Institute of

Climate-Smart Agriculture

Soil organic carbon

Preserving soil organic matter and mitigating climate change

Sampling of a 120 cm deep ploughed forest soil close to Gifhorn, Northern Germany
Sampling of a 120 cm deep ploughed forest soil close to Gifhorn, Northern Germany (© Thünen-Institut/Axel Don)

Soil organic matter is not only a crucial factor for soil fertility but also important in light of climate change. When soil organic matter is lost by management the greenhouse gas carbon dioxide (CO2) is released. Soils can also accumulate soil organic matter and thus sequester CO2-carbon. When nitrogen bound in soil organic matter is mineralized the loss of soil organic matter stocks can also lead to nitrous oxide (N2O) emissions.

We measure, analyze and model the formation and turnover processes of organic matter in agricultural soils together with the reaction pathways of carbon and nitrogen. We evaluate by approaches stratified by soil and climate conditions how agricultural soil use and targeted management measures affect soil organic matter.

Our research acitivities focus on

  • the turnover processes and the significant losses of soil organic matter from drained peatlands used for agriculture,
  • the assessment of land-use changes interacting with soil and climate conditions,
  • the importance of subsoil for the stabilization and sequestration of soil organic matter
A gleysoil under cropland shows the typical distinct lower boundary of the plough horizon (National Agricultural Soil Survey)
A gleysoil under cropland shows the typical distinct lower boundary of the plough horizon (National Agricultural Soil Survey) (© Thünen-Institut/AK)

We conduct the first National Agricultural Soil Survey to quantify soil organic carbon in more than 3,000 sites across Germany. We thus create a new empirical data basis to assess the impact of climate, soil properties, land-use and management on soil organic matter stocks and the amount of carbon and nitrogen stored therein. We also test the potential and risks associated with the application of diverse types of biochars for enhancing soil fertility and soil organic carbon stocks in agricultural soils.