Freeze-thaw cycle, soil moisture, and thawing temperature effects on nitrogen dynamics in a Black Chernozemic sandy loam
| dc.contributor.author | Kpankpari, Roger | |
| dc.contributor.examiningcommittee | Zvomuya, Francis (Soil Science) | |
| dc.contributor.examiningcommittee | Carvalho, Henrique (Soil Science) | |
| dc.contributor.supervisor | Mante, Afua | |
| dc.date.accessioned | 2025-03-26T16:11:38Z | |
| dc.date.available | 2025-03-26T16:11:38Z | |
| dc.date.issued | 2025-03-26 | |
| dc.date.submitted | 2025-03-26T15:42:05Z | en_US |
| dc.degree.discipline | Soil Science | |
| dc.degree.level | Master of Science (M.Sc.) | |
| dc.description.abstract | Many farmers in the Canadian Prairies apply urea during the fall before freezing with the aim to reduce field operational tasks in the spring considering the short growing season and the risk of excess soil moisture delaying field operation and also leverage the lower fertilizer prices in the fall. Farmers are advised to apply fertilizers at a temperature of 5°C or lower to reduce nitrogen (N) losses. This recommendation, however, does not take into account the interaction between temperature and moisture and how that impacts N- dynamics in the soil and the potential impact on N2O. The objective of this study was to evaluate the effects of soil freezing and thawing cycle, moisture content (32%, 50%, or 100% water-filled pore space, WFPS) and thawing temperature (4, 8, 12, or 16°C) on N2O emissions from a sandy loam soil, treated with stabilized urea-based fertilizer (SuperU). The results showed that moisture significantly affected N2O emissions under all temperatures, with the highest emissions recorded for 100% WFPS at 16°C. SuperU was not effective in reducing cumulative N2O emissions at 100% WFPS. There was a significant positive correlation between volumetric heat capacity and N2O flux at higher thawing temperatures. The results demonstrate the potential of N2O reduction when urea is applied in bands of 5 cm deep at a temperature of 5°C or lower with soil moisture at or below 50% WFPS. However, spring conditions present a high risk of N losses. | |
| dc.description.note | May 2025 | |
| dc.identifier.uri | http://hdl.handle.net/1993/38951 | |
| dc.language.iso | eng | |
| dc.subject | nitrous oxide | |
| dc.subject | freeze-thaw cycle | |
| dc.subject | SuperU | |
| dc.subject | urea | |
| dc.subject | water-filled pore space | |
| dc.subject | temperature | |
| dc.subject | nitrate | |
| dc.subject | ammonium | |
| dc.subject | volumetric heat capacity | |
| dc.title | Freeze-thaw cycle, soil moisture, and thawing temperature effects on nitrogen dynamics in a Black Chernozemic sandy loam | |
| local.subject.manitoba | yes | |
| project.funder.name | NSERC Discovery Grant and University of Manitoba Startup Grant |