Biochar Lab Measurement Standard
Citation: ANSI/ASABE/USBI S668 NOV2025ED. Methods for Measurement and Testing of Biochar. Published by ASABE November 2025. PDF via American Biochar Institute: https://biochar.org/wp-content/uploads/2026/05/ANSI-S668.pdf · document page: https://biochar.org/document/ansi-s668/
What it is: American National Standard listing recommended test methods for biochar materials (sampling, proximate/ultimate analysis, calorimetry, permanence assessment methods, physical properties, surface area/porosity, environmental contaminants including PAHs/PCBs/dioxins/PFAS/heavy metals, and agricultural parameters such as nutrients, pH, liming potential, and salinity). Front matter frames ASABE standards as informational/advisory and voluntary.
Key figures
| Figure | Value | Where | Check |
|---|---|---|---|
| Designation | ANSI/ASABE/USBI S668 NOV2025ED | Cover / title block — PDF | ✓ full text |
| Scope (contaminants) | Includes PAHs, PCBs, dioxins, PFAS, heavy metals | Scope section — PDF · doc page | ✓ full text |
| Scope (ag parameters) | Nutrient content, pH, liming potential, salinity | Same | ✓ full text |
| Role | Test methods, not a carbon-credit methodology or farm practice standard | ASABE front matter + ABI doc blurb | ✓ full text |
Use with care
- Does not replace defines NRCS practice 336 eligibility tables or registry MRV rules.
- Pair with Product Standards EBC IBI (product classes), Contaminants and Quality, and practice chapter Testing EBC IBI S668. Permanence method section links H-Corg and O-Corg · Reflectance Ro and HyPy.
Related: US Biochar Initiative · USBI Guidance vs Vault Notes · Product Standards EBC IBI · Testing EBC IBI S668 · Key Sources