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

Xudan Zhu, Tingting Zhu, Jukka Pumpanen, Marjo Palviainen, Xuan Zhou, Liisa Kulmala, Viktor Bruckman, Egle Köster, Kajar Köster, Heidi Aaltonen, Naoki Makita, Yixiang Wang, Frank Berninger

Research output: Contribution to journalArticleScientificpeer-review


Key message During the first summer, wood biochar amendments increased soil temperature, pH, and soil CO(2)effluxes in a xeric boreal Scots pine forest. The increase of soil CO(2)efflux could be largely explained by increases in by soil temperature. Higher biochar application rates (1.0 vs 0.5 kg m(-2)) led to higher soil CO(2)efflux while the pyrolysis temperature of biochar (500 or 650 degrees C) had no effect on soil CO(2)efflux. Context Using biochar as a soil amendment has been proposed to increase the carbon sequestration in soils. However, a more rapid soil organic matter turnover after biochar application might reduce the effectiveness of biochar applications for carbon sequestration. By raising the pyrolysis temperature, biochar with lower contents of labile carbohydrates can be produced. Aims To better understand the effects of biochar on boreal forest soil, we applied two spruce biochar with different pyrolysis temperatures (500 degrees C and 650 degrees C) at amounts of 1.0 and 0.5 kg m(-2)in a young xeric Scots pine forest in southern Finland. Methods Soil CO2, microbial biomass, and physiochemical properties were measured to track changes after biochar application during the first summer. Results Soil CO(2)increased 14.3% in 1.0 kg m(-2)treatments and 4.6% in 0.5 kg m(-2). Soil temperature and pH were obviously higher in the 1.0 kg m(-2)treatments. Differences in soil CO(2)among treatments disappear after correcting by soil temperature and soil moisture. Conclusion Biochar increased soil CO(2)mainly by raising soil temperature in the short term. Higher biochar application rates led to higher soil CO(2)effluxes. The increase in soil CO(2)efflux may be transient. More studies are needed to get the optimum biochar amount for carbon sequestration in boreal forest.

Original languageEnglish
Article number59
JournalAnnals of Forest Science
Issue number2
Number of pages15
Publication statusPublished - 15 Jun 2020
MoE publication typeA1 Journal article-refereed

Fields of Science

  • 1172 Environmental sciences
  • Biochar
  • Boreal forest
  • Soil temperature
  • Soil CO2
  • Soil microbial biomass
  • 4112 Forestry
  • Biochar
  • Soil microbial biomass
  • Soil CO2
  • Soil temperature
  • Boreal forest

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