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Division of Food Production and Society

CAPTURE - Assessment of cover cropping as climate action in cereal production in Norway

Photo: Anne Kjersti Bakken
Active Last updated: 10.10.2023
End: feb 2025
Start: mar 2021

The aim of CAPTURE is to document the climate effect of using cover crops in cereal production in Norway, as well as to develop well-functioning cultivation strategies. 


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Start - end date 01.03.2021 - 28.02.2025
Project manager Randi Berland Frøseth
Division Division of Food Production and Society
Department Grain and Forage Seed Agronomy
Partners NMBU, NORSØK, HINN, SLU, NLR, Yara Norge AS and Strand Unikorn AS
Total budget 12 756 000 NOK
Funding source Agriculture and Food Industry Research Funds and County Governor of Trøndelag

Cover crops are grown to keep the soil covered with plants after harvest of the main crop. In Norway, cover crops were introduced in the 1990’s to prevent loss of nitrogen and phosphorous from fields to waterways.Cover crops contribute with several ecosystem services and are considered an applicable climate action. However, it can currently not be posted in the greenhouse gas accounts for the agricultural sector in Norway because of insufficient documentation of its effect under our conditions. 

The climate effect in this context is the ability cover crops have to sequester carbon weighed against both nitrate leaching and nitrous oxide emissions from decomposing plant residues in the soil. In a field trial, selected cover crop species will be marked with the carbon isotope C-13 to follow the flow of carbon to soil and its distribution in organic matter fractions. Together with data on biomass production under real farming conditions, this will provide input to a model for predicting long-term trends of carbon sequestration in accordance with the UN Climate Panel's methodology. The ability of different cover crop species to preserve nitrogen and avoid risk of direct and indirect nitrous oxide emissions will also be documented in field trials. Fertilization of cover crops will be included as a treatment in the experiment. 

An on-farm survey will provide data on cultivation practices and the amount and variation in biomass of cover crops in Southeast- and Mid Norway. In addition, experiments in the cereal production regions will provide more knowledge about species and cultivation methods that minimize potential trade-offs and optimize the overall effect of cover cropping. 

Publications in the project

To document


In Norway, cover crops were introduced to prevent loss of nitrogen and phosphorous from fields to waterways. Today, cover crops are also used to restore soil organic matter and improve soil health. Yet, the direction and magnitude of these effects are variable, and little is known about the persistence of the C derived from the cover crops in the soil. In the CAPTURE project, we evaluated the soil C sequestration potential from different cover crops used in the main cereal production areas in Norway. To do so, we used pulse labelling with 13C (CO2) to label four different cover crop species Italian ryegrass, phacelia, oilseed radish and summer vetch through their growing period. Cover crops were grown in a monoculture to enable the labelling. The results of the first year of the experiment show that cover crops produced 10- 14 Mg ha-1 above ground biomass, corresponding to 4-6 Mg C ha-1. At the end of the growing season, 3-5% of cover crop C was found in the soil particulate organic matter (POM) fraction and 2-4% in the soil mineral organic matter fraction (MAOM). In the following years, the fate of C derived from the cover crops in the soil will be determined. Furthermore, the soil C sequestration of the different cover crops will be scaled to barley plots in the same experiment, to which cover crops had been undersown in spring or summer. In these plots, N2O emissions have been measured through the whole year. The greenhouse gas trade-offs of cover crops in Norwegian cereal production will be estimated.

To document


Enhancing carbon storage in managed soils through increased use of cover and catch crops in cereal cropping is at the heart of a carbon-negative agriculture. However, increased C storage by additional biomass production has a nitrogen cost, both in form of increased N fertilizer use and by potentially increasing nitrous oxide (N2O) emissions when cover crops decay. Frost-sensitive, N-rich aboveground biomass may be a particular problem during wintertime, as it may fuel off season N2O emissions during freezing-thawing cycles, which have been shown to dominate the annual N2O budget of many temperate and boreal sites. Here we report growing season and winter N2O emissions in a plot experiment in SE Norway, testing a barley production system with seven different catch and cover crops (perennial and Italian ryegrass, oilseed radish, summer and winter vetch, phacelia and an herb mixture) against a control without cover crops. Cover crops where either undersown in spring or established after harvesting barley. While ryegrass undersown to barley marginally reduced N2O emissions during the growing season, freeze-thaw cycles in winter resulted in significantly larger N2O emissions in treatments with N-rich cover crops (oilseed reddish, vetch) and Italian ryegrass. N2O budgets will be presented relative to aboveground yield and quality of cover crops and compared to potential souil organic carbon gains.