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ARS Home » Northeast Area » Beltsville, Maryland (BARC) » Beltsville Agricultural Research Center » Sustainable Agricultural Systems Laboratory » Research » Publications at this Location » Publication #425119
Research Project: Soil, Crop, and Manure Biochemistry and Molecular Ecology: Bridging Knowledge Gaps in Microbiome Response to Management

Location: Sustainable Agricultural Systems Laboratory

Title: Freeze-thaw events and nitric oxide, nitrous oxide, and carbon dioxide fluxes in a U.S. corn belt soil

Author
item GROFFMAN, PETER - City University Of New York
item MARTEL, LISA - Cary Institute Of Ecosystem Studies
item HICKMAN, JONATHAN - Columbia University - New York
item MILES, MADELINE - University Of Virginia
item Maul, Jude
item SUYKER, ANDY - University Of Nebraska
item AWADA, TALA - University Of Nebraska

Submitted to: Journal of Geophysical Research-Biogeosciences
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/10/2026
Publication Date: 2/21/2026
Citation: Groffman, P.M., Martel, L.D., Hickman, J.E., Miles, M., Maul, J.E., Suyker, A., Awada, T. 2026. Freeze-thaw events and nitric oxide, nitrous oxide, and carbon dioxide fluxes in a U.S. corn belt soil. Journal of Geophysical Research-Biogeosciences. 131(2). Article e2025JG009254. https://doi.org/10.1029/2025JG009254.
DOI: https://doi.org/10.1029/2025JG009254

Interpretive Summary: Carbon is the key component of soil organic matter, which is crucial to supplying the nutrients and water needed to support cash crop yield. Soil organisms such as bacteria, fungi, and animals break down crop residues using leftover fertilizer, in the process releasing carbon into the atmosphere in the form of gases such as carbon dioxide and methane. The amount of carbon lost in gaseous form to the atmosphere (“flux”) is sensitive to changes in winter soil conditions (e.g., soil freezing and thawing events, soil moisture, depth of snow, and the type and amount of soil organisms present in the soil); there is great uncertainty about how variation in the nature and intensity of these factors affect fluxes. We conducted laboratory experiments to assess the effects of varied intensity and frequency of freezing on carbon dioxide and methane fluxes from soils cropped to corn in Nebraska, USA. We also measured soil carbon and nitrogen cycling and collected data on the living components of the soil such as microbial biomass and soil enzyme activity. We found that the intensity and duration of the gas fluxes depends on how complex changes in soil factors such as temperature and moisture (snow, frost, temperature, moisture) interact to affect winter soil conditions. This work provides information that can be used by researchers to better model carbon flows in agricultural systems, which will ultimately be useful to crop advisors and other technical service providers assisting farmers in maintaining and increasing soil carbon levels to support cash crop yield.

Technical Abstract: Fluxes of carbon dioxide (CO2), nitrous oxide (N2O) and nitric oxide (NO) from agricultural soils to the atmosphere drive climate warming and affect atmospheric chemistry. We conducted laboratory experiments to assess the effects of varied intensity and frequency of freezing on these fluxes from soils cropped with maize in Nebraska, U.S. We evaluated the effects of variations in freezing temperature, freezing degree days (FDDs: the sum of the number of degrees below zero Celsius for each respective day below zero, for example, 12 days at -2°C is equal to 24 FDDs), and freeze-thaw cycling. Soil cores were incubated in gas-tight chambers, and fluxes of N2O and CO2 were directly measured by gas chromatography, while NO fluxes were measured with a chemiluminescence detector. We made concurrent measurements of potential net N mineralization, net nitrification, microbial biomass, and denitrification enzyme activity. NO was the most responsive to freezing treatments, with some treatments markedly stimulating emission (75FDD, 15FDD) and one treatment (15FDD Fast) significantly reducing emission compared to the control. Effects on N2O and CO2 were less marked than effects on NO, but there was significant stimulation of both these fluxes in the most extreme freezing treatment (75FDD) and significant reductions in flux in the 15FDD Fast treatment at several sampling dates. Our results suggest that severe freezing events influence the flux of important trace gases. These events, and how changes in winter climate affect them, may need to be integrated into climate models given their implications for atmospheric chemistry.