Direct Measurement
of Soil Organic Carbon

Our Approach

Agricarbon secures reliable and consistent direct measurement of soil organic carbon (SOC) over all soil types and land management systems.

Our efficient core extraction teams and unique analysis technologies significantly lower the cost, ensuring that statistically robust sampling strategies can be implemented, even at scale.

Our high-throughput processing facility uses Dumas dry combustion and bulk density measurements for every sample – the only method sensitive enough to detect changes in soil carbon stock over time.

Quantify your soil carbon stock today.


Sampling Strategy

We typically carry out stratified random sampling – a widely accepted scientific method designed to ensure that samples represent the variable conditions present across the whole measured area, which might otherwise be missed if a simple random point selection or ‘W’ sampling formation is used.

For example, a soil carbon audit for a 100-hectare farm may incorporate more than 1,000 samples from over 300 locations.

Random Sampling - Stratification - Agricarbon - Soil Carbon Measurement - Soil Organic Carbon

Sampling Process

Step 1: Stratification

We begin with a digital mapping exercise, overlaying several data layers with field boundary maps to determine suitable sampling locations. Data layers include soil type, parent material (geology beneath the soil layer) terrain features, and above-ground vegetation. These are used to subdivide each field into 3-5 zones, called ‘Strata’.

For larger projects, strata may aggregate multiple fields and farms, where similar characteristics can be expected to create more homogenous soil carbon conditions.

Step 2: Sample Locations

The number of sampling locations is linked to the size of each measured area. To detect change at the single farm level, this is typically 15 locations per field. These are distributed proportionally across the strata and randomly allocated within the Strata.

GPS coordinates are sent to Field Operators via Agricarbon’s proprietary App.

Sample Collection

Our expert field operators are fast and efficient. Using our Carbon Force platforms – modified ATVs equipped with powerful hydraulic core extractors – the field operations team extracts cores with a wide enough bore to preserve soil structure (including stones) and deep enough to show full soil profile (down to 1m). The soil cores are kept intact in air and water-sealed tubes and refrigerated until processing.

We cover thousands of hectares of land every week and typically complete a whole farm in 1-5 days (depending on size).

Soil Sampling - Agricarbon - Soil Carbon Measurement - Soil Organic Carbon

Depth Layers

Soil cores can be up to 1m long and are subdivided into multiple samples before processing. This allows organic carbon and bulk density to be measured at each depth layer in the full soil profile.

Measuring to depth gives a better picture of total soil carbon – between 30% and 50% of soil organic carbon can be held below 30cm – and ensures that improvements in soil structure or movement of carbon between layers can be captured in the results from repeated measurements.

Soil Sample - Soil Sampling - Agricarbon - Soil Carbon Measurement - Soil Organic Carbon

Soil Compaction

Our hydraulic extractors take a wider bore core than conventional sampling ‘needles’, ‘stitches’ or augurs. This allows us to preserve the soil structure, including stone content, to measure both total bulk density (reflecting soil compaction) and fine earth bulk density (reflecting the amount of soil available to sequester carbon) for every sample and at different depths.

Bulk density is an important indicator of soil compaction and necessary to convert SOC% into tonnes of carbon (SOC% x fine dry bulk density = total tonnes of carbon).

Compaction - Agricarbon - Soil Carbon Measurement - Soil Organic Carbon

Automated Soil Carbon Analysis (ASCA)

At the heart of our service is our Automated Soil Carbon Analysis machine – ASCA – processing thousands of samples quickly with very high consistency and at an ultra-low cost. This ensures large numbers of samples can be analysed individually and accurately, which is vital for measuring changes in soil carbon stock with high certainty and statistical significance.

We do not composite samples; ASCA allows us to analyse every sample individually at ultra-low cost – and build up a detailed picture of SOC% and bulk density across the measured area and down through the different depth layers of soil.

Automated soil sample Processing - Agricarbon - Soil Carbon Measurement - Soil Organic Carbon

Dumas Dry Combustion

ASCA uses Dumas Dry Combustion – the most accurate method for measuring soil organic carbon concentration (SOC%). This method is required to meet international standards for internal carbon accounting and GHG inventories, and carbon credits for the voluntary carbon market (offsets).

ASCA provides far greater analysis consistency than conventional laboratory testing, reducing uncertainty in carbon stock calculations.

Automated Processing - Agricarbon - Soil Carbon Measurement - Soil Organic Carbon

Bulk Density

ASCA measures bulk density for every sample. This tells us how much soil there is in a given volume (e.g., a field), and also gives a measure of soil compaction. Bulk density (BD) can vary across a field as much as SOC% and is essential for calculating soil carbon stock: SOC STOCK = SOC% x BD

Measurement of BD requires separating fine earth from stones and gravel, in a known volume of soil, and weighing each fraction.

ASCA measures the bulk density for every single sample.

Bulk Density - Agricarbon - Soil Carbon Measurement - Soil Organic Carbon


A full report for each project includes a detailed breakdown by field and soil depth. Information about the sampling exercise, data sources, processing parameters, and results are all stored securely to allow future remeasurement, comparison, and analysis.

A comprehensive data trail is stored securely for future audits, carbon accounting, and disclosures.

Results - Stewart Arbuckle - HQ - Agricarbon - Soil Carbon Measurement - Soil Organic Carbon

Bolt-on Services

An additional suite of soil health tests can be added to a soil carbon stock assessment. Packages include basic nutrients, trace elements, and soil carbon dynamics metrics. Enquire about the packages by contacting us today.

Bolt on

"Agricarbon’s innovative technology for soil carbon measurement enables global action to protect and restore our soils for future generations."

Dr Helaina Black, Chief Soil Scientist.

Helaina Black - Soil Sampling - Agricarbon - Soil Carbon Measurement - Soil Organic Carbon

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