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Plantekongres 2022: Plant residues as a source of nitrous oxide

Plant residues are one of the sources of nitrous oxide in agriculture, in fact they account for approx. 10% of the total emission of nitrous oxide from Danish agriculture. At this year's virtual Plantekongres, you have the opportunity to become wiser about the importance of plant residues and nitrous oxide emissions. Results from the project ResidueGas show, that there is a big difference between different types of plant residues.

At this year's virtual Plantekonrgres, you have the opportunity to learn more about about the importance of cover crops for nitrous oxide emissions. Photo: Henning Carlo Thomsen

Nitrous oxide, which is a very potent greenhouse gas, plays a major role in the overall climate footprint of Danish agriculture. At a webinar at Plantekongres 2022, professor and head of department Jørgen E. Olesen from the Department of Agroecology will talk about how plant residues can affect the emission of nitrous oxide.

“Nitrous oxide from plant residues is currently calculated as one percent of the amount of nitrogen returned to the soil from plant residues. However, there is good evidence that there is a very large difference in the amount of nitrous oxide emissions from different types of plant residues,” says Jørgen E. Olesen.

In the webinar, he will talk about the ResidueGas project, where different types of plant residues has been investigated and how they can affect nitrous oxide emissions differently based on both published studies and new trials.

Very big difference

In the ResidueGas project, the researchers found that there is a very large difference between ripe or unripe plant remains. Ripe plant remains such as straw has a low nitrogen content and they are slowly metabolized in the soil. Unripe plant remains, on the other hand, are green plants such as vegetables, grass or catch crops. These plant residues typically have a high nitrogen content and contain organic matter that is easy to metabolize. In other words, they are rapidly degraded by the earth's microorganisms.

“Our analyzes show that there are very low emissions of nitrous oxide from ripe plant residues, while emissions from unripe plant residues are high. This means that there must be a particular focus on minimizing nitrous oxide from mulching vegetable residues, catch crops and grasslands. This can be done, for example via harvest or simply by removing the plant remains,” explains Jørgen E. Olesen.

At the webinar on Tuesday 18 January at 10.15-11.00 he will talk more about the possibilities and complications of plant residues from catch crops to reduce nitrous oxide emissions in Danish agriculture, just as he will also talk about the results from the ResidueGas project. 

Virtual Plant Congress

This webinar is part of the Plantekongres 2022. Again this year, the Plantekongres is being held virtually due to the Covid-19 pandemic. But the content is still the same, now you can instead follow the many exciting presentations at home from the living room when they are held as webinars. In addition to this webinar, you can hear about:

  • Resistant grass weeds - Resistant grass weeds are a persistent challenge in grain-rich crop rotations. The problem is growing, because more resistant species are coming at the same time as we have fewer control options. How will this challenge be handled in the future? The webinar will be held on Thursday 13 January at 10.15 - 11.00.
  • Carbon build-up in soil and documentation - Carbon as an indicator of healthy soil is framed in relation to the EU CAP reform - new green deal etc. Standardized methods for documenting Carbon Farming are fundamental for trading in CO2 credits. The methods combine carbon measurements in soil, data from satellites and drones, climate and cultivation history as well as modeling. Hear about the MRV concept's application in a Danish context. The webinar will be held on Thursday 13 January at 11.15 - 12.00.
  • Climate-friendly roughage production - Grass has a positive climate profile, but how is a large emission of nitrous oxide and nitrate avoided by conversion? Also hear about the interaction between what happens in the animals and the climate effect in the field when growing there, which is best to reduce methane from the cows. The webinar will be held on Thursday 13 January 2022 at 15.15 - 16.00

Read more about Plantekongres 2022 here www.plantekongres.dk (in Danish)

Additional information


Professor and Head of Department Jørgen E. Olesen, Department of Agroecology, Aarhus University. Tel. +45 48821659 or mail: jeo@agro.au.dk