Land use is the second major source of greenhouse gas (GHG) emissions after fossil fuels, and a major cause of biodiversity loss, with overuse of fertilisers and peatland degradation a driver of both crises. For this reason, the carbon farming approach has received increasing attention in recent years, reflecting the need for agriculture to both contribute to meeting climate objectives and to adapt to climate impacts. In practice, however, these techniques are often ignored in favour of intensive techniques using large amounts of artificial fertiliser, much of it wasted, that can increase greenhouse gas emissions.
What is carbon farming?
Carbon farming refers to farm management practices that aim to deliver climate mitigation in agriculture. This involves the management of both land and livestock, all pools of carbon in soils, materials, and vegetation, plus fluxes of carbon dioxide, methane, and nitrous oxide. It includes carbon removal (sequestration and permanent storage of carbon in soils and biomass), avoided emissions (preventing the loss of already stored carbon), and emissions reductions (e.g., reductions of GHGs below current levels of farm emissions). All farming systems can mitigate, although the level of mitigation potential differs across farm types and different geographies.
Back in 2021, after a two-year study, the European Commission published a technical handbook on how to set up and implement carbon farming in the EU, aimed at helping both private actors – via supply chains or carbon markets – and public authorities start up carbon farming initiatives. Indeed, carbon farming also refers to the business model that aims to upscale climate mitigation by paying farmers to implement climate-friendly farm management practices. The European Commission has already promoted carbon farming in its recommendations on the Member States’ CAP Strategic Plans and continues outlining carbon farming possibilities in its further assessment of the CAP Plans.
To better understand the opportunities of this approach, we met Tashina Petersson, researcher at the Division on Impacts on Agriculture, Forests and Ecosystem Services (IAFES) of CMCC. To identify carbon farming practices, and quantify their contribution to climate mitigation, Petersson is working on a systematic review of the EU experience.
Why adopt the carbon farming approach?
To achieve high productivity in the short term, intensive farming is based on monocultures and large amounts of synthetic fertilisers. Moreover, annual crop rotations are not implemented, and the ploughing is deep. All these practices cause a loss of carbon into the productive process and, of course, other impacts such as the increase of erosion, the reduction of biodiversity or the decrease in water availability.
What are the main benefits of carbon farming?
Farming practices that work with natural processes can have benefits for biodiversity, water, soil health, and animal welfare. In the long term, farmers can also benefit from productivity improvements, reduced costs, and improved farm resilience. Moreover, carbon farming captures more CO2 and increases crop resilience compared to intensive techniques.
How is carbon captured by soil and biomasses?
Photosynthesis is, of course, the engine of CO2 sequestration from the atmosphere. Sooner or later, all biomass produced by plants reaches the soil where it is decomposed by microorganisms. As a result, this organic component of soil, named humus, forms the nutrient supply of all terrestrial ecosystems, including agroecosystems.
What are the most common carbon farming practices?
Carbon farming includes different strategies that can be combined. Most of them were commonly used before the rise of synthetic fertilisers and mechanised agriculture. For example, let’s think about crop rotations, the conservation of hedges, or the use of organic fertiliser (manure and compost) instead of synthetic ones. The planting of rows of trees within arable land and the use of cover crops are other examples.
What are cover crops?
Cover crops are planted to cover the soil rather than for the purpose of being harvested. They manage soil erosion, soil fertility, soil quality, water, weeds, pests, diseases, biodiversity, and wildlife in an agroecosystem. Cover crops can increase microbial activity in the soil, which has a positive effect on nitrogen availability, nitrogen uptake in target crops, and crop yields.
What about productivity? It is often touted as the limiting factor in organic farming.
Most of the scepticism originates from comparing the productivity of intensive farming with that of low-input organic farming. It’s true, the performance of the first is higher. But the productivity of some high-input practices are competitive, especially in the long term. We must keep in mind that intensive farming makes soils progressively less productive and more vulnerable.
And what about CO2 sequestration?
Until soils reach carbon saturation, the most complete carbon farming strategy may compensate for almost all emissions from farming. Some studies report almost one ton of carbon absorbed by soil for each hectare. And what is also worth noting is that these values usually refer to the first 30 centimetres of soil, but soils can be much deeper!
How can crops increase CO2 absorption?
The key to success is mixing different practices: adopting cover crops, using organic fertiliser, leaving prunings and other residues on the ground, planting orchards on arable lands. And of course, carrying out crop rotations, which are better still if done by changing the botanical family every year for four years. Vegetables have a greater capacity to absorb carbon than extensive crops since they require more nutrients.
Are incentives stimulating the adoption of carbon farming in the EU?
Farmers are first and foremost entrepreneurs. For small farms, the gains from the carbon market are still negligible. National and EU incentives fit better with their business but unfortunately, among the reservoirs of carbon, investing in living biomasses and woody products is more convenient than investing in soil. In the current scenario, farmers prefer planting orchards and other trees rather than adopting practices such as cover crop or using organic fertilisers.
Picture: Cover crops on Bryce and Brian Irlbeck farm in Carroll County, IA – NRCS/SWCS photo by Lynn Betts on Flickr
