The short answer. A soil carbon baseline is the first measurement of the carbon in your fields, taken field by field in the autumn-winter sampling window. Every later round is measured the same way, at the same point in the year, and compared with it, so the baseline is what turns a single result into a record of change. You receive a report of each field’s starting point with the accuracy stated and a map of each field at 10-metre resolution, and the results are yours.
Why the baseline matters
Soil carbon only means something as change. A single result tells you where a field is; a baseline and an annual round tell you which way it is going, and whether your management and that year of weather built soil resilience or cost it. Without a baseline there is nothing to measure change against, which is why the first round is the most important one to get right and to take at the right time.
How the baseline is taken
- Set up. Your SBI number and a short call to agree field boundaries and sampling access.
- Sampling design. Sampling is designed field by field, so every field you are paying to monitor has its own result.
- Sampling on farm. About half a day, in the autumn-winter window when fields are between crops.
- Laboratory and satellite. Samples are analysed by dry combustion in an ISO-accredited laboratory and tied to satellite imagery at 100 readings a hectare.
- Your report. Each field’s starting point, with the accuracy stated, and a 10-metre map of each field.
The only other thing we need is the records you already keep. How each step works is covered in how soil carbon is measured.
Timing: the window you have to hit
Soil carbon has to be sampled at the same point in the year for the change between years to be real, so the baseline sets the window that every later round will use. The 2026 autumn-winter sampling window is open until the end of February 2027. Miss it and your baseline is delayed by a year, with sampling beginning again in autumn 2027. More in why soil carbon is measured once a year.
What happens after the baseline
Each year we sample and analyse again in the same window, timed around your cropping, and report the change against your baseline in tonnes of carbon per hectare, field by field, with the accuracy stated. That annual record is what shows which of your practices are working, catches decline while you can still act, and gives a buyer, a lender or an auditor evidence rather than an assumption. Because every round is measured to full Registry standard, the same record supports emissions reporting or credits later if you choose to add them.
Paying for the baseline
A small deposit secures your place in the sampling season. The balance for the baseline round is invoiced once it is complete, and annual monitoring is invoiced each year on your normal account. The price depends on the size of the holding, the number of fields and the tier you choose, and larger holdings cost materially less per hectare. What sets the price per hectare explains the three things that move it.
Questions we are asked about the baseline
Do I have to baseline my whole farm?
No. Our minimum project area is 150 hectares, and many farms start with the block they are changing or the fields they are least sure about. Fields added later get their own baseline from the round they join. See what 150 hectares means in practice.
Can existing soil sample data be used?
Historic soil sample data that meets our methodology standards can be onboarded to create historic baselines for a project. Ask when you request a quote and we will tell you whether yours qualifies.
What if I miss this sampling window?
Your baseline moves to the next autumn-winter window, which means a year later before you can show anyone which way your soil is going.
How do I book a baseline?
Send us your SBI number and your hectares and we will send a written quote within two working days. Get a quote.
Part of our guide to soil carbon measurement for farms. Related: why once a year · what 150 hectares means · accuracy stated.
