Steffanie Schirren
Institute of Climate-Smart Agriculture

Bundesallee 65
38116 Braunschweig
Phone: +49 531 596 2602
Fax: +49 531 596 2699

Land use change on thawing permafrost soils


 (c) Thünen-Institut/AK

Breaking the Ice – Consequences of northwards extending agriculture for soil organic matter cycling under a changing climate

What happens when permafrost soils under boreal forest are changed into arable land or grassland? Will cultivation accelerate thawing and thereby microbial activity? How will agricultural practices, such as ploughing, fertilization, crop rotation change microbial communities and their sensitivity to global warming? These questions shall be answered in this project.

Background and Objective

The earth is warming and human population is growing. It is thus likely, that thawing permafrost soils under natural vegetation will be cultivated in the near future.  It is however completely unknown, how this will affect soil organic matter cycling in these soils. It is also not understood, how cultivation of such nutrient poor natural soils will change the temperature sensitivity of organic matter decomposition under ongoing climate change. Such knowledge is however crucial for predicting CO2 fluxes between atmosphere and biosphere. Therefore the project aims to evaluate:

  • Soil organic carbon stock changes after land-use change on frozen and unfrozen soils as a function of time.
  • Changes in soil temperature, active layer depth and potential litter decomposition upon land-use change
  • Evaluate changes in microbial carbon use efficiency, community composition and temperature sensitivity of microbial activity


The Yukon Territory in Northwest Canada has a more than 100 years old history of land-use changes on cold soils. This is unique and provides the opportunity to study soil organic matter dynamics after land-use change as a function of time in a chronosequential approach. An additional thermosequence exists via the temperature gradient from south (mostly permafrost-free soils) to the north (mostly permafrost soils) of the Yukon Territory. Microbial processes will be quantified in incubation experiments and results will be implemented in turnover models.


Involved Thünen-Partners

Involved external Thünen-Partners

  • Agriculture and Agri-Food Canada
    (Ottawa, Kanada)

Funding Body

  • Deutsche Forschungsgemeinschaft (DFG)
    (national, öffentlich)


1.2019 - 12.2021

More Information

Projekt type:
Project status: ongoing