Nitrous oxide release from agricultural soils under different management practices during freeze-thaw cycles

Author

Julia M. Pupko, University of VermontFollow

Date of Completion

2019

Document Type

Honors College Thesis

Department

Environmental Sciences

Thesis Type

Honors College, Environmental Studies Electronic Thesis

First Advisor

Dr. Carol Adair

Second Advisor

Dr. Aimee Classen

Third Advisor

Dr. Eric Roy

Keywords

nitrous oxide, agriculture, greenhouse gas, freeze-thaw cycle, management

Abstract

Nitrous oxide (N₂O) is a greenhouse gas 298 times more powerful than carbon dioxide (CO₂), and is a source of ozone-depleting nitrogen oxides. Agricultural soils are estimated to account for over 75% of anthropogenic N₂O emissions and 23-31% of total global N₂O emissions (Charles et al., 2017). Soil release of N₂O is primarily from the biological processes of nitrification and denitrification, with large emission fluxes surrounding freeze-thaw cycles (FTCs). While increasing numbers of studies on agricultural- and FTC-induced N₂O emissions have been done over recent decades, there is still little understanding of potential interactions between agricultural management practices and FTCs. The purpose of this study is to identify the source of N₂O emissions during FTCs – nitrification or denitrification – and the drivers of these emissions from conventional versus Best Management Practice (BMP) agricultural fields. An incubation study was conducted using soil samples from each field. The samples were subject to a frozen or thaw treatment, during which N₂O emissions and potential drivers of nitrification and denitrification (e.g., nitrate, nitrite, ammonium, and microbial biomass and activity) were measured. Understanding the source and driving factors of N₂O emissions from agricultural fields is important, as it will shape management practices of these lands to reduce greenhouse gas emissions and mitigate climate change.

Comments

Some images have been omitted in this online version. The full version is available only in the Honors College office.

Creative Commons License

This work is licensed under a Creative Commons Attribution-Noncommercial-No Derivative Works 3.0 License.

Recommended Citation

Pupko, Julia M., "Nitrous oxide release from agricultural soils under different management practices during freeze-thaw cycles" (2019). UVM Honors College Senior Theses. 292.
https://scholarworks.uvm.edu/hcoltheses/292