EGU General Assembly 2020
© Author(s) 2020. This work is distributed under
the Creative Commons Attribution 4.0 License.

Short-term effects of biochar on soil CO2 efflux in boreal Scots pine forests

Xudan Zhu
Xudan Zhu
  • University of Eastern Finland, Faculty of Science and Forestry, Department of Environment and Biological Science, Joensuu, Finland (

The use of biochar as a soil amendment has been proposed to increase the carbon (C) sequestration in soils. However, a more rapid soil organic matter turnover after biochar application might reduce the effectiveness of biochar applications for C sequestration. Data on the effects of biochar on soil C turnover is particularly important in boreal forests where large quantities of forest harvest residues would be available as feedstock for biochar production. To better understand the effects of biochar on boreal forest soil, we established a split-plot experiment where two spruce biochar produced with different temperatures (500°C and 650°C) were applied at a rate of 1.0 kg m-2 and 0.5 kg m-2 in a young xeric Scots pine forest in southern Finland. Measurement of soil CO2 effluxes and microbial biomass were used to investigate changes in soil C dynamics. Biochar application increased the rate of soil CO2 efflux by 10.6% across all biochar treatments and significantly (P<0.05) in 1.0 kg m-2 treatments. Soil microbial biomass remained unchanged. Soil temperature was 0.1 to 0.5°C higher in the biochar-amended treatments. Further analysis revealed that when soil CO2 efflux was corrected for the changes in soil temperature and soil moisture, there were no significant differences between treatments. We conclude that increase in soil CO2 efflux was attributed to warmer soils at the initial stage after biochar application to the soil surface; changes in soil chemical properties did not have any detectable effect on soil respiration.

How to cite: Zhu, X.: Short-term effects of biochar on soil CO2 efflux in boreal Scots pine forests, EGU General Assembly 2020, Online, 4–8 May 2020, EGU2020-21914,, 2020


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