Microbial Inocula Meta-analysis
Citation: Ross AT, Emery SM (2025). Microbial inocula enhance effects of biochar amendments on crop productivity, soil health, and microbial communities: A meta-analysis. Soil Science Society of America Journal 89(1): e20792 (online 5 Dec 2024). https://doi.org/10.1002/saj2.20792
What it is: The meta-analysis behind the vault’s claim that adding microbial inocula to biochar helps on average, but mainly with local or research-grade inocula and mainly in greenhouse studies.
Key figures
| Figure | Value | Where | Check |
|---|---|---|---|
| Studies | 56 | Abstract | ✓ abstract |
| Biochar + inoculum vs biochar alone | Higher soil N, soil organic carbon, and crop productivity | Abstract | ✓ abstract |
| Inoculum source | Gains limited to locally sourced and research-grade inocula; commercial products only slightly raised soil P | Abstract | ✓ abstract |
| Inoculum type | Fungal inocula stronger than bacterial | Abstract | ✓ abstract |
| Experiment type | Strongest in greenhouse studies (N, productivity, fungal abundance); field studies raised only plant productivity | Abstract | ✓ abstract |
| Authors’ conclusion | Activating biochar with inocula on farms may not deliver the intended benefits; other activation methods may be needed | Abstract | ✓ abstract |
Use with care
- The effect sizes are in the full paper, which wasn’t re-checked. Quote directions of effect from this note, not magnitudes.
- The first author’s surname is Ross (given names Aysha Tapp); some vault notes cite “Tapp Ross”.
Related: Biochar Microbes and Soil Biology · Biochar Inoculation for Fertilizer · Key Sources