The Soil Test Report reader takes a laboratory soil report and turns it into a fertiliser plan: what the numbers mean, what the crop you intend to grow actually needs, and what to apply to close the gap.
A soil report is one of the few pieces of genuinely valuable, genuinely paid-for information a smallholder gets, and most of it is wasted. It arrives as a sheet of values with recommended ranges beside them and no instruction, in a format written for an agronomist.
This reads it for the crop you name, so the answer is a plan rather than an interpretation — quantities, for your area, of the products actually available, rather than nutrient requirements in kilograms per hectare that still need a second calculation.
It carries its limits plainly: it interprets a report, it does not replace the laboratory, and a wrong number typed in gives a wrong plan out. It says which values it used, so the plan can be checked against the sheet.
It produces a real file — a report a farmer can take to a dealer, a lender or an extension officer, which is usually the point at which a plan has to survive somebody else reading it.
It pairs with Soil Health Tracking, which keeps the same numbers across seasons so the effect of following the plan is visible next year.
How to use Soil Test Interpreter
What it is. An interpreter for a soil laboratory report. Upload the photo or PDF the lab gave you, or type the readings in, and it classifies each one against published standards — USDA/NRCS for pH, the USSL salinity scale for electrical conductivity, the Soil Health Card rating scale for nitrogen, phosphorus, potassium and organic carbon, and published critical limits for the micronutrients — then says what to do about it and which crops suit the result.
When to open it. The day the lab report arrives, and again before you decide what fertiliser to buy for the season. A soil test read six weeks after it was issued has already cost you the decision it was for.
Have ready.
The laboratory report — a photograph of the paper is enough.
Or the readings themselves: pH, electrical conductivity in dS/m, organic carbon %, nitrogen, phosphorus and potassium in kg/ha, and any micronutrients in ppm.
Optionally the crop you are planning, the location, the texture class and the soil colour, all of which sharpen the recommendations.
Step by step.
Upload the lab document, or press 'Enter values' and type the readings in by hand.
Check what was read off the document against what the paper says. A misread decimal point on pH changes every recommendation below it.
Add the crop you are planning. The suitability section is only meaningful once it knows what you intend to grow.
Press Generate Report and read the classification for each reading, the concerns, and the recommended actions.
Download the PDF. This is the document to show an agronomist, a lender, or a buyer asking about the ground.
What it will not do. It interprets the numbers you give it against published standards. It does not test soil, cannot know how the sample was taken, and does not know your local recommendations, your variety or your yield target. It states no fertiliser dose — the quantity to apply depends on crop, target yield and local extension recommendations, and a figure produced without those would be a guess wearing a lab coat.
Every setting in Soil Test Interpreter, explained
Soil pH
How acidic or alkaline the soil is. It decides how available every other nutrient is, whatever the test says is present. How to choose: Enter it exactly as the lab gives it, to one decimal place. The agronomic optimum for most crops is 5.5 to 7.5, and maize and wheat prefer a narrower 6.0 to 6.5. If it is wrong: Everything else is misread. A phosphorus figure that looks adequate at pH 8.5 is largely locked up and unavailable, and the report can only tell you that if the pH is right.
Electrical Conductivity (dS/m)
Salinity. High salinity stops roots drawing water up even from soil that looks wet, and is directly toxic to salt-sensitive crops. How to choose: In deciSiemens per metre, as the lab reports it. Below 2 is non-saline; 2 to 4 restricts very sensitive crops; 4 to 8 restricts many crops; 8 to 16 leaves only salt-tolerant crops; above 16 only very tolerant ones. If it is wrong: Salinity is the reading most likely to explain a field that fails no matter what fertiliser goes on it, so getting it wrong hides the real problem.
Organic Carbon (%)
The carbon fraction of soil organic matter — the single best proxy for what people mean by soil health. How to choose: As reported. Under 0.5% is low, 0.5 to 0.75% is medium, above 0.75% is high. If it is wrong: The report also derives organic matter from this, multiplying by 1.724 on the standard convention that organic matter is about 58% carbon. An error here carries into both figures.
Nitrogen (kg/ha)
Available nitrogen, the nutrient that most often limits yield and the one that leaves the soil fastest. How to choose: As reported. Below 280 kg/ha is low, 280 to 560 is medium, above 560 is high, on the Soil Health Card rating scale. If it is wrong: Nitrogen is mobile and needs regular replacement, so an overstated figure directly under-fertilises the crop.
Phosphorus (kg/ha)
Available phosphorus, which drives root development and early establishment. How to choose: As reported. Below 10 kg/ha is low, 10 to 25 is medium, above 25 is high. If it is wrong: Phosphorus is much less mobile than nitrogen, so an error here persists for seasons rather than weeks.
Potassium (kg/ha)
Available potassium, which governs water regulation and standing ability. How to choose: As reported. Below 108 kg/ha is low, 108 to 280 is medium, above 280 is high. If it is wrong: A low potassium soil fertilised only with nitrogen produces tall, weak growth that lodges.
The micronutrients. Each is compared against its published critical limit, below which a deficiency response is likely. How to choose: Enter them in the units the lab used — zinc, iron, manganese and copper are DTPA-extractable ppm. The critical limits applied are zinc 0.8, iron 4.5, manganese 1.0 and copper 0.2 ppm. If it is wrong: Boron and sulphur are deliberately not given a critical limit, because no single figure is reliable across soils. The report says so rather than inventing one.
The physical properties, which decide how the soil behaves rather than what it contains. How to choose: Optional, and worth filling in. Texture in particular changes how the nutrient figures should be acted on, because a sandy soil loses nitrogen far faster than a clay. If it is wrong: Nothing is miscalculated; the recommendations are simply more general than they needed to be.
Zinc 0.5 ppm: below the 0.8 ppm critical limit, so a zinc response is likely.
The useful reading here is not any single low figure — it is that a moderately alkaline soil with low organic carbon and low zinc is a recognisable pattern, and that applying more phosphorus without addressing the pH will mostly feed the soil rather than the crop.
How to read what it gives you
Every classification band on the report is a published standard with its source named. None of them is Laisha's opinion.
A reading you did not supply stays visibly blank. The report does not fill a gap with a plausible number — it shows you the gap, which is the only honest way to hand somebody a document they will make a decision on.
Low, medium and high are relative to a general agronomic scale, not to your crop's requirement. A 'medium' potassium soil can still be short for a heavy potassium feeder.
The 'Other Readings on Your Document' section holds anything the lab reported that Laisha does not classify. It is shown rather than dropped, because your lab may test things this does not.
What usually goes wrong
Acting on nutrient figures while ignoring pH. At pH 8.5 or 5.0 the availability of what is there matters more than the quantity.
Comparing a reading against a band from a different extraction method. Nitrogen, phosphorus and potassium bands here are for the kg/ha values the Soil Health Card scale uses; a lab reporting in ppm by a different extractant is not on the same scale.
Testing one spot and treating it as the whole field. Soil varies across a field far more than most people expect; a composite sample from several points is the standard for a reason.
Sampling straight after fertiliser has gone on. The result describes the fertiliser, not the soil.
Questions people ask about Soil Test Interpreter
What does my soil pH actually mean?
It sets how available the nutrients are. Most crops do best between 5.5 and 7.5, and maize and wheat prefer 6.0 to 6.5. Outside that range, nutrients that are present in the soil are chemically locked and the plant cannot reach them — which is why a high phosphorus reading on an alkaline soil often produces a crop that behaves as though phosphorus were short.
Is my nitrogen level low or high?
On the Soil Health Card rating scale, available nitrogen below 280 kg/ha is low, 280 to 560 is medium, and above 560 is high. Most intensively cropped soils test low, because nitrogen is mobile and leaves with water.
What EC value means my soil is saline?
Below 2 dS/m is non-saline. Between 2 and 4 only very salt-sensitive crops are restricted; 4 to 8 restricts many crops; 8 to 16 leaves only salt-tolerant crops viable; above 16, only very tolerant ones. That scale is the USSL classification from 1954, still cited by FAO.
How do I convert organic carbon to organic matter?
Multiply by 1.724, on the standard convention that organic matter is about 58% carbon. It is an approximation rather than an exact conversion for every soil, and the report derives it for you.
Will it tell me how much fertiliser to apply?
No, and that is deliberate. A dose depends on the crop, the target yield, the variety and your local extension recommendation, none of which a soil report knows. It tells you what is low and what is locked up; the quantity is a conversation with somebody who knows your district.
Can I just photograph the lab report?
Yes. Upload the photo or the PDF and the readings are pulled off it. Check them against the paper before generating — a decimal point read wrongly on pH changes every recommendation underneath it.
Why are boron and sulphur not given a low or high rating?
Because no single critical limit for them is reliable across soil types, and inventing one would make the report less trustworthy rather than more complete. They are shown with an explanation instead.