Stability and Priming Meta-analysis
Citation: Wang J, Xiong Z, Kuzyakov Y (2016). Biochar stability in soil: meta-analysis of decomposition and priming effects. GCB Bioenergy 8(3): 512–523 (online 2015). https://doi.org/10.1111/gcbb.12266 (open access)
What it is: Two meta-analyses in one paper. The first asks how fast biochar itself decomposes, using isotope-labelled studies. The second asks whether biochar speeds up or slows down decomposition of native soil organic matter (“priming”).
Key figures
| Figure | Value | Where | Check |
|---|---|---|---|
| Decomposition dataset | 128 observations from 24 ¹³C/¹⁴C studies | Abstract | ✓ abstract |
| Biochar carbon pools | Labile ~3% (mean residence ~108 days); recalcitrant ~97% (mean residence ~556 years) | Abstract | ✓ abstract |
| Priming dataset | 116 observations from 21 studies | Abstract | ✓ abstract |
| Overall priming | Soil organic matter mineralization −3.8% (95% CI −8.1% to +0.8%): a slight slowdown whose interval includes zero | Abstract | ✓ abstract |
| Significant negative priming | Studies shorter than half a year −8.6%; crop-derived biochar −20.3%; fast pyrolysis −18.9%; lowest pyrolysis temperature −18.5%; small application amounts −11.9% | Abstract | ✓ abstract |
| Positive priming | Sandy soils: soil organic matter mineralization +20.8% | Abstract | ✓ abstract |
| Conclusion | Biochar persists on a centennial scale | Abstract | ✓ abstract |
Use with care
- Correction to earlier vault notes: several notes cited this paper for “short-term positive priming is common”. For short studies it found the opposite: significant negative priming under six months. Its positive priming was in sandy soils, and the overall −3.8% isn’t statistically different from zero.
- Decade-scale field evidence of negative priming comes from other work, such as Weng et al. 2017 (https://doi.org/10.1038/nclimate3276).
Related: Permanence · GHG Fluxes · Biochar Microbes and Soil Biology · Key Sources