Biochar made by clean pyrolysis of crop, forestry and processing residues — used as a soil amendment and sold as durable carbon removal — instead of open burning, dumping or landfilling of those residues

Replaces: open burning and dumping of residues · Scope: agriculture and carbon removal · Evidence: high (carbon persistence, tropical soils), medium (fertile temperate soils)

The chemical problem#

• Large volumes of straw, husks, shells and prunings are burned or dumped each year (see WC01), releasing smoke and greenhouse gases.
• Soils in much of the tropics are acidic and low in organic matter; lime and fertilizer are the default fixes.
• Carbon-removal buyers need durable removals; biochar is one of the few already sold at volume.

Product overview#

1. Pyrolysis biochar — biomass heated to roughly 400–700 °C with little oxygen; the gases are burned for heat or power.
2. Uses in agriculture — soil amendment (often co-composted or nutrient-charged first), growing-media component (CE01), carrier for microbial inoculants.
3. Carbon-removal credits — certified biochar removals sold on voluntary markets, adding income to the plant.
4. Feedstocks — rice husk, straw, coconut and nut shells, palm residues (EFB), sawmill residues, prunings; avoid contaminated feedstocks.

Active ingredient / Composition#

• Stable aromatic carbon (typically >50 % C, often >70 %), ash minerals (K, Ca, Mg, P), high porosity and surface area; properties depend on feedstock and temperature.

Key facts#

Advantages#

• Ends burning or dumping of the residue and stores carbon durably.
• Liming effect and better water and nutrient retention on poor soils.
• Two revenue streams: biochar product + carbon-removal credits.
• Local production with small to medium kilns (EQ03).

Mode of action#

• Pyrolysis converts labile biomass carbon into condensed aromatic carbon that microbes decompose very slowly.
• In soil, biochar raises pH, cation-exchange capacity and water holding, and gives microbes a habitat; charged biochar also carries nutrients.

Application#

Limitations#

• Soil response is variable — little benefit on fertile soils; raw biochar can temporarily tie up nutrients.
• Feedstock must be clean (no treated wood, plastics, heavy metals); PAH and dioxin limits apply.
• Dirty kilns cancel the climate benefit.
• Carbon-credit prices and methodologies are still evolving.

Evidence of displacement — D1: works, adoption not proven#

Verified figures (the number is in the quoted sentence and the sentence is on the source page):

• performance — In an on-farm study in India, biochar application resulted in a 4.34% increase in crop yield, a 29.34% increase in net return, and a 1.52% reduction in the cost of cultivation. (India, 2026; peer-reviewed: exa.ai)
• performance — Co-incorporation of mung bean residue and rice husk biochar allowed for a 30% reduction in nitrogen and 50% reduction in phosphorus and potassium fertilizer applications without compromising rice yield in a Vietnam field study. (Vietnam, 2025; peer-reviewed: mdpi.com)
• performance — Biochar production is growing rapidly, with a global production of at least 350,000 metric tonnes in 2023, representing a 91% CAGR over 2021. (global, 2023; weak: biochar-international.org)
• performance — Global biochar production increased from 180,150 metric tonnes in 2023 to 520,810 metric tonnes in 2025. (global, 2023-2025; weak: biochar-international.org)

Suppliers — real products and services (from the vendor index)#

Active vendors whose own card shows biochar production or biochar carbon-removal projects. Charcoal makers for fuel are not cited.

Government funding signals#

Scanned 2026-10-02 (OpenAIRE + NSF + USDA); candidates reviewed by hand.

Signal: Strong. 65 candidates, including EC 101182442 (modular biochar and board production plants, €5.0 M, 2025), ARC Linkage LP120200645 (urban biochar, AUD 405 k), FWF I 3133 (biochar and conazole fungicides in soil) and Czech TA ČR projects on practical biochar application to soils and substrates (TJ01000071).

Scientific evidence#

• Woolf D, Amonette JE, Street-Perrott FA, Lehmann J, Joseph S (2010). Sustainable biochar to mitigate global climate change. Nature Communications 1: 56.
• Jeffery S, Verheijen FGA, van der Velde M, Bastos AC (2011). A quantitative review of the effects of biochar application to soils on crop productivity using meta-analysis. Agriculture, Ecosystems & Environment 144: 175–187.
• Schmidt HP, Kammann C, Hagemann N, et al. (2021). Biochar in agriculture – a systematic review of 26 global meta-analyses. GCB Bioenergy 13: 1708–1730.
• Lehmann J, Cowie A, Masiello CA, et al. (2021). Biochar in climate change mitigation. Nature Geoscience 14: 883–892.

Bioeconomy value#

Biochar pays twice, as a soil product and as a carbon-removal credit, and it closes the residue-burning problem.

First article of carbon removal (2026-10-02). Cross-links: WC01 residue burning; EQ03 pyrolysis kilns; CE01 growing media; BR02 mill residues; CR02 biochar in feed, manure and water.