HUMUS+ Modell ÖkoregionKaindorf

Result-based contract solution - farmers follow recommended measures to build up humus (=soil organic matter) in soil, sequester CO2 and receive a fee per ton of stored CO2. Companiesfinance humus build-up and soil carbon storage by buying CO2 certificates.


The HUMUS+program is a contract solution developed for voluntary trading of CO2 certificates: Based on an initial soil sampling at the start of the contract (by a certified civil engineer and accredited national laboratory), farmers set own measures to increase the humus content in their soils. After a period of five to seven years (according to the farmers needs), humus content is determined again by a second soil sampling. An increase in humus content is converted into additional tons of CO2 stored in soil. Farmers receive a success fee of 30€ per additional ton of CO2 stored, which is financed by companies who voluntarily compensate their unavoidable CO2 emissions. The amount of CO2 purchased by the companies cannot be traded. After the payment, farmers must guarantee that the increased humus content remains in place for at least five years. This requirement is verified by a third soil sampling taken five years after the payment. Decreases in humus levels lead to partial or complete refunding of the success fee. Everything from contracts and the carbon verification to the emission trading is organized and managed by an Ltd belonging to the association HUMUS+. The association itself is responsible for an education program set up to educate and advice HUMUS+farmers on the measures set by them.


• Main objective: humus (soil organic matter) accumulation and soil carbon sequestration
• Higher soil fertility – soil organic matter supports life in the soil, which is the basis for vital crops and reduces the need for mineral fertilizers and pesticides
• More reliable harvests through resilient crops – living soil supports resistant plants in the face of global climate change
• Keeping the soil in place – humus-rich soils rich are more resistant against erosion by heavy rainfalls, flooding or wind
• Humus-rich soils store lots of water, which helps to maintain stable yields during droughts
• Keeping the groundwater clean – soils rich in humus can fix more nitrate and prevent groundwater pollution
• Climate change mitigation through CO2 fixation – soil organic matter contains about 60% carbon, hence building up soil humus removes CO2 from the atmosphere and helps to mitigate global overheating

Data and Facts - Contract

• Number of farms: approx. 380 farmers (June 2022) 
• Area of implementation: 5.100 ha (June 2022) 

Involved parties: 
HUMUS+: The non-profit association is coordinator of the humus built up program. It was a project amongst others implemented by the association Ökoregion Kaindorf and became its own association in 2021 due to its growth and success. 
• Certificate trading: is handled by a Ltd. owned by the association. The Ltd. organizes the HUMUS+certificate trading and everything connected to it. All other aspects of the HUMUS+program (education program, consulting services) are handled via the association. 
• Farmers: The program started in 2007 with three farmers. As of 2022, 380 farmers are participating. Farmers participation is now the restraining factor, as demand is higher than provision and certificates are currently sold out. 
• Companies and private persons: HUMUS+certificates are bought by companies and private persons who aim to compensate their unavoidable CO2 emissions. 
Management requirements for farmers: HUMUS+ provides practical principles for humus accumulation in soil and suggests best-practices including use of cover crops, no-till practices, intercropping and compost application. However, there are no obligatory requirements such as mandatory management measures. Farmers are free in their choice of how to increase humus content on their fields.
Controls/monitoring: The participating farmer commits himself only to pay for the first soil sampling. He/she can leave the program at any time up until a success fee has been payed after the second sampling. Then, the third sampling becomes mandatory. Each field registered for the Program is thus subject to a minimum of one soil sampling, which is carried out by a certified civil engineer. Soil samples are analysed for soil organic carbon, total nitrogen, pHCaCl2, CAL-extractable phosphorus and potassium by the Department for Soil Health and Plant Nutrition, Austrian Agency for Health and Food Safety (AGES). In addition, samples may be analysed according to the method of Albrecht/Kinsey for exchangeable cations, total sulphur, available and total phosphorus as well as a range of trace elements (not mandatory). The first soil sampling determines baseline humus levels (25 GPS-located samples per field, mixed and analysed as a compound sample). A second sampling (success sampling) is conducted in the same manner five to seven years later to quantify changes in humus content. From the increase in humus, the total amount of CO2 sequestered is calculated. The farmer can then claim a success fee of 30 € per ton of CO2 sequestered (i.e. two thirds of the certificate price, for legal reasons the absolute price per ton is not guaranteed). After receiving the fee, the HUMUS+farmer has to guarantee the level of buildup humus for five years. This is controlled by a third sampling (control sampling). In case an increase in humus above levels from the success sampling is measured, farmers can claim further success fees and the program is prolonged for another five years. Decreases in humus content can lead to partial or complete refunding of the success fee. Farmers pay for all soil samples.
Renewal / termination: 
• Renewal of the contract: The option of renewal is regulated in the contract solution; the contract can be renewed easily. 
Termination: Termination is always possible, except in case a success fee has been payed after the second sampling. Then, the third sampling becomes mandatory. 
Conditions of participation: Farmers may take part with one or more fields, each between 1 and 5 ha in size. The farmers have to pay the initial soil sampling. Other than that, the farmers do not agree to any liabilities. 
Risk/uncertainties of participants: The main risk for farmers is not building up humus and therefore not receiving the success fee, even if there might have been investments and changes in management style. Another risk might arise from reduced demand in CO2 certificates. However, this does not seem likely as demand has by far exceeded supply for years. In any case, the farmer is guaranteed two thirds of the certificate price as a success fee. 
Links to other contractual relationships: There is no direct link with other contractual solutions, and farmers are free to participate in other agro-ecological programs (e.g. CAP, ÖPUL, AMA, …). The farmers are bound to the HUMUS+Program though, meaning they cannot take part in a similar, privately organized program of humus build-up and emission certificate trading.

Problem description

The coordinator of the contract solution is the association HUMUS+ which is located in the Ökoregion Kaindorf. The whole region has set itself the goal of significantly reducing its CO2 emissions to achieve net CO2 neutrality. The change in agriculture towards monocultures, increased use of pesticides and intensive tillage in the last decades has led to a major loss of humus and thereby to the release of CO2 into the atmosphere. There is a strong need for action to prevent the progression of climate change and to better prepare our soils for future climate effects

Context features

Landscape and climate: The HUMUS+program is not restricted to a special region in Austria, all farmers throughout Austria can participate. Through recent collaboration there are now also HUMUS+farmers in Slovenia and efforts are being made to expand the program further across Europe.
Farm structure: : In general, the HUMUS+program is free for any agricultural management (except forestry), however up to now most of the farmers are arable farmers. There is no specific business type taking part regarding intensity, size, age of farmers, etc.

Success or Failure?

The HUMUS+program represents a successful contract solution. The number of participants clearly increased since its initiation in 2007 and is still increasing. On the demand side, the demand for certificates currently exceeds the provision by the farmers. Except for the payment for the initial sampling, there are no obligations for the famer in the program. Via the HUMUS+program, farmers moreover get access to educational events and network meetings to exchange with other farmers on the subject of sustainable soil management.
There is huge potential for climate-regulation via soil carbon storage. Results so far show that humus accumulation and carbon sequestration removes CO2 from the atmosphere in relevant quantities (on average 6 tons CO2 per hectare and year). Through the result-based character of the payment, only the measured environmental success (CO2 stored as humus) is paid.

Reasons for success :

• Farmers are free in their management decisions, the program only provides best-practice suggestions
• No liabilities for the farmer, except payment for the initial soil sampling
• Program is accompanied by educational measures and helps to connect farmers into a humus community
• Payment for the farmers comes from the private sector. Demand for certificates has greatly exceeded provision by the farmers for the last years.
• In addition to CO2 sequestration, humus formation has further benefits for the farmer (soil fertility, etc.)

SWOT analysis

Main Strengths
1. The contract solution is easy to understand.
2. Possibility of an additional income for farmers
3. Implicit social component (awards, networking, training, image..)
4. No prescribed and obligatory management measures; Farmers can freely and flexibly decide on management measures to achieve the Program goals (i.e. increase humus content)
Main Weaknesses
1. Full flexibility in the management measures can lead to wrong decisions (e.g. application of organic and synthetic fertilizers not based on plant and soil demand procure high N losses)
2. Farmers risk to not achieve changes in humus contents even if management changes and/or investments have been carried out
3. Considerable costs for setting up the program;
Need to bridge the gap between project start and the first sales of emission certificates
4. Up to now implemented on only a small area; high potential of growth.
Main Opportunities
1. Raising climate awareness of society
2. Result-oriented approaches in the new CAP
3. Humus accumulation as an adaptation to climate change
4. Increasing demand for emission certificates e.g. from the private sector
Main Threats
1. Slow process of humus accumulation, binding period in contracts for farmers quite long.
2. Climate change might affect rates of humus accumulation
3. Companies might lose interest in certificates
4. Unharmonized carbon prices can lead to a poor competitiveness against other emission traders
5. Risk of trade offs and discussions, if measures for humus accumulation result in effects on other public goods, (e.g. quality of groundwater, biodiversity, etc.)

Main external factors

Political/governance, economic/market, social, technological, legal and environmental factors can all have a strong impact on the success of contract solutions. In this case study an in-depth analysis found that the following, selected factors were of specific importance.

Online field maps as a supporting tool: 
CO2 storage is visualized via online field maps. The documentation of the plots is supported by a specifically developed database. The database contains information about 
the farm, 
the humus plots, 
soil samples and certificates. 
It enables georeferencing of the humus plots. 
GPS-supported soilsampling: 
Soil sampling is GPS-supported which ensures that initial soil samples and soil samples for the measuring of results are located in the same spot.

Implicitsocial components are included in the case study: 
(1) HUMUS+farmers receive their success fees (via a cheque) in a public ceremony. A picture of the farmers is published in local newspapers, which increases social recognition. 
(2) The program helps to network farmers into a humus community by hosting a regular meeting “HUMUS+Stammtisch”, where farmers exchange their knowledge and experiences with humus accumulation. 
(3) The program fits the recent social discussion on climate change, e.g. driven by initiatives such as Fridays for Futures. Entering the program is perceived as being “part of the solution” for both farmers and buyers.

Developmentsin the HUMUS+Program since 2020: 
- Due to growing interest of farmers as well as companies, HUMUS+ became its own association in 2021. The new program manager now is Mag. Jochen Buchmaier who has a strong background in permaculture and regenerative measures such as agroforestry and key-line design. 
- A collaboration with Slovenia was successfully built and around 30 local HUMUS+farmers are already working according to the suggestions of HUMUS+ to successfully build up humus and regenerate soils in Slovenia. A lot of interest is also coming from other countries in Europe to collaborate and extend the HUMUS+program. 
- The area included in the program rose to more than 5000 ha of land that is now managed sustainably aiming to regenerate the soil, build up humus and store CO2 in the ground. 
- A new advisory program was developed to supply HUMUS+farmers with in-depth-knowledge over the course of a whole year. 
- Due to the growing number of similar programs, it is becoming necessary to define quality standards and improve cooperation between stakeholders. HUMUS+ is therefore initiating a Consortium for regenerative agriculture and carbon farming.


The payment depends on a defined result (stored CO2 as humus per hectare, measured)


Climate regulation-carbon storage

Soil quality (and health) / Soil protection



Participation in the contract solution is open to all farmers across Austria and Slovenia


Contract conclusion:

Written agreement

Payment mechanism:

non-tradable emission certificates


• The HUMUS+farmer receives a success fee of currently 30 € per ton of CO2 sequestered in humus (i.e. two thirds of the certificate price, for legal reasons the absolute price per ton is not guaranteed). • Companies pay 45 € per ton of CO2. The difference of 15 € (before taxes) remains with the Ltd. for administration of the contract solution. • As of 2022, the association paid 500.000 € to participating farmers.

Start of the program:

The HUMUS+program started in 2007.


The program is still running.

Feel free to contact us for any further informations.


Legal notice: The compilation of the information provided in the factsheets has been done to our best knowledge. Neither the authors nor the contact persons of the presented cases may be held responsible for the use which may be made of the information contained therein.