more sodium and aluminium, so vines that accessed deeper water later in the season showed marginal burn, inter-veinal chlorosis, and earlier senescence. The lesson is simple. Unlock depth with CLAY BREAKER, then manage the chemistry you reveal.
Site and problem
Location Yering Station, Yarra Valley, near Yarra Glen
Soil Fertile topsoil 30 to 40 centimetres over a massive, dispersive clay subsoil
Constraints Winter waterlogging, summer hardness, hydrophobic tendencies, high magnesium, shallow root architecture, poor vertical infiltration, failed cover crops following autumn rain
Trial overview
Blocks M03 primary trial; M06 replicated Monash study
Crop Shiraz
Application Fertigated via drip with pre-flush and post-flush
Monitoring Penetrometer profiles, EM38 conductivity mapping, moisture probes, pits to one metre, visual canopy checks, tissue sampling
Note on rates
Historic work reported mass per hectare. Follow the current FUTURE SOIL CLAY BREAKER Product Data Sheet for modern millilitre per square metre programmes.
What changed in the soil
Soil strength fell at the horizon boundary
Penetrometer data showed the largest decrease in resistance between about 32 and 47 centimetres, where topsoil meets the clay B horizon. Under-vine soil was noticeably easier to penetrate even during dry periods.
Why it matters That boundary controls vertical architecture. Reduce mechanical resistance there and roots can reorganise.
Roots became deep and linear
Profile pits found young structural roots to roughly one metre in treated zones, typically linear and near-vertical through previously massive clay. Control pits did not show this pattern.
Why it matters Deeper structure increases the volume of soil a vine can draw from during deficit periods and is the basis for resilience.
Dispersion improved at depth
At 40 to 60 centimetres treated clods were less dispersive and broke into smaller units. This is consistent with better pore continuity and a lower tension pathway for roots and water.
Bulk wetting pattern looked similar in sensors
Moisture probes tracked similar trends between rows, including after a large December rainfall. That is common. Structural change is often detected first by penetrometer and pits before coarse moisture trends diverge.
What changed in the vines
Late-season stress appeared in some treated rows
From veraison onward, treated vines in one zone and in the Monash rows showed marginal burn and inter-veinal chlorosis, with earlier senescence after harvest.
Subsoil chemistry explains the paradox
Below about 60 centimetres the subsoil pH was below 4.8 with higher aluminium and sodium. Late-season tissue snapshots showed higher chloride and sodium in treated vines than in controls. As CLAY BREAKER enabled depth, vines tapped deeper water that carried more salts and mobilised metals. Structure had improved, but the deeper water source carried a cost.
Key point A depth unlock is only half the job. You must also manage the chemistry you expose.
Practical programme design for duplex clays
1. Diagnose the profile before you start
Pits to at least 80 to 100 centimetres under and between emitters
Soil by depth pH, exchangeable aluminium and sodium, calcium, magnesium, texture and EC
Mapping EM38 or equivalent to flag conductivity patterns and guide pit placement
2. Unlock structure with CLAY BREAKER
Apply under-vine per the current PDS
On sites with acidic or sodic subsoils, use staged first-season passes so vines adapt as depth opens and management can be adjusted
3. Condition the subsoil environment
Low pH at depth Plan a lime programme to lift pH into the workable range for root function and phosphorus availability
Elevated sodium Integrate a calcium source to improve flocculation and displace sodium for leaching when water is available
Topsoil buffer Use FUTURE SOIL LIQUID BIOCHAR in the top 30 to 40 centimetres to increase CEC and moisture storage while deeper layers are being corrected
4. Irrigation once depth is unlocked
Space irrigations to avoid preferentially pulling from the saltiest pools late season
Use leaching pulses only with adequate quality water and a safe drainage exit
5. Nutrition timing
Keep phosphorus and calcium available from fruit set through early berry growth to support new root tips
Avoid late heavy salt loads via fertigation into deficit conditions
Monitoring protocol that fits the growth cycle
Pre-season
Pits and profile sampling to 80 to 100 centimetres
Baseline penetrometer transects under emitters and mid-row
Spring
Penetrometer repeats in November to December at peak root growth when tension data are most informative
Tissue at flowering
Veraison to late summer
Tissue for sodium and chloride plus key cations
If symptoms appear, check subsoil pH and EC at depth
Harvest window
Fruit panel by treatment group Brix, pH, titratable acidity
Optional sodium in juice to quantify exposure risk
Every two years
Repeat pits in the same georeferenced points to document root architecture
Biannual soil test series to track chemical trends
FAQ’s
If CLAY BREAKER opens depth, why did some vines look worse late season
Because depth gave access to more water, but in this site the deeper water carried salts and aluminium. The structure problem was solved, but a chemistry limit surfaced. The answer is not less depth. The answer is pairing depth with pH correction, calcium management, and careful irrigation pulls.
Do I still get value if my probes do not show a big difference
Yes. Structural change is best tracked by penetrometer profiles and pits. Probes often lag or average out local structural effects.
Can I apply CLAY BREAKER and calcium together
Yes. They solve different parts of the problem. CLAY BREAKER reduces tension and improves pore connectivity. Calcium addresses dispersion and sodium on exchange sites. Use each where indicated by profile data.
Grower checklist
Map, pit, and sample by depth before you start
Apply FUTURE SOIL CLAY BREAKER under-vine per PDS, staged where deep acidity or sodium is suspected
Plan lime and calcium based on profile data
Add FUTURE SOIL LIQUID BIOCHAR to lift topsoil CEC and moisture storage
Irrigate to avoid late-season salt draw
Test tissue at flowering and veraison
Penetrometer in November to December, not only at field capacity
Repeat pits every two years and track fruit panels at harvest
Bottom line
On heavy, dispersive duplex clays, FUTURE SOIL CLAY BREAKER can reorganise the root system vertically by lowering soil strength through the clay boundary. That win exposes the real nature of the subsoil. If it is acidic or sodic at depth you must pair structure with chemistry and water management. Do the two together and you keep the depth advantage without paying the late-season salt penalty.