The Danish Climate Act has set a target that Denmark must reduce greenhouse gas emissions by 70%. by 2030 compared to the level in 1990. And with the Folketing's "Agreement on green transition of Danish agriculture", the focus on agricultural emissions is high. Longterm, the goal is for Denmark to be a climate-neutral society by 2050.

"(…) It is a colossal challenge that requires strengthened collaboration, increased capacity for research, innovation and rapid implementation, as well as not least massive investments in new technology and changed land use," writes head of the Department of Agroecology Jørgen E. Olesen in a chronicle on ing.dk. (in Danish)

It requires new technologies and collaborations if the climate plan for Danish agriculture is to be achieved. And that is exactly what is in focus in the Innovation Fund project ReDoCO2.

Lowland and peatland soils

Agricultural area is not a homogeneous size, and when Jørgen E. Olesen talks about changed land use, it requires different approaches depending on the type of area in question. Lowland and petland have been part of the debate many times as they contain large amounts of carbon. For peat soils, this is approx. 12%, while carbon-rich lowland soils contain more than 6%.

The peat soils can be an obvious place to look at the possibilities for changed land use. But what exactly are peat soils? Section leader Mogens H. Greve from the Department of Agroecology has a good explanation for this:

“Peat soils are areas with a very high carbon content. They are formed because plant material is deposited year after year while the soil is still saturated with water. As long as the area is wet, the soil remains low in oxygen, and therefore the plant material cannot be metabolized by the soil's microorganisms. They need oxygen for that process. The plant material does not rot, and CO2 is stored in the soil as carbon instead of being emitted as greenhouse gas.”

Intensification has led to drained peat soils

Developments in agriculture have led to increased intensification, and this has meant drainage of lowland areas, including peat soils. The areas have been drained so that it has been possible to harvest sphagnum or cultivate the land.

“When a peat or lowland area is drained, oxygen enters the microorganisms in the soil, which means they can decompose the deposited plant material. So, areas that did not previously emit very much CO2 suddenly become one of the major sources of greenhouse gas emissions. However, if we take the peat soils out of farming again, stop the drainage and rewet the areas, it is actually possible to slow down the emission of CO2 from these carbon-rich soils. But we need to map the areas so we know where to start to get the biggest reduction in CO2,” explains Mogens Greve, who is part of the ReDoCO2 project. The aim is to develop methods to map the Danish peat soils in order to rewet areas with the greatest possible climate gain.

Decision-making tool for future selection

With the help of drone-mounted geophysical sensors, field data, artificial intelligence and 3D software, the partners in ReDoCO2 will revolutionize the mapping of peat soils in Denmark, so that rewetting not only will be easier and more accurate, but also as climate efficient as possible.

In addition to Aarhus University participants in ReDoCO2 are Aalborg University, Region Midtjylland, I · GIS and SkyTEM. Together, they will develop a screening tool that, with great precision and a high degree of detail, will be able to map large areas of peat soil. The goal for the tool is to be able to uncover the soil content and potential for reducing CO2 emissions.

"We want to develop a tool that can set up different scenarios, which show net CO2 emissions at the status quo, cessation of agricultural operations and rewetting of the soil, respectively," explains Niels Peter Jensen, CEO of I-GIS.

The tool is intended as a decision-making tool that can be used in prioritizing which lands should be rewetted first in order to achieve the greatest possible climate effect.

"It is therefore important to ensure the necessary cooperation with both the Danish Agency for Agriculture and the Danish Environmental Protection Agency, so that we create the best opportunities for the new data to be used in the work with the climate-peatland scheme and other places where it makes sense," explains Henrik Vest Sørensen, Chief Consultant at the Central Jutland Region.

ReDoCO2 can help decision makers

The government's new agricultural plan outlines a plan for a climate reduction of 55 to 65 % by 2030, that equates to between 6.1 and 8 million tons of CO2. A part of the plan is to rewet large areas of peatland.

“The parties to the agreement […] agree that farmers must be able to extract and rewet as many lowland soils as possible, that the current potential for extraction of carbon-rich lowland soils must be exhausted and that the tracks for further set-aside must be laid. It is the parties' ambition that 100,000 ha lowland including areas bordering lowland be set aside.” Source: Altinget.dk (in Danish)

But only quite a few acres have been rewetted. Among other things, this is related to challenges regarding the EU's support for agriculture. But also, the uncertainty about where to achieve the greatest effect comes into play.

"As it looks now, the peatland schemes are bottom-up driven by landowners, which means that it is the wettest areas that are being rewetted. But if we are to have a great effect, it should be the best drained peat soils that need to be rewetted instead. It is not straightforward, because farmers usually get large yields from these areas. Therefore, there is a need for a top-down tool, run by the state, so that we can rewet the peat soils with the greatest effect. We hope that our tool can provide the necessary insight into which soils can achieve the greatest effect here and now,” explains Niels Peter Jensen.

And according to the partners in ReDoCO2, an analysis of Denmark's peat soils is necessary, as the maps that are used today to assess the quality of the peat soils are from 2010.

"It is more than 10 years ago, and a lot has happened since. Peat soils are not a static quantity. The peat decreases in size as the plant material decomposes. This also means that action has to be taken soon, because as the peat shrinks, the potential for using the areas to reduce CO2 emissions correspondingly disappears. And that is precisely why the ReDoCO2 project is so important, as in a relatively short time we will be able to help decision-makers make well-informed priorities in relation to the extraction of peat soils from agriculture in Denmark,” says Mogens H. Greve.