Charcoal and biochar addition to tropical soils has been shown to improve crop yields, sometimes dramatically. In more fertile soils, or in soils that receive high levels of external inputs, and are not liable to water-stress, the corresponding impacts of biochar (and charcoal) on agronomic performance have yet to be demonstrated. Emerging evidence from field trials using charcoal in the UK, and other temperate countries, indicates a modest benefit to the limited number arable systems tested so far.

The Australia-based environmental consultancy E3 International have published a report of and presentations from a workshop they held recently on soil carbon sequestration. The presentations and discussions covered the following issues: Potential of soil carbon and factors impacting on soil carbon The extent of our understanding of the potential to increase soil carbon under different practices, and sequestration rates; consideration of the role of other nutrients and water as well as the role of innovation and new technologies

The FAO has produced a new review of the potential for dryland pastoral systems to adapt to and mitigate climate change through soil carbon sequestration: "Review of evidence on drylands pastoral systems and climate change Implications and opportunities for mitigation and adaptation." Land and water discussion paper 8, FAO, 2010.