The soil needs carbon

It is imperative to maintain or increase soil organic carbon for protecting the climate and improving soil fertility. Researchers from Aarhus University are partners in a new international project that will develop and disseminate knowledge in this area.

2017.11.29 | Janne Hansen

Among the measures that can increase soil carbon storage are more plant coverage, improved management of grasslands and longer grazing periods. Photo: Janne Hansen

Carbon is basic for all life on earth. Storage of carbon in agricultural soil ensures soil fertility and contributes to reducing the impact of agriculture on climate change. The question is how we can ensure that the soil contains adequate carbon. 

A new international research project addresses this issue, and researchers from the Department of Agroecology at Aarhus University participate in this together with 22 other partners from 17 different countries all over the world. The three-year project, called CIRCASA, is a Horizon 2020 project that has been granted 2.5 million euros. The aim of the project is to identify knowledge gaps and research needs with regard to storage of soil organic carbon and on the basis of this prepare an international research agenda.

The role of Aarhus University will be to survey stakeholders’ views regarding existing knowledge and needs for new research. These stakeholders include authorities, financial institutions, research and education institutions, agriculture, forestry, businesses, and ngo’s. 

- We will gather the stakeholders’ perspectives on the potential for soil organic carbon management to contribute to climate change mitigation and adaptation, sustainable intensification of agriculture, food security and the UN Sustainable Development Goals. We will then identify and evaluate the possibilities for implementing methods for carbon storage in the soil. On the basis of inputs from stakeholders we will summarise knowledge gaps and research needs, explains Section Manager and Professor Jørgen E. Olesen from the Department of Agroecology at Aarhus University.   


Facts about the project:

Name: Coordination of International Research Cooperation on Soil Carbon Sequestration in Agriculture (CIRCASA)

Grant: 2.52 million euros from EU’s Horizon 2020 programme

Leadership: The research institute INRA, France

Partners: 23 participants from 17 different countries on all continents except Antarctica

Time frame: Three years (2018-2020) 

Interest in optimising soil organic carbon for the sake of soil fertility and greenhouse gas emissions is not new. Jørgen E. Olesen and other researchers from the Department of Agroecology at Aarhus University participate in numerous projects and initiatives in this regard. Three of the latest research projects are SmartSOIL, CarbonFarm and SoilCare. They focus on increasing storage of soil organic carbon using various tools with the aim of increasing soil fertility.    


Read the article ”New tool can help increase soil carbon content and thereby improve soil fertility” about SmartSOIL.) 


Read the article ”More carbon in the soil, please” about CarbonFarm. 


Four per mil per year

Via the Ministry of Environment and Food of Denmark, Denmark also participates in the French initiative ”4 per 1000”. The concept is that if the world can increase its soil carbon storage in the upper 30-40 cm soil layer by 0.4 percent per year, then the annual increase in CO2 emissions can be stopped. 

Among the measures that the French initiative proposes are increased plant coverage, more catch crops, more forests, improved pasture management, extended grazing periods, and improvement of degraded soils. 

- The measures that really make a difference with regard to carbon storage are mulching of straw, and growing of catch crops and grass, says Jørgen E. Olesen, albeit he has his doubts about whether the climate goal of an annual growth rate of 0.4 percent in the soil carbon stocks can be achieved. 


Read the article ”Four per 1000 – is that a good idea?” about the 4 per 1000 concept for reducing agriculture’s greenhouse gas emissions. 


On the other hand, Jørgen E. Olesen believes that the concept has good possibilities in relation to improving soil fertility. He addressed this in his keynote lecture about the perspectives for soil carbon management at the ”4 per 1000” meeting at the climate summit meeting COP23 in Bonn in November 2017. 

Here he mentioned that the full potential of soil organic carbon on crop yield will only be achieved with correct timing of optimal amounts of water and nutrients – in particular nitrogen – and appropriate pest management. 

- The bottom line is that it is important to increase the total production of biomass, so that there is enough to harvest for food, feed and energy, and to return to the soil. There is no doubt that soil carbon content must be improved to ensure a more fertile and functional soil resource. The measures that the 4 per 1000 concept proposes are fully aligned with this goal, says Jørgen E. Olesen. 

For more information please contact: Section Manager, Professor Jørgen E. Olesen, Department of Agroecology, e-mail: jeo@agro.au.dk, telephone: +45 8715 7778, mobile: +45 4082 1659 


Climate-Smart Agri-Food Systems is one of the research areas in which the Department of Agroecology is particularly strong and from which results are delivered in line with national and global societal challenges and goals.

Agro, DCA, Crops, Nature, environment and climate