Hydrological controls on greenhouse gas fluxes and soil carbon quality in a Belgian floodplain

Summary

This study demonstrates that floodplain hydrology is a critical regulator of greenhouse gas emissions and soil carbon dynamics, with water table position and moisture regime fundamentally altering microbial temperature sensitivity and methane production. Across three hydrological zones in the Belgian loess belt, the authors found that maintaining shallow but aerobic water tables through rewetting reduced CO₂ emissions and their temperature sensitivity, whilst limiting CH₄ contributions to total GHG flux. The findings support floodplain rewetting as a targeted climate regulation strategy that exploits hydrological constraints on microbial activity.

UK applicability

UK floodplains, particularly in lowland regions, face similar historical drainage and land-use modification pressures. These findings are directly applicable to UK floodplain restoration and wetland creation schemes, especially where climate mitigation through reduced soil respiration is an objective; however, soil type (loess-derived) and climate differ from many UK contexts, so field validation across UK soil and hydrological conditions would strengthen the case for adoption in UK environmental policy.

Key measures

Soil CO₂ and CH₄ flux measurements; temperature sensitivity (Q10); C-specific basal respiration (R10, µg CO₂-C gC⁻¹ h⁻¹); soil organic carbon, nitrogen, C/N ratio; thermal properties via differential scanning calorimetry (Energy Density and T50)

Outcomes reported

The study measured soil CO₂ and CH₄ fluxes across three hydrological zones during the wettest year on record, and characterised soil carbon quality in relation to microbial respiration. It assessed how water table depth, moisture conditions, and land use (forest, grassland, cropland, marsh) influence temperature sensitivity of respiration and methane emissions.

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