TY - JOUR
T1 - Mechanism of Water Retention and Gas Flux in Unsaturated Soils Amended With Four Different Pyrolyzed Plant Based Biomass
AU - Qinyue, Yao
AU - Kumar, Rakesh
AU - Liu, Wenliang
AU - Garg, Ankit
AU - Jiang, Mingjie
N1 - Publisher Copyright:
© 2025 British Society of Soil Science.
PY - 2025/4/1
Y1 - 2025/4/1
N2 - Biochar, as an environment-friendly soil amendment, has been extensively proposed in landfill cover, primarily for promoting soil hydraulic properties, such as hydraulic conductivity and soil water retention. However, the impact of biochar derived from various feedstocks on soil-biochar mix properties, particularly gas permeability under unsaturated conditions, remains under-explored. This study evaluates how different types of biochar influence gas permeability and soil water retention. Five biochars pyrolyzed using different biomass waste, such as apple wood, reed straw, walnut, corn cob and corn straw, were each mixed with sandy soil in a 5% mass ratio. Gas permeability and hydrological response (water content, matric suction) were measured during wet-dry cycles. Results indicated that biochar amendments generally enhanced water retention compared to bare soil. Apple wood biochar, in particular, significantly improved both water content (reaching 90% of the control's maximum moisture content) and suction (peaking at 2755 kPa), outperforming reed straw, walnut, corn cob and corn straw biochars. This enhancement stems from apple wood biochar's hydrophilic functional groups (e.g., –OH), which improve soil hydrophilicity and water-biochar interactions. Its large specific surface area and tightly arranged micropores further enhance suction. Gas permeability rose with increasing suction, with reed straw and apple wood biochars increasing gas permeability by 196% due to their larger average pore sizes and the formation of more meso-macro pore structures in the sandy soil. Conversely, walnut and corn cob biochars reduced soil permeability, suggesting their suitability for high-pressure applications. These findings guide the use of biochar-amended soil in landfill covers to mitigate gas emissions.
AB - Biochar, as an environment-friendly soil amendment, has been extensively proposed in landfill cover, primarily for promoting soil hydraulic properties, such as hydraulic conductivity and soil water retention. However, the impact of biochar derived from various feedstocks on soil-biochar mix properties, particularly gas permeability under unsaturated conditions, remains under-explored. This study evaluates how different types of biochar influence gas permeability and soil water retention. Five biochars pyrolyzed using different biomass waste, such as apple wood, reed straw, walnut, corn cob and corn straw, were each mixed with sandy soil in a 5% mass ratio. Gas permeability and hydrological response (water content, matric suction) were measured during wet-dry cycles. Results indicated that biochar amendments generally enhanced water retention compared to bare soil. Apple wood biochar, in particular, significantly improved both water content (reaching 90% of the control's maximum moisture content) and suction (peaking at 2755 kPa), outperforming reed straw, walnut, corn cob and corn straw biochars. This enhancement stems from apple wood biochar's hydrophilic functional groups (e.g., –OH), which improve soil hydrophilicity and water-biochar interactions. Its large specific surface area and tightly arranged micropores further enhance suction. Gas permeability rose with increasing suction, with reed straw and apple wood biochars increasing gas permeability by 196% due to their larger average pore sizes and the formation of more meso-macro pore structures in the sandy soil. Conversely, walnut and corn cob biochars reduced soil permeability, suggesting their suitability for high-pressure applications. These findings guide the use of biochar-amended soil in landfill covers to mitigate gas emissions.
KW - biochar
KW - gas permeability
KW - landfill cover
KW - soil water retention
KW - suction
UR - http://www.scopus.com/inward/record.url?scp=105004221569&partnerID=8YFLogxK
U2 - 10.1111/sum.70069
DO - 10.1111/sum.70069
M3 - Article
AN - SCOPUS:105004221569
SN - 0266-0032
VL - 41
JO - Soil Use and Management
JF - Soil Use and Management
IS - 2
M1 - e70069
ER -