State-of-the-art instrumentation is analysing carbon sequestration and emissions of fields − plants wake up early to do their job

The carbon footprint calculation of food doesn’t currently take into account the role soil plays in the climate impact of food production. In fact, soil not only binds carbon when, e.g., grasses are growing, it also generates greenhouse gases. Valio’s goal is to reset milk’s carbon footprint to zero by 2035. Doing this requires more accurate information about how soil factors into the equation. That is why there are currently four Valio farms measuring the carbon balance of soil. The dairy farmers are actually also grass farmers − and while grass is the most important food for cows, it also binds carbon.

Chamber, carbon contraption, box.

Simple nicknames dot the conversations of experts and dairy farmers when talking about the round chambers visible at the Valio farms. These chambers hold state-of-the-art carbon flux sensors that measure the actual carbon dioxide emissions and carbon sequestration of the dairy farm soil. Data is being collected from 10 locations at the four farms, both from mineral soil and form organic peatland.

The measurements aim to determine the impacts that various farming practices, fertilisation, and tillage methods have on the soil’s ability to bind carbon. This will help to find the environmentally smartest ways to farm the land for the needs of dairy cows and improve the soil’s carbon sequestration.

Participating in the project along with Valio is Datasense, which collects and analyses the data, and the Finnish Meteorological Institute, which uses the measuring results and its own data to create modelling for soil carbon footprint assessment needs.

One of the members of the enthusiastic team is Senior Researcher Liisa Kulmala from the Finnish Meteorological Institute. She is a former forester who now wants to find out how field ecosystems function and what their climate impacts are.

“The carbon cycle is a personal passion for me. I’m interested in finding out if climate change can be mitigated in the land use sector,” Liisa Kulmala says.

Carbon flux?

Carbon flux analysers are at the centre of the collaboration project. Carbon flux means the ratio of carbon absorption and emissions, i.e. how much carbon dioxide is sequestered in the soil and how much of it is released into the atmosphere during the measuring period. This process doesn’t happen at the same rate all the time; nature follows its own daily rhythm.

“Plants wake up and start doing their job at about six in the morning. More absorption occurs during sunny weather and less during cloudy weather. Most of the emission happens at night,” explains Datasense CEO Jari Hakkarainen.

The carbon flux analyser is inside a transparent chamber installed in the field parcel being studied. Every half hour, the chamber automatically closes. A microclimate is formed within it and the sensors measure the carbon dioxide reading. If the reading increases during the measuring period, it means that the soil is releasing carbon dioxide into the atmosphere. If the reading decreases, carbon is being sequestered in the soil. The carbon flux analysers take 48 measurements during a 24-hour measuring period, and the average of these gives the daily balance for carbon binding and emissions. Based on the results, it’s possible to calculate the estimated carbon binding and emissions at the hectare level.

The analyser transmits the data via a modem to a cloud, where the data collected from grass fields can be tracked almost in real time. This gives the dairy farmers up-to-date information about what is happening in their own field: the current growth rate, how the peatland compares with the mineral soil, and what the 24-hour measurement average indicates – whether carbon sequestration or emissions is taking place.

Jari Hakkarainen is passionate when talking about the summer 2021 project and the use of technology to achieve carbon-neutral food production. The future looks promising in terms of more accurate estimates, and the data from fields will really change the world.

“In the future we’ll be able to agilely and cost-efficiently produce carbon balance calculations and estimates. And other greenhouse gases too, like methane and nitrous oxide, will be measured in the near future, and it’ll be possible to measure and model bigger areas,” Jari Hakkarainen says.

What happens with the data from the chambers?

The Datasense instrumentation measures and collects precise local carbon balance readings which are supplemented with the Finnish Meteorological Institute’s own data. After a measuring period, the Finnish Meteorological Institute researchers analyse the collected data and use it to refine their own carbon sequestration verification system.

This collaboration will ultimately result in modelling to help determine the annual carbon sequestration and emissions of different soil types and the impacts of actions taken by farmers.

Eventually, the potential of the data will be very visible in the everyday life of farmers: it will be possible to use modelling in Valio’s CARBO® environmental calculator, which dairy farmers can use to get a more precise assessment of their own carbon footprint and the most effective ways to reduce it.

“I feel that our research is very important for the future. Milk production is facing tough climate pressure, and with the more precise calculation of the soil factor, we can develop new ways to reduce milk’s carbon footprint and to verify it,” says Virpi Kling, Development Manager with Valio’s carbon-neutral milk chain team.

Measuring the soil’s carbon footprint is a cooperation project

Valio’s carbon-neutral milk chain collaboration is part of the Business Finland-funded CARBO project (link) in partnership with the Finnish Meteorological Institute, Natural Resources Institute Finland, University of Eastern Finland, Atria Producers, and Yara.

Measuring the soil’s carbon footprint is also done in the Biohila project, which is aiming to produce precise data about the biomass of fields by combining data collected by satellites, field measurements, and ecosystem modelling, and integrating this method as part of field carbon balance calculators. Participants in the Biohila project are the Finnish Meteorological Institute, Häme University of Applied Sciences, Biocode, Valio, and Natural Resources Institute Finland

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