Published 2018-06-26

This post is also available in Swedish

More carbon in arable land boosts biological activity

Capturing more carbon in vegetation and land is a goal strongly supported by research. It could yield bigger harvests, improve soil structure and boost biological activity, while also slowing the global temperature rise.
How to achieve the raised rate of capture and storage in practice was recently discussed at a seminar held by Mistra EviEM.

Why should we care about carbon in the ground? This was the initial rhetorical question from moderator Peter Sylwan when Mistra’s Council for Evidence-Based Environmental Management (Mistra EviEM) organised a seminar on how arable land can help capture more carbon dioxide.

Sylwan himself answered: carbon is the basis of all life.

However, to narrow down the issue somewhat, the seminar focused on how increased carbon capture from the atmosphere could help to slow global warming. A higher humus content also has positive effects on harvests, for reasons including better soil structure, increased infiltration, improved retention of nutrients and water, and greater biological activity.

The global ‘4 per 1000’ initiative’ (endorsed by Sweden, for example) is also aimed at increasing carbon sequestration in agricultural land. The name refers to the fact that, with a rise in soil carbon of 0.4 per cent a year, all carbon dioxide emissions from fossil sources could be sequestered. For the same reason, the Cross-Party Committee on Environmental Objectives has raised the need for increased carbon sequestration in its strategy on climate and clean air.

Measures to help us get there include reduced tillage, perennial grassland and increased use of catch crops.

During the seminar, the status of knowledge about sequestration of organic carbon in farmland was also presented. The results are from a systematic survey based on 735 field trials, and also findings from ongoing Swedish research. The report is available on Mistra EviEM’s website; see below.

Håkan Wallander, Professor at Lund University, stated in an introductory address that how we farm is of great importance. If we do it right, the volume of carbon captured increases. If we get it wrong, the carbon is released to the atmosphere instead. One of his many recommendations was to focus on perennial crops.

‘If we could switch to perennial wheat varieties, it would automatically mean that we sequester more carbon in the soil, while reducing nutrient leaching.’

How this new knowledge can be used in the design of new policy instruments, for example in the EU’s Common Agricultural Policy (CAP), was also discussed.

Gustaf Ramel of Gårdstånga Nygård showed how this can be done in practice. This farm is unique in having belonged to his family for more than 400 years, but also because ploughing the soil stopped there more than ten years ago. According to him, this has brought about farming that sequesters more carbon in the soil, cuts costs and boosts harvests.

‘I started using this cultivation method to save money, and then we discovered that it’s also good for the environment,’ Ramel concluded.

The other speakers during the day were Katarina Hedlund, Professor at Lund University; Katharina Meurer, a postdoctoral researcher at the Swedish University of Agricultural Sciences (SLU); Thomas Kätterer, Professor at SLU; Neal Haddaway of Mistra EviEM; and Per Bodin, Environmental Objectives Coordinator at the Swedish Board of Agriculture. The day ended with seminar attendees and invited speakers discussing solutions and remaining questions. Everything was filmed and can be watched online; see the link below.

The seminar was organised by Mistra EviEM in cooperation with the Royal Swedish Academy of Agriculture and Forestry (KSLA), the Swedish Board of Agriculture, Lund University and SLU.

Links

More material, filmed lectures and presentations (in Swedish): here.

Mistra EviEM’s website