Biochar is created by pyrolyzing biomass under low oxygen. Higher pyrolysis temperatures produce more aromatic, recalcitrant carbon that resists microbial decomposition, locking atmospheric CO2 into soil for centuries.
C_stable(t) = C0 · f_stable · e^(−t / τ)
f_stable ≈ 0.4 + 0.006·(T − 300) [fraction, T in °C]
τ (mean residence time) grows with T
- Pyrolysis temperature — controls aromaticity and the stable-carbon fraction of the biochar.
- Application rate — tonnes of biochar added per hectare, sets total carbon input.
- Soil moisture — affects microbial activity and pore water retention, shown by the blue water table.
- Years elapsed — advances decomposition of the labile (fast-decaying) fraction, leaving the stable core; Play years animates this automatically.
Real-world application: biochar soil amendment is used in regenerative agriculture as a verified carbon-removal credit method, while also improving water retention and cation exchange capacity.