Page 43 - Green knowledge 2023

Photo: Siri Svendgård-Stokke
More roots for more sustainable agriculture
Growing plants for food production generally leads to a net loss of carbon from soil in the form of carbon dioxide, which is the greenhouse gas contributing most to climate warming. Now, researchers are investigating what it takes for more carbon to remain in agricultural soils.
For a long time, the aim of plant breeding was to provide highest possible yields. Much of the roots were bred away because the plants did not require as many when supplied with nutrients from artificial fertilisers. As it turns out, smaller root systems can have negative consequences for the climate.
In 2005, a group of researchers discovered that carbon from roots remains in the soil for a longer time than originating from above-ground plant residues.
“We examined a whole range of studies that com- pared the ability of roots and shoots to store carbon in the soil,” says Dr Daniel Rasse. “We found that carbon originating from roots, on average, remains in the soil more than twice as long as carbon from shoots.”
There are several reasons for this. Roots break down more slowly due to substances resistant to decompo- sition. Additionally, root material adheres better to
mineral particles in the soil, protecting against microbial breakdown.
NIBIO has several on-going several research projects investigating the size of root systems in field crops and how this affects carbon sequestration in Norwe- gian agricultural soil. One of these is the European project MaxRoot C, where NIBIO examines the root systems of 13 wheat varieties.
“Our field is the northernmost in the project. We investigate the size and depth of the root systems of the wheat varieties and how well the varieties are adapted to Norwegian conditions. The goal is to find varieties with larger root systems without compro- mising aboveground yields,” says Dr Teresa Gómez de la Bárcena.
More knowledge about the ability of root systems to store carbon in the soil is a significant contribution to a more climate-smart Norwegian agriculture.
Purpose: Investigate how the root systems of field crops and catch crops affect carbon sequestration and carbon supply in Norwegian agricultural soil.
Contact: Head of Department/Head of Research Daniel Rasse. Email: daniel.rasse@nibio.no, phone: (+47) 922 63 608. Division of Environment and Natural Resources
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