Figure - available from: Biology and Fertility of Soils
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Percent water filled pore space (WFPS) at the time of soil freezing (15% or 30%) and throughout the seven-day incubation following the onset of soil thawing (at 1.5 or 8.0 °C) and with or without the addition of water to simulate snowmelt infiltration (SM⁺ or SM⁻).
Source publication
Climate change-related warming and increased precipitation may alter winter snow cover and thawing events, and therefore, may carry significant consequences for nitrous oxide (N2O) production pathways such as denitrification, and the abundance and expression of denitrifying microorganisms. We used a soil microcosm study to investigate the combined...
Citations
... The nosZ gene, encoding the enzyme responsible for converting N 2 O to N 2 in the final step of denitrification (Sennett et al. 2024;Yan et al. 2024), was also examined. Although biochar increased nosZ abundance under N deposition, there was no significant correlation between nosZ abundance and denitrification rates (Fig. S4e and S12), indicating that biochar's reduction of N 2 O emissions was not due to enhanced completion of the denitrification process. ...
Subtropical forests are significant contributors to N2O emissions with consequences for climate regulation. Biochar application has emerged as a promising strategy to mitigate soil N2O emissions, yet its effects and the underlying mechanisms under nitrogen (N) deposition in subtropical forests remain poorly understood. A comprehensive 3-year field study within a subtropical forest reveals that N deposition led to a significant increase in soil N2O emissions by 14.6–25.1% annually. However, biochar application resulted in a substantial reduction of these emissions, ranging from 8.0–20.8% each year. Notably, the mitigation effect of biochar was particularly pronounced when N deposition was occurring, leading to an even greater reduction in N2O emissions by 14.2–22.0% annually. This mitigation effect is attributed to biochar’s capacity to lower the nitrification and denitrification rates of soil via reducing levels of ammonium N and water-soluble organic N. Additionally, biochar decreased the abundance of critical microbial genes, including AOAamoA, nirK and nirS, and reduced the activity of key enzymes such as nitrate and nitrite reductase. These findings highlight the potential of straw biochar to effectively mitigate soil N2O emissions in subtropical forests experiencing N deposition, offering important insights for supporting ecosystem sustainability under global climate change.
