Table 3 Impacts of biochar amendment in soil on the carbon sequestration potential

Corn silage, 500 °C

Lab-scale

Forests and agricultural soils

1% (w/w)

No impact on forest soil, but reduced CO₂ emission from the agricultural soil

⁶⁶

Swine manure, 600–800 °C

Lab-scale

Rice paddy field

2% (w/w)

Significant reduction of CO₂ emission after biochar treatment

⁸⁵

Reed straw, 400 °C (nZVI-biochar)

Lab-scale

Saline-alkali soil

0.15–0.45% (w/w)

Significant reduction of CO₂ emission after nZVI-biochar treatment

⁵⁵

Corn cob, 250 °C

Lab-scale

Acidic sandy soil

∼0.84% (w/w)

Reduction of CO₂ emission by 11.8%

⁸⁶

Rice husk, 700 °C

Lab-scale

Soil from university campus

2% (w/w)

Reduction of CO₂ emission by 80.29%

⁵⁴

Rice husk, 700 °C (H₃PO₄-biochar)

Lab-scale

Soil from university campus

2% (w/w)

Reduction of CO₂ emission by 91.60%

⁵⁴

Rice husk, 700 °C (H₃PO₄–nZVI-biochar)

Lab-scale

Soil from university campus

2% (w/w)

Reduction of CO₂ emission by 88.28%

⁵⁴

Hard wood, 200–600 °C (Steam & CO₂ activation)

Lab-scale

Topsoil (silt loom)

0.75% (w/w)

Reduction of CO₂ emission by 18%

¹⁸³

Wood sawdust, 450 °C

Lab-scale

Surface soil

3.2% (w/w)

Negative priming effects was observed with biochar treatment (−0.22 to –23.56 mg-CO₂–C/g -soil-C)

¹⁸⁴

Peanut shells, 400–500 °C

Lab-scale

Soil from an experimental field

~1.4% (w/w)

Reduced CO₂ emission by 23.61%

¹⁸⁵

Rice straw, 500 °C

Lab-scale

Saline–Alkaline Soil (sandy loam)

~0.77% (w/w)

Reduction of CO₂ emission by 35.19% with addition of biochar as well as straw and urea

¹⁸⁶

Wheat straw, 450 °C

Lab-scale

Irragric Anthrosols

∼1.1% (w/w)

Biochar application decreased CO₂ emission by an average of 23%

⁹¹

Rice husk, 300 °C

Lab-scale

Soil of Bungor Series

∼0.54% (w/w)

Cumulative CO₂ emission reduced by 139.41% compared to control

¹⁵²

Wheat straw, 500–600 °C

Pot experiments

Clay loom soil

50–95% (w/w)

CO₂ emissions reduced by 8.05–31.46%. Higher CO₂ emissions observed at higher biochar dose.

¹⁸⁷

Corn stover, 550 °C

Pot experiments

Garden top soil

3% (w/w)

CO₂ emissions reduced by 15% compared to control soil

¹⁷³

Pine wood, 500–700 °C

Pot experiments

Olton clay loam soil

1% (w/w)

Reduced CO₂ emission by 66.9–72.4%

¹⁸⁸

Corn stalks, 400 °C

Microcosms

Coastal saline soil

16 tons/hectare

Corn stalks-derived biochar showed higher GWMP (−3.84 to −3.17 tonne CO₂-eq/hectare/tonne C) than control treatment (−0.11 tonne CO₂-eq/hectare/tonne C).

⁷⁵

Rice straw

Mesocosm

Rice paddy field

6 tons/hectare

CO₂ uptake increased by 43.5% and decreased the GWP by 375.6 g CO₂-eq/m²/season

⁷⁴

Multiple feedstocks, 280 °C

Pot experiments

Alkaline clay and acidic sandy soil

4 tons/hectare

Biochar with N fertilizer addition reduced CO₂ emission by 7–12%

¹⁸⁹

Corn straw, 360 °C

Microcosm

Agricultural soil

9 tons/hectare

Reduced CO₂ emission by 11%

⁷³

Farm wastes and wood residues, 500–550 °C

Field-scale

Andisol

11 tons/hectare

Biochar amendment reduced CO₂ fluxes. But, no significant differences in CO₂ emission rates among different types of biochar treatments

²⁴

Corn cobs, 500–550 °C

Field-scale

Haplic Acrisols

0–30 tons/hectare

Specific maintenance respiration (qCO₂) reduced by 66–73%

¹¹⁴

Maize straw. 350–550 °C

Field-scale

sandy-loam soil

30 tons/hectare

Reduced CO₂ emission by 33%

¹⁹⁰

Corn straw, 450 °C

Field-scale

Sandy loam soil

20 tons/hectare

Biochar addition enhanced SOC levels and reduced CO₂ emissions

⁷⁶