Carbon farming project update

Clara Robinson, Carbon Farming Project Manager takes a look at the emerging results from her work looking at carbon calculators 

Background

At RSPB’s Hope Farm we have been working on a study using three carbon calculators; Farm Carbon Toolkit, Cool Farm Tool, and Agrecalc, to provide insight into the usability and suitability of each tool for different farming systems. Hope Farm was the arable case study for this project, and upon completion of the three calculators, there is a swing of approximately 1,250 tonnes of CO2e between the highest and lowest result. The results are broken down across a few sectors of the farm business, as follows: Residue Management, Fertiliser Production, Soil / Fertiliser, Crop protection, Carbon Stock Changes (Sequestration), and Energy Use. 

Figure one – Total Tonnes of CO2e emissions for each calculator

Usability

Each calculator covers various aspects of carbon from an agricultural perspective, but of these three, there does not seem to be one that captures them all. The below table demonstrates the sectors available for each calculator at the time of writing. One tick denotes that this is available, and a cross that this is not available, with the additional ‘+’ symbol to show that this tool asks for this information in depth or has a range of options for input available above the offerings of the others. 

Figure two - features offered by each calculator

In terms of accessibility, not all these calculators are free to use, with Farm Carbon Tool Kit being the only one with full access for free. Cool Farm Tool is also free to use but there are added options available with payment, and Agrecalc is paid access only. We were fortunate to be given access for the duration of this study. Each tool is also structured in a similar way with the use of tabs for navigation, though Cool Farm Tool requires different assessments per crop, which proves tricky when pulling the results together for a full farm picture when using the free to use version. Agrecalc also stood out as providing the best customer service.  

Output results

Figure three- Tonnes of CO2e per subsection and the given total

Farm Carbon Toolkit provided the lowest emissions data, to the extent that this had the farm as sequestering CO2, at -858.79 tonnes of CO2e. We think this huge amount of sequestration potential comes from the advanced ability to input tree data, including hedgerows, and the broad range of stewardship options that are available. Entering our SOM LOI data also had a significant impact on sequestration data. However, this calculator may have missed emissions that would come from fertiliser production, as this is not included as it is with the other two calculators. Additionally, this calculator does have the capability to include building materials and a vehicle inventory, but we did not complete this due it being incompatible with comparison with the other tools.

Cool Farm Tool provided our highest output figure at 406.46 tonnes of CO2e emitted. Interestingly, this tool also had a high level of sequestration potential for the farm, at just over 1,000 tonnes CO2e, but this has been overshadowed by higher figures for each sector explored, in comparison to the other two calculators. For example, for off farm transport this calculator was over 450 tonnes of CO2e more than Farm Carbon Toolkit, whereas Agrecalc does not provide this input and so cannot be compared. The reasoning for these stark differences is likely as simple as differing methodologies and source calculations for the software, though it is surprising to see such a dramatic difference between this and the lowest result. 

Agrecalc is the more moderate of the three calculators in terms of the output, at just 317.94 tonnes of CO2e. This calculator does have the farm showing some sequestration potential, but this is just -23.35 tonnes CO2e., and despite this low sequestration figure, the overall output of emissions for the farm remains low in comparison to Cool Farm Tool. This is because the emissions figures across each sector for this tool are lower than the other two calculators. This may also be due to differing methodologies and source calculations, but from our understanding may in part be due to the development process of Agrecalc, which was formerly predominantly aimed at livestock farming, while Hope Farm is arable, meaning that these calculations may not be in line with the general guidance thus far.

Conclusion

In summary, the calculators provided broader results than anticipated, but after going through the process of completing each calculator, it is apparent that these results are so different because each calculator is ultimately working off its own set of calculations, and it is clear why the results are so varied – each calculator simply measures different things. Our next steps are to complete the case studies we are working on with our volunteer participant farmers to gain further feedback on the tools, and to publish a report going more in-depth into the methodologies and behind the scenes workings of the tools.

If you would like more information about the project, please contact us at the following email addresses: clara.robinson@rspb.org.uk / sophie.arnold@rspb.org.uk - thank you.