The Method
From Soil Sample to Spray Tank: How the Succession Soils Method Works
Three tools. One decision chain. Biology and physics before chemistry.
Most fertiliser decisions are made on a soil test alone. A soil test tells you what is sitting in the soil. It does not tell you what the tree is actually eating, and it does not tell you whether the tree can even use what it holds. That gap is where money gets wasted and yield gets lost.
The Succession Soils Method closes the gap with three tools used in order — from a free field score you can run yourself, to the engine that turns lab numbers into a spray tank. This page walks the whole chain on one real orchard block, so you can see exactly how it works before you start.
The Three Tools
You climb these in order
Each one answers the question the last one raised.
Soil Health Assessor — free, run it yourself
A field score of your living soil in about 30 to 45 minutes. Nine indicators you can see and measure in the field — bare earth, infiltration, compaction, aggregate stability, earthworms, rooting depth, soil smell, and more. No lab. Run it three times a year — pre-flowering, mid-season, and post-harvest — so you are tracking a trend, not a snapshot. This is your starting point and it costs nothing.
Open accessFull Soil Health & Biodiversity Assessment — by request
The deeper version. It keeps the nine field indicators and adds seven more, including the biology a field score can only estimate: the fungal-to-bacterial ratio, microbial biomass, and a CO₂ burst test that reads how hard the soil life is actually breathing. Sixteen indicators in total, across four tiers, with gateway logic that catches the problems which override everything else. It can also take your lab numbers — acid saturation and phosphorus — to flag aluminium toxicity and phosphorus problems the eye cannot see.
ProvisionedSAP Analysis Engine — by request
The engine that reads your sap, soil, and leaf results together and produces a spray programme tuned to your block, your crop, and your tank.
ProvisionedThe first tool is open to everyone. The other two are switched on for growers and consultants who are ready to act on what they find — a short request tells us your crop, block size, and region, and we set you up.
The Principle Behind All Of It
Biology and physics override chemistry.
Here is the rule the whole Method runs on. A tree cannot use a nutrient the soil will not release, and it cannot build with a nutrient it cannot move to where it is needed. If the soil is compacted, bare, or biologically dead, good chemistry stays locked away no matter how it looks on paper.
So when the soil score comes back critical, the engine does something most fertiliser programmes never do: it stops the soil-applied inputs that are making things worse and feeds the tree through the leaf instead, while you rebuild the soil underneath. You do not throw good product at ground that cannot use it.
Watch this rule decide the whole programme on Block 12B.
The Worked Example
Block 12B, step by step
A commercial macadamia block on the KwaZulu-Natal North Coast. Sandy loam, 4.8 hectares. On paper — on the soil test — it looked workable. Even the sap calcium came back fine. The tree was still in trouble. Here is what the three tools found, step by step.
Score the soil
Free field scoreMeasure biology
16-indicator assessmentTest the sap
Sap, soil & leaf + conditionsDiagnose
SAP engine ranks itStop & spray
Stop list + foliar tanksRebuild
Fix the soil, resampleScore the living soil, free
Tool: Soil Health Assessor (free, 9 indicators)
What you do
Walk the block and score nine field indicators — bare earth, infiltration, compaction, aggregate stability, earthworms, rooting depth, soil smell, and more. The tool adds them up out of 100 and flags anything critical. It takes 30 to 45 minutes, and you run it three times a year: pre-flowering, mid-season, and post-harvest.
Why it matters
Some problems override everything else. Bare earth, a hardpan, or salinity will shut down nutrient uptake no matter how healthy the rest of the picture looks. The free score uses "gateway" indicators to catch those first — if one fails, it caps the whole score, because fixing it comes before anything else. This is the doorway: it costs nothing and it tells you whether you need to look deeper.
What 12B showed
The free field score flagged trouble straight away — visible bare earth and a hard compaction layer underfoot. Enough to say: this block needs the full assessment, not a fertiliser order.
(Record temperature, humidity, and soil moisture while you score — they matter for what comes next.)
Measure the biology
Tool: Full Soil Health & Biodiversity Assessment (gated, 16 indicators)
What you do
Run the full assessment. It keeps the nine field indicators and adds the measured biology — the fungal-to-bacterial ratio, microbial biomass, and a CO₂ burst test that reads active microbial respiration — for sixteen indicators scored across four tiers out of 100. A failed gateway from the field score carries its penalty straight through.
Why it matters
The free score tells you whether the soil is struggling. The full assessment tells you why, by measuring the living part of the soil instead of estimating it. That measured biology is what decides whether the ground can deliver and cycle nutrients on its own, or needs rebuilding first.
What 12B showed
6.04 out of 100. A gateway penalty of −77% fired immediately, triggered by two things: 30% bare earth and a penetrometer reading of 350 — a hard compaction layer. The measured biology confirmed the diagnosis: fungal maturation scored 7.8 out of 65, active biology 16.5 out of 30. This soil was physically and biologically shut down. That verdict is what forced the whole programme foliar-first later on — you cannot fix a tree through the roots of a soil in this state.
(12B was assessed on the then-current 15-indicator version; the CO₂ burst test has since been added as the 16th.)
Test what the tree is eating
Tool: sap analysis (plus soil and leaf for triangulation)
What you do
Send new-growth and old-growth leaf samples for sap analysis. Add a standard soil test and a leaf tissue test so the engine can cross-check all three. Sample at the critical stages in the tree's year — early flower, fruit or nut set, fill, maturity, and post-harvest — because what the tree needs changes as it moves through the season. And record the temperature, humidity, and soil moisture at the moment of sampling — this is not optional, and the next paragraph explains why.
Why the weather matters — the mobility check
Some nutrients move around inside the tree; some do not. Calcium and boron travel almost entirely in the transpiration stream — the flow of water the tree pulls up from root to leaf. They only reach the new growth when the tree is transpiring. That flow is driven by vapour-pressure deficit (a product of temperature and humidity) and by how much water is in the soil.
So a reading has to be judged against the conditions it was taken in. If the block was sampled under conditions that support transpiration — a working vapour-pressure deficit and adequate soil moisture — the reading reflects true nutrient status. If the conditions were against it — dry soil, or air too still to move water — that does not cancel the reading; it becomes part of the diagnosis, and it points at the water and the soil as much as the chemistry. That is why we log the weather and the soil moisture at both the assessment and the sap sampling: it is what turns a reading into a diagnosis.
What 12B showed
This is where a soil test would have sent you the wrong way. The soil calcium read "adequate", and the sap calcium read 830 ppm — optimum. Nothing wrong with the calcium. And yet the tree was failing, for three reasons a soil test never sees:
- Nitrogen it could not turn into protein. Ammonium sat at 74.7 ppm (excess) while nitrate was 4.4 ppm (critically low) and molybdenum was near zero (critically low). Molybdenum runs the enzyme that lets a tree build protein from nitrogen — and sap pH at 4.6 was locking that molybdenum away. So the tree held plenty of nitrogen but could not use it. Worse, the leftover free amino acids and loose ammonium act as a "dinner bell" for sucking pests — thrips, lace bugs, aphids.
- Calcium it could not steer. Calcium was optimum, but calcium is immobile — it cannot walk from old leaves to new growth on its own. Boron is the steering wheel that directs it, and boron was critically low at 6.4 ppm. Silicon, the third leg of the structural triad, was short too. With boron and silicon down, the tree cannot build strong cell walls even with plenty of calcium on hand — which leaves it open to heat stress, pathogens, and poor nut set.
- Potassium crowding the rest out. Potassium was running high at 5 456 ppm, displacing other cations at the root.
What a soil test sees
What the sap + engine see
Conditions at sampling
23 °C, 58% humidity, and soil moisture very dry at under 20% of field capacity. This is where the conditions earn their place. The air was primed to transpire — that pairing gives a vapour-pressure deficit of about 1.2 kPa, a healthy pull. But the soil was far too dry to supply the water, so the tree would have closed down to protect itself and the transpiration stream slowed to a crawl. Calcium and boron both ride that stream, so on a block this dry, even the corrections that are needed will not travel to new growth through the roots. The dry soil does not change the diagnosis — it confirms the treatment has to go on through the leaf.
Run the SAP Analysis Engine
Tool: SAP Analysis Engine (by request)
What you do
Upload the sap results, add the soil and leaf tests, and set your crop, growth stage, tank size, spray area, and the field conditions at sampling. The engine triangulates all three data sources and ranks every finding as Urgent, Watch, or Good.
Why it matters
Triangulation stops you acting on a single reading — a flag confirmed by two tests ("Verified") carries more weight than one seen in sap alone ("Sap Only"). The engine also takes the temperature, humidity, and soil moisture you recorded and uses them to weigh whether a low reading is a true shortage or a mobility problem, for every nutrient. And this is where the override rule bites — a critical soil score forces the engine into foliar-first mode automatically.
What 12B showed
Three Urgent diagnoses, each with its mechanism spelled out:
- Ammonium acidification / stalled protein synthesis — excess ammonium acidifying the root zone; nitrate and molybdenum critically low; the tree unable to convert nitrogen to protein.
- Calcium–boron–silicon structural risk — calcium optimum but unsteerable, boron and silicon short, cell-wall building compromised.
- Cation displacement — excess potassium pushing other cations out at the root.
Because the soil score was critical, the engine set the whole programme to foliar-first before writing a single line of treatment.
Read the report: the Stop List
Tool: SAP Analysis Engine report
What you do
Read the engine's output — the ranked diagnoses, the Stop List (what to stop applying now), and the treatment protocol it builds for you.
Why it matters
The Stop List is where the Method saves you money and undoes harm. It names the soil-applied inputs that are actively making things worse — not to punish them, but because feeding a problem while you treat it is throwing money away. Foliar corrections for the blocked nutrients still go ahead; it is the soil-applied forms that stop.
What 12B showed
Two hard stops.
- Stop all soil-applied potassium — every form. It is driving the cation displacement. On this block, more potassium in the ground makes the crowding worse.
- Stop ammonium-based fertilisers — MAP, DAP, UAN, ammonium sulphate. They are feeding the ammonium acidification that has stalled the tree's protein machinery.
Both are soil-and-root antagonisms. The foliar programme carries the tree while these come off.
Mix and spray
Tool: SAP Analysis Engine — Field Sheet
What you do
Follow the day-by-day programme. The engine builds it as tanks, in a set mixing order, with the water rate and pass count worked out so every nutrient lands at the rate the tree needs without the mix burning the leaf.
Why it matters
Getting the right nutrients is only half the job — getting them onto the leaf without doing harm is the other half. Two things wreck a foliar spray. The first is incompatibility: some nutrients cannot share a tank. Put calcium and phosphorus together and they lock up into a solid that never reaches the tree; several trace metals clash the same way. That is why the engine sorts nutrients into separate tanks and prints a "do not add" list for each one. The second is salt loading: every dissolved salt in the tank adds up, and past a safe concentration the spray pulls water back out of the leaf and scorches it — phytotoxicity. The engine totals the salt load, holds it under a safe ceiling, and splits the job into more passes rather than risk the crop.
On top of that, it does not just dump raw salts on the leaf. It carries them in with absorption aids — fulvic acid to chelate the metals and help them cross the leaf surface, fish silage as a carrier and biostimulant, and sorbitol, which complexes with calcium and boron and helps the tree actually move them into new growth. That last one matters here: sorbitol is part of the answer to the "cannot steer calcium" problem from Step 2.
What 12B showed
Two foliar tanks, and notably no potassium or phosphorus tank at all — you do not spray what you are trying to stop.
- Tank 1 — the micronutrients: iron, zinc, copper, and molybdenum, rebalanced to macadamia proportions (zinc 64%, iron 18%, copper 18%), chelated with fulvic acid and held at a target pH of 6.0–6.2. Calcium, phosphorus, boron, and silicon are kept out of this tank — they would clash with the metals.
- Tank 2 — the structural triad: boron (Solubor) and calcium (calcium nitrate), carrying the silicon leg, with sorbitol to help the tree steer the calcium and boron into new growth — rebuilding cell-wall strength.
The salt load was high enough that the engine flagged a tank-mix safety violation (4.49 g/L against a 1 g/L ceiling) and auto-split the job into 8 passes — four of Tank 1, then four of Tank 2 — with the water rate lifted well above the standard 1 300 L/ha to stay under the phytotoxicity limit. The Field Sheet hands your operator the exact rates, the mixing order, and the pass schedule, so none of that has to be worked out in the shed.
Rebuild the soil, then resample
Tool: the Method (and back to the Assessor)
What you do
While the foliar carries the tree, fix what the assessment flagged. On 12B that means covering the 30% bare earth with mulch or a cover crop, breaking the compaction layer, and feeding the biology back — compost, hydrolysate, the on-farm biological programme — so the soil starts cycling nitrogen and holding water again. Then resample the sap at the next critical stage, and re-score the soil at its next window — pre-flowering, mid-season, or post-harvest — under recorded conditions, so the comparison is fair.
Why it matters
Foliar feeding is the bridge, not the destination. The goal is soil that turns its own nitrogen into nitrate, holds water through a dry spell, and lets the roots reach the calcium that is already there. You watch the trajectory — the score climbing, nitrate returning, the potassium easing off. You track it. You do not hope.
Where 12B stands
Diagnosis done, Stop List actioned, foliar programme built, soil rebuild underway. This block is early in its transition. We will add the resample and yield results here as they come in.
Why This Beats A Soil Test Alone
Guessing versus knowing
Run 12B on a soil test by itself and you would have seen adequate calcium, workable numbers, and reached for the usual bag. The tree would have kept failing — because the problems were never about a nutrient being missing. They were about nutrients the tree could not use: nitrogen it could not turn into protein, calcium it could not steer without boron, and potassium crowding the rest out. And the fix was not more product in the ground — three of the worst inputs had to stop, while the corrections went on through the leaf.
The Method caught all of it because it looked at four things at once: the soil (what is there), the sap (what the tree is actually eating and using), the living soil score (whether the ground can deliver), and the conditions at sampling (whether the reading can be trusted). That is the difference between guessing and knowing.
Your Next Step
Start where it costs nothing
Want the detail? Read the SAP Analysis Engine User Manual — every field, every score, explained in plain language.
Growing a specific crop? See how the Method is tuned to macadamia, avocado and citrus soils.
Common Questions
What is SAP analysis and how is it different from a soil test?
A soil test tells you what is in the soil. Plant SAP analysis tells you what the tree has actually taken up and is moving in its leaves right now. We test the sap from old and new leaves, so we can see a problem forming weeks before it shows on the tree or in the fruit. That is why we test the plant, not just the soil.
How long does a regenerative transition take?
Most orchards begin showing measurable improvements within one to two growing seasons, while a resilient, biologically active soil typically develops over three to five years. When the transition is carefully managed, the yield dip often associated with the “J-curve” can usually be minimised or avoided as trees become less dependent on synthetic inputs and soil biology takes over key nutrient cycling functions. Depending on the starting condition of the soil, climate, and management, measurable improvements in soil biological activity are often seen within as little as eight months.
Will my yield drop while I move to regenerative practice?
The honest answer is that yield can dip during the changeover if it is rushed. Our whole method is built to avoid that. We cut inputs in step with the soil's own supply, guided by SAP testing, so the tree is never left short. The goal is steady yield on falling costs, not a gamble.
Which crops do you work with?
We work with macadamia, avocado and citrus growers. Most of our work is in KwaZulu-Natal and Mpumalanga, though the method suits any commercial fruit or nut orchard.
What is the F:B ratio and why does it matter for my orchard?
F:B is the balance of fungi to bacteria in your soil. Young, disturbed soils are bacteria-heavy; healthy orchard soils are fungal dominant. Tree crops like macadamia, avocado and citrus feed best in fungal-dominant soil, where mycorrhizal fungi extend the root system and help the tree draw water and nutrients. Building that fungal side is a big part of what we do.
How do I get started with Succession Soils?
The first step is a soil health assessment, so we can see what your soil is doing before we change anything. From there we build a simple plan and track it with SAP testing through the season. Get in touch to book a first consultation.