Nitrous oxide from denitrification: Influence of field management, environmental conditions, and nutrient availability

Foltz, Mary E

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https://hdl.handle.net/2142/113309 Copy

Description

Title

Nitrous oxide from denitrification: Influence of field management, environmental conditions, and nutrient availability

Author(s)

Foltz, Mary E

Issue Date

2021-07-13

Director of Research (if dissertation) or Advisor (if thesis)

Zilles, Julie

Doctoral Committee Chair(s)

Guest, Jeremy

Committee Member(s)

• Bollero, German
• Koloutsou-Vakakis, Sotiria

Department of Study

Civil & Environmental Eng

Discipline

Environ Engr in Civil Engr

Degree Granting Institution

University of Illinois at Urbana-Champaign

Degree Name

Ph.D.

Degree Level

Dissertation

Keyword(s)

• nitrous oxide
• denitrification
• agriculture

Abstract

At the global scale, agriculture contributes significantly to emissions of nitrous oxide (N2O), a potent greenhouse gas and important ozone-depleting substance. To alleviate this environmental issue, there is a need to explore managements and conditions that minimize N2O emissions from agricultural systems. My work combined field, lab, and modeling techniques to decrease agricultural N2O emissions. First, I aimed to understand how field management and environmental conditions influenced N2O emissions and how well predictive models captured these relationships. To this end, I used field measured N2O emissions from agricultural fields under different nutrient management practices and climate conditions to evaluate models and make recommendations for model improvement. Model errors surrounded precipitation events and spring thaw prior to fertilization, highlighting the importance of understanding the relationship between precipitation and thaw events on N2O from denitrification. Due to a lack of field measurements prior to fertilization, I conducted a year-round field N2O measurement campaign and incorporated laboratory denitrification potential measurements, quantification of nitrogen cycling gene abundances, and predictive modeling to fully understand factors influencing differences in measured N2O emissions. The study identified spring thaw N2O emissions in the U.S. Midwest and a connection between denitrification functional genes and potentials. Since denitrification was the major contributor of N2O emissions in my work, I then specifically targeted N2O emissions from denitrification to assess factors driving the N2O ratio, a measure of denitrification’s potential for completion. Using a meta-analysis on the N2O ratio calculated using laboratory denitrification measurements of globally diverse soils, I identified three major driving factors for denitrification completion: experimental nutrient additions, soil pH, and soil texture. Overall, through a better understanding of how field management practices, environmental conditions, and nutrient availability influence N2O emissions from denitrification, my work addresses agricultural N2O and highlights ways to decrease global emissions.

Graduation Semester

2021-08

Type of Resource

Thesis

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http://hdl.handle.net/2142/113309

Copyright and License Information

Copyright 2021 Mary Foltz

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