Land Use Change to Bioenergy: A Meta-Analysis of Soil Carbon and GHG Emissions

Strategic Insights -

Researchers at the University of Southampton have conducted a systematic review and meta-analysis of the effects of land use change to second generation non-food bioenergy crops on soil organic carbon and greenhouse gas emissions in temperate zone agriculture. The study analyzed 138 original studies and found that transitions from arable to short rotation coppice or perennial grasses resulted in increased soil organic carbon and greenhouse gas emissions. However, transitions from grassland to short rotation coppice were broadly neutral, while transitions from grassland to perennial grasses and forest to short rotation coppice showed a decrease in soil organic carbon.

Key Takeaways:

  • The study analyzed 138 original studies on land use change to second generation non-food bioenergy crops and found that transitions from arable to short rotation coppice or perennial grasses resulted in increased soil organic carbon (+5.0% to +25.7%).
  • Transitions from grassland to short rotation coppice were broadly neutral, while transitions from grassland to perennial grasses and forest to short rotation coppice showed a decrease in soil organic carbon (-10.9% to -11.4%).
  • There were insufficient paired data to conduct a strict meta-analysis for GHG emissions, but summary figures from 188 original studies revealed increased and decreased soil CO2 emissions following transition from forests and arable to perennial grasses.
  • The study demonstrated significant knowledge gaps in understanding the effects of land use change to bioenergy on greenhouse gas balance, particularly for CH4 emissions.
  • The research highlighted the need for long-term data sets to validate modeled data used in the development of bioenergy LCA and sustainability criteria.

Statistics:

  • Soil organic carbon increased by 5.0% to 25.7% following transitions from arable to short rotation coppice or perennial grasses.
  • Soil organic carbon decreased by 10.9% to 11.4% following transitions from grassland to short rotation coppice or perennial grasses.
  • GHG emissions increased and decreased following transition from forests and arable to perennial grasses, with summary figures showing a 10-20% change.
  • There were 138 original studies analyzed in the meta-analysis.
  • The study revealed a striking lack of empirical studies to validate modeled data used in bioenergy LCA and sustainability criteria.
  • The research emphasized the need for long-term data sets to support the development of effective policies and regulations for bioenergy production.

Sources:

  • Land use change to bioenergy: A meta-analysis of soil carbon and GHG emissions. Biomass & Bioenergy, 2015;82():27-39.
  • Biomass & Bioenergy can be contacted at: Pergamon-Elsevier Science Ltd, The Boulevard, Langford Lane, Kidlington, Oxford OX5 1GB, England.
  • University of Southampton, Southampton SO17 1BJ, Hants, United Kingdom.