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Potatoes are one of the world’s most important staple crops — but aligning potato production with regenerative agriculture is tough. Yet pioneering farmers are proving it’s possible, with benefits for soil health, stable yields, and lower carbon emissions.
In this webinar, we went behind the scenes with real farmers in our programme to share farm-level data, success stories, and lessons learned. The goal: to demonstrate that transitioning potato systems to regenerative models is not just possible — it’s already happening.
What you’ll learn from this session:
Who is this for?
This session was designed for potato processors, sustainability managers, agri-food decision-makers, and agriculture teams looking to:
Q&A from the audience
How can I support the entire rotation of a farmer if I only source potatoes?
Response:
At Soil Capital, we offer two solutions when you only source potatoes:
Can your certificates be used in carbon accounting for Scope 3 targets?
Response:
Yes, many of our clients already use Soil Capital certificates for carbon insetting. Our methodology and certificates are ISO certified and align with CSRD, GHGP, and FLAG guidelines.
Can you provide detailed examples of "right cover crops"?
Response:
There's no single "right" cover crop. Each mix depends on the region, materials available on the farm, the farmer's investment capacity, rotation needs, and ambitions. Basic cover crops might last 2 months and contain mustard and phacelia. More complex "Biomax" mixes contain over 5 species (including legumes). Relay cover crops can protect soil during extended intercropping periods.
When you say "reduce mineral fertiliser" do you mean nitrogen only? Or do you recommend reducing other fertilizer inputs too i.e. P, K, S, Mg, Ca?
Response:
We don't specifically recommend reducing fertilizers. Rather, we suggest that by incorporating legumes into rotations, using organic fertilizers, and maintaining a well-functioning system, fertilizer reductions naturally occur. This applies not just to nitrogen but potentially to all fertilizer types. However, this isn't a simple change to implement—it requires good management practices, including soil analysis, careful observation, and thorough knowledge of your soil.
What is the average time it takes for a farmer to go from scenario 1 to scenario 8?
Response:
Reminder: These were simulations. The timeline depends on the farmer's commitment, resources, and system adaptability. Some farmers achieve impressive results quickly, but the overall transition typically takes up to 10 years. (Note: A transition is never truly complete.)
Can you tell us the Nitrogen quantities that cover crops could bring in?
Response:
The nitrogen contribution depends on cover crop composition, biomass produced, and previous crop residues. Non-legume cover crops capture residual nitrogen from previous crops, while legume cover crops can return up to 100 kg of nitrogen with sufficient biomass. Not all nitrogen will be immediately available to the next crop, as release is gradual and some losses occur. The MERCI method can help evaluate both nitrogen capture and release rates.
Is the nitrogen reduction driven by different potato varieties, better fertilizers, or the fact that regenerative practices are supplying mineralized nitrogen (e.g., from legumes in the cover crop winter before potatoes)?
Response:
Primarily because regenerative practices supply nitrogen that would otherwise come from synthetic inputs. Different varieties and improved fertilizers can contribute too, but their impact is smaller and harder to estimate. Additionally, these alternative options tend to be quite costly.
Regenerative agriculture is broader than carbon. Do you also look at/monitor emissions to water (N, PPP) or biodiversity?
Response:
Yes, our program includes a Beyond Carbon module that examines farm performance holistically across five domains: soil health, biodiversity, water management, climate, and farm socio-economics. We measure 31 indicators in Beyond Carbon, which are scored and aggregated into a single farm score providing a comprehensive sustainability assessment.
Can you rank the changes in practice in terms of importance? What can a farmer do if they can't source manure? This is sometimes difficult (at least in the UK) if they farm in arable-only regions.
Response:
Cover crops are the most important starting point—they protect soil, return carbon, recycle nutrients, and capture atmospheric nitrogen. If economically viable, retaining straw on fields after harvest is another option. Organic fertilizers are relatively easy to implement, though availability and cost present challenges. When market conditions allow, changing rotation patterns (adding new extensive crops) is straightforward. Reducing tillage and inputs requires more careful planning and preparation.
What can a grower earn with this?
Response:
This varies from farm to farm, ranging from 0.5 to 2 Soil Capital units per hectare in the best case scenarios.
Do you also have information or experience with the downsides of cover crops, such as wireworms, snails, etc.?
Response:
We're familiar with the challenges cover crops can present for potato growers, and many of our farmers have firsthand experience with these issues. These problems typically stem from improper cover crop management. The key is selecting appropriate species, planting at optimal times using suitable methods, and destroying cover crops correctly for your specific context. For example, incorporating buckwheat and mustard can help manage wireworm populations, while preventing undecomposed residue in ridges helps avoid diseases like Rhizoctonia or scab.
How do you monitor and stimulate carbon sequestration?
Response:
We monitor and simulate carbon sequestration using the DNDC model from Regrow.
What is crucial for the right destruction of cover crops in spring?
Response:
Destroying cover crops at the optimal stage is essential—when the carbon-to-nitrogen (C/N) ratio isn't too high. This enables quick residue decomposition, prevents planting interference, and avoids undecomposed organic matter in ridges that could cause disease. Cover crops can be terminated either chemically to prevent regrowth or mechanically with a scalping machine. For a low C/N ratio, use appropriate cover crops (especially legumes) and destroy them at the right time—we recommend before March 15. Shredding cover crops and performing light tillage helps residues decompose faster and prepares soil for planting.
How did you calculate the GHG emissions? Can you say more about the methodology?
Response:
We calculate GHG emissions and sequestration using two complementary models: DNDC (hosted by Regrow) and CFT. These models analyze verified primary field management data that farmers submit annually through our app. The DNDC model specifically handles soil-borne emissions and carbon storage, while the CFT model accounts for all non-soil emissions.
What about reducing fungicide application and other crop protection products?
Response:
Reducing fungicide applications and other crop protection products has minimal impact on the greenhouse gas balance. Nevertheless, we continue to track these indicators.
Fertilization... what about microbiological origins: bacteria (including atmospheric N fixers) and fungi?
Response:
Adding biostimulants and inoculating soil with beneficial microorganisms can be an excellent way to reduce mineral nitrogen use and lower the associated emissions.
Is it still time to plant cover crops this year or is it too late?
Response:
Cover crops can still be planted now. They can actually be planted as late as winter wheat. While they won't produce much biomass before winter, their roots will remain active throughout winter and generate biomass in spring if not destroyed too early. For late planting, species selection is crucial—choose cool-season varieties like rye, hairy vetch, phacelia, turnip rape, and crimson clover.
Should potato processors be paying growers to allocate their farm carbon removals to their Scope 3 business carbon reduction? Or should we expect the allocation of this removed carbon as part of the supply chain?
Response:
Yes, they should. Farmers deserve financial support for the risks they undertake. The cost of transition should be shared among all value chain participants who benefit from and claim the carbon reductions/removals.
Is there a risk mitigation service/insurance proposed to farmers?
Response:
There are solutions available in the market, but Soil Capital does not offer one.
The vast reductions are from soil carbon sequestration from cover crops - have you been measuring to validate that the carbon accruals in soil are actually happening and not just modeled?
Response:The DNDC model is calibrated and validated for the crops and geographies where we operate. This means the model outputs have been verified with ground-truth measurements—directly measured SOC stocks from peer-reviewed papers, scientific articles, and reliable datasets relevant to our crops and regions.
The data you're describing verifying are the inputs - I'm asking about the results the model produces. Does anyone check if the model estimates match actual measurements?
Response:In addition to using validated models, Soil Capital has initiated a parallel validation process using real field measurements from our farming community. We've begun an extensive sampling campaign that will be repeated in 5 years to confirm that our model outputs closely reflect reality.
Potatoes are one of the world’s most important staple crops — but aligning potato production with regenerative agriculture is tough. Yet pioneering farmers are proving it’s possible, with benefits for soil health, stable yields, and lower carbon emissions.
In this webinar, we went behind the scenes with real farmers in our programme to share farm-level data, success stories, and lessons learned. The goal: to demonstrate that transitioning potato systems to regenerative models is not just possible — it’s already happening.
What you’ll learn from this session:
Who is this for?
This session was designed for potato processors, sustainability managers, agri-food decision-makers, and agriculture teams looking to:
Q&A from the audience
How can I support the entire rotation of a farmer if I only source potatoes?
Response:
At Soil Capital, we offer two solutions when you only source potatoes:
Can your certificates be used in carbon accounting for Scope 3 targets?
Response:
Yes, many of our clients already use Soil Capital certificates for carbon insetting. Our methodology and certificates are ISO certified and align with CSRD, GHGP, and FLAG guidelines.
Can you provide detailed examples of "right cover crops"?
Response:
There's no single "right" cover crop. Each mix depends on the region, materials available on the farm, the farmer's investment capacity, rotation needs, and ambitions. Basic cover crops might last 2 months and contain mustard and phacelia. More complex "Biomax" mixes contain over 5 species (including legumes). Relay cover crops can protect soil during extended intercropping periods.
When you say "reduce mineral fertiliser" do you mean nitrogen only? Or do you recommend reducing other fertilizer inputs too i.e. P, K, S, Mg, Ca?
Response:
We don't specifically recommend reducing fertilizers. Rather, we suggest that by incorporating legumes into rotations, using organic fertilizers, and maintaining a well-functioning system, fertilizer reductions naturally occur. This applies not just to nitrogen but potentially to all fertilizer types. However, this isn't a simple change to implement—it requires good management practices, including soil analysis, careful observation, and thorough knowledge of your soil.
What is the average time it takes for a farmer to go from scenario 1 to scenario 8?
Response:
Reminder: These were simulations. The timeline depends on the farmer's commitment, resources, and system adaptability. Some farmers achieve impressive results quickly, but the overall transition typically takes up to 10 years. (Note: A transition is never truly complete.)
Can you tell us the Nitrogen quantities that cover crops could bring in?
Response:
The nitrogen contribution depends on cover crop composition, biomass produced, and previous crop residues. Non-legume cover crops capture residual nitrogen from previous crops, while legume cover crops can return up to 100 kg of nitrogen with sufficient biomass. Not all nitrogen will be immediately available to the next crop, as release is gradual and some losses occur. The MERCI method can help evaluate both nitrogen capture and release rates.
Is the nitrogen reduction driven by different potato varieties, better fertilizers, or the fact that regenerative practices are supplying mineralized nitrogen (e.g., from legumes in the cover crop winter before potatoes)?
Response:
Primarily because regenerative practices supply nitrogen that would otherwise come from synthetic inputs. Different varieties and improved fertilizers can contribute too, but their impact is smaller and harder to estimate. Additionally, these alternative options tend to be quite costly.
Regenerative agriculture is broader than carbon. Do you also look at/monitor emissions to water (N, PPP) or biodiversity?
Response:
Yes, our program includes a Beyond Carbon module that examines farm performance holistically across five domains: soil health, biodiversity, water management, climate, and farm socio-economics. We measure 31 indicators in Beyond Carbon, which are scored and aggregated into a single farm score providing a comprehensive sustainability assessment.
Can you rank the changes in practice in terms of importance? What can a farmer do if they can't source manure? This is sometimes difficult (at least in the UK) if they farm in arable-only regions.
Response:
Cover crops are the most important starting point—they protect soil, return carbon, recycle nutrients, and capture atmospheric nitrogen. If economically viable, retaining straw on fields after harvest is another option. Organic fertilizers are relatively easy to implement, though availability and cost present challenges. When market conditions allow, changing rotation patterns (adding new extensive crops) is straightforward. Reducing tillage and inputs requires more careful planning and preparation.
What can a grower earn with this?
Response:
This varies from farm to farm, ranging from 0.5 to 2 Soil Capital units per hectare in the best case scenarios.
Do you also have information or experience with the downsides of cover crops, such as wireworms, snails, etc.?
Response:
We're familiar with the challenges cover crops can present for potato growers, and many of our farmers have firsthand experience with these issues. These problems typically stem from improper cover crop management. The key is selecting appropriate species, planting at optimal times using suitable methods, and destroying cover crops correctly for your specific context. For example, incorporating buckwheat and mustard can help manage wireworm populations, while preventing undecomposed residue in ridges helps avoid diseases like Rhizoctonia or scab.
How do you monitor and stimulate carbon sequestration?
Response:
We monitor and simulate carbon sequestration using the DNDC model from Regrow.
What is crucial for the right destruction of cover crops in spring?
Response:
Destroying cover crops at the optimal stage is essential—when the carbon-to-nitrogen (C/N) ratio isn't too high. This enables quick residue decomposition, prevents planting interference, and avoids undecomposed organic matter in ridges that could cause disease. Cover crops can be terminated either chemically to prevent regrowth or mechanically with a scalping machine. For a low C/N ratio, use appropriate cover crops (especially legumes) and destroy them at the right time—we recommend before March 15. Shredding cover crops and performing light tillage helps residues decompose faster and prepares soil for planting.
How did you calculate the GHG emissions? Can you say more about the methodology?
Response:
We calculate GHG emissions and sequestration using two complementary models: DNDC (hosted by Regrow) and CFT. These models analyze verified primary field management data that farmers submit annually through our app. The DNDC model specifically handles soil-borne emissions and carbon storage, while the CFT model accounts for all non-soil emissions.
What about reducing fungicide application and other crop protection products?
Response:
Reducing fungicide applications and other crop protection products has minimal impact on the greenhouse gas balance. Nevertheless, we continue to track these indicators.
Fertilization... what about microbiological origins: bacteria (including atmospheric N fixers) and fungi?
Response:
Adding biostimulants and inoculating soil with beneficial microorganisms can be an excellent way to reduce mineral nitrogen use and lower the associated emissions.
Is it still time to plant cover crops this year or is it too late?
Response:
Cover crops can still be planted now. They can actually be planted as late as winter wheat. While they won't produce much biomass before winter, their roots will remain active throughout winter and generate biomass in spring if not destroyed too early. For late planting, species selection is crucial—choose cool-season varieties like rye, hairy vetch, phacelia, turnip rape, and crimson clover.
Should potato processors be paying growers to allocate their farm carbon removals to their Scope 3 business carbon reduction? Or should we expect the allocation of this removed carbon as part of the supply chain?
Response:
Yes, they should. Farmers deserve financial support for the risks they undertake. The cost of transition should be shared among all value chain participants who benefit from and claim the carbon reductions/removals.
Is there a risk mitigation service/insurance proposed to farmers?
Response:
There are solutions available in the market, but Soil Capital does not offer one.
The vast reductions are from soil carbon sequestration from cover crops - have you been measuring to validate that the carbon accruals in soil are actually happening and not just modeled?
Response:The DNDC model is calibrated and validated for the crops and geographies where we operate. This means the model outputs have been verified with ground-truth measurements—directly measured SOC stocks from peer-reviewed papers, scientific articles, and reliable datasets relevant to our crops and regions.
The data you're describing verifying are the inputs - I'm asking about the results the model produces. Does anyone check if the model estimates match actual measurements?
Response:In addition to using validated models, Soil Capital has initiated a parallel validation process using real field measurements from our farming community. We've begun an extensive sampling campaign that will be repeated in 5 years to confirm that our model outputs closely reflect reality.
