Impact of freeze-thaw cycles on greenhouse gas emissions in marginally productive agricultural land under different perennial bioenergy crops

Augustine K Osei; Fereidoun Rezanezhad; Maren Oelbermann

doi:10.1016/j.jenvman.2024.120739

Impact of freeze-thaw cycles on greenhouse gas emissions in marginally productive agricultural land under different perennial bioenergy crops

J Environ Manage. 2024 Apr:357:120739. doi: 10.1016/j.jenvman.2024.120739. Epub 2024 Mar 28.

Authors

Augustine K Osei¹, Fereidoun Rezanezhad², Maren Oelbermann³

Affiliations

¹ School of Environment, Resources and Sustainability. University of Waterloo, 200 University Avenue W, Waterloo, ON, N2L 3G1, Canada. Electronic address: a2osei@uwaterloo.ca.
² Ecohydrology Research Group, Department of Earth and Environmental Sciences and Water Institute, University of Waterloo, 200 University Avenue W, Waterloo, ON, N2L 3G1, Canada.
³ School of Environment, Resources and Sustainability. University of Waterloo, 200 University Avenue W, Waterloo, ON, N2L 3G1, Canada.

PMID: 38552522
DOI: 10.1016/j.jenvman.2024.120739

Abstract

Knowledge of freeze-thaw-induced carbon (C) and nitrogen (N) cycling and concomitant nitrous oxide (N₂O) and carbon dioxide (CO₂) emissions in perennial bioenergy crops is crucial to understanding the contribution of these crops in mitigating climate change through reduced greenhouse gas (GHG) emissions. In this study, a 49-day laboratory incubation experiment was conducted to compare the impact of freeze-thaw cycles on N₂O and CO₂ emissions in different perennial bioenergy crops [miscanthus (Miscanthus giganteus L.), switchgrass (Panicum virgatum L.), and willow (Salix miyabeana L.)] to a successional site and to understand the processes controlling the N₂O and CO₂ emissions in these crops. The results showed that freeze-thaw cycles caused a decline in dissolved organic C (DOC) and dissolved inorganic N (DIN) concentrations but enhanced the dissolved organic N (DON) and nitrate (NO₃^-). Although, freeze-thaw decreased water stable soil aggregates in all the bioenergy crops and successional site, this did not have any significant impact on N₂O and CO₂ emissions, suggesting that the N₂O and CO₂ emitted during the freeze-thaw cycles may have originated mostly from cellular materials released from lysis and death of microbial biomass rather than from soil aggregate disruption. Cumulative N₂O emissions measured over the 49-day incubation period ranged from 148 mg N₂O-N m^-2 to 17 mg N₂O-N m^-2 and were highest in miscanthus followed by willow, switchgrass, and successional site. Cumulative CO₂ on the other hand was highest in the successional site than any of the bioenergy crops and ranged from 25,262 mg CO₂-C m^-2 to 15,403 mg CO₂-C m^-2 after the 49 days. Higher N₂O emissions in the miscanthus and willow than switchgrass and successional site were attributed to accelerated N losses as N₂O. Results from our study indicate that managing perennial bioenergy crops on low productive agricultural lands to reduce freeze-thaw related GHG emissions and climate change mitigation is dependent on the crop species grown.

Keywords: Freeze-thaw cycle; Marginal land; N(2)O and CO(2) emissions; Perennial bioenergy crops; Soil C/N ratio; Water stable soil aggregates.

MeSH terms

Agriculture / methods
Carbon Dioxide / analysis
Greenhouse Gases* / analysis
Nitrous Oxide / analysis
Panicum*
Soil

Substances

Greenhouse Gases
Carbon Dioxide
Soil
Nitrous Oxide