Fertilizer-Controlled Yield Meta-analysis
Citation: Ye L, Camps-Arbestain M, Shen Q, Lehmann J, Singh B, Sabir M (2020). Biochar effects on crop yields with and without fertilizer: A meta-analysis of field studies using separate controls. Soil Use and Management 36(1): 2–18 (online December 2019). https://doi.org/10.1111/sum.12546 · author-hosted PDF
What it is: A meta-analysis of field studies that compares biochar against separate fertilized and unfertilized controls, so biochar’s effect isn’t confused with the fertilizer’s. It’s the vault’s reference for the right comparison when biochar goes on with fertilizer.
Key figures
| Figure | Value | Where | Check |
|---|---|---|---|
| Biochar + inorganic fertilizer vs fertilizer alone | +15% yield (CI 11–19%) | Abstract (author PDF) | ✓ full text |
| Fertilizer alone vs unfertilized control | +26% (CI 15–40%) | Abstract | ✓ full text |
| Biochar + fertilizer vs unfertilized control | +48% (CI 30–70%) | Abstract | ✓ full text |
| Biochar alone | Did not increase yield, whichever control was used | Abstract | ✓ full text |
| Application rate | Rates above 10 t ha⁻¹ added no yield, at least in the short term; 5–10 t ha⁻¹ out-yielded 10–20 t ha⁻¹ against fertilized controls | Results and conclusions | ✓ full text |
| Soil pH | Biochar shouldn’t be applied to high-pH soils | Conclusions | ✓ full text |
| Largest responses | Sandy and low-CEC soils | Results | ✓ full text |
Use with care
- DOI correction: Key Sources listed this paper as 10.1111/sum.12555, which is a different article. The correct DOI is 10.1111/sum.12546.
- The +15% is biochar’s added effect on top of fertilizer. It doesn’t apply to biochar used instead of fertilizer.
Related: Crop Yield Effects · reviews biochar climate mitigation · meta-analyzes biochar fertilizers · Key Sources