Carbon accounting: how a spreadsheet helps in the fight against climate change

Carbon accounting: how a spreadsheet helps in the fight against climate change

In the "Carbon Farmers" project, Lidl, Boerenbond, Boerennatuur, the Soil Service of Belgium and Rikolto support nine Belgian farmers to store more carbon in their soil. But how do you measure that? Enter: carbon accounting. Mieke Verbeeck from the Soil Service of Belgium visited the participating farmers over the past months to establish this accounting.

"With our carbon accounting, we estimate how much CO2 can be sequestered in the soil and potentially in woody biomass," explains Mieke Verbeeck. "For the farms in the project, we will examine how the soil management of the farm translates into CO2 emissions, but also how much CO2 they are capturing in their soils."

The accounting focuses on organic carbon and CO2, but also on nitrous oxide emissions linked to soil management. "Carbon is continuously being built up and broken down in the soil," Verbeeck explains. "We estimate the input of carbon that takes place through crop residues from main crops, cover crops, and fertilisation," she clarifies.

"In addition, we take into account CO2 emissions associated with the breakdown of carbon and the use of nitrogen fertilisers and lime-a product that farmers use to improve the soil's acidity." Nitrous oxide, a potent greenhouse gas, receives special attention. "It is released during the breakdown of organic matter, during fertilisation, and through the use of nitrogen fertilisers," says Verbeeck. "By monitoring these sources, farmers can take targeted action."

From accounting to action

The carbon accounting is tracked in a detailed Excel sheet. "We collect annual data on fertiliser use, crops grown, the percentage of fields with cover crops and more." This tool allows farmers to adjust the impact of their soil management. "They can better estimate what certain measures actually achieve," explains Verbeeck. "Lidl, on the other hand, can assess which measures among farmers reduce emissions in their supply chain the most. They can then support these practices among the farmers who supply them."