Title: Nitrogen Leaching From Agricultural Soils Under Imposed Freeze-Thaw Cycles: A Column Study With and Without Fertilizer Amendment,Impact of Winter Soil Processes on Nutrient Leaching in Cold Region Agroecosystems, 2018
Citation: Krogstad, K., Jensen, G., Gharasoo, M., Hug, L., Van Cappellen, P., Rezanezhad, F. (2022). Impact of Winter Soil Processes on Nutrient Leaching in Cold Region Agroecosystems. Federated Research Data Repository. https://doi.org/10.20383/102.0373
,Krogstad, K., Jensen, G., Gharasoo, M., Hug, L., Van Cappellen, P., Rezanezhad, F. (2022). Impact of Winter Soil Processes on Nutrient Leaching in Cold Region Agroecosystems. Federated Research Data Repository. https://doi.org/10.20383/102.0373
Study Site: rare Charitable Research Reserve, Cambridge, Ontario, Canada,Rare Charitable Research Reserve
Purpose: This projects aims to examine the impact of freeze-thaw cycling on fertilizer leaching and nitrification inhibitor efficacy. Results suggest that nitrogen fertilizer is susceptible to nitrification following freeze-thaw cycling in agricultural soil and nitrification inhibitor effectiveness may be detrimentally affected by freeze-thaw cycling. Samples for both experiments were collected at the rare Charitable Reserve and project data was collected at the University of Waterloo Ecohydrology Research Group laboratories. Funding for this project was provided by the Canada First Research Excellence Fund under the Global Water Futures Program.
For the dissolved organic carbon/total nitrogen and dissolved inorganic carbon data for both the soil column and sacrificial batch experiment, measurements were taken using a Shimadzu TOC-LCPH/CPN analyzer. For the ion chromatography data for both experiments, measurements were taken using a Dionex ICS-5000. pH and EC measurements were taken using LAQUA Horiba B-213 Twin meters. For the inductively coupled plasma measurements for both experiments, measurements were taken using a Thermo Scientific iCAP 6300.,The data in this study was collected to investigate the impacts of changing non-growing season climates, particularly freeze-thaw cycles (FTCs), on soil processes, nutrient losses, and agricultural sustainability in cold regions. Specifically, the study aimed to understand the effects of FTCs on soil properties, assess nutrient loss from agricultural soils, evaluate fertilizer practices, explore nitrification inhibitor efficacy, improve soil and nutrient management strategies. The ultimate goal was to inform sustainable agricultural practices by deepening the understanding of nutrient dynamics during winter, contributing to the improvement of water quality and soil health in cold region agroecosystems.
Abstract: Cold regions are warming faster than the rest of the planet, with the greatest warming occurring during the winter and shoulder seasons. Warmer winters are further predicted to result in more frequent soil freezing and thawing events. Freeze-thaw cycles affect biogeochemical soil processes and alter carbon and nutrient export from soils, hence impacting receiving ground and surface waters. Cold region agricultural management should therefore consider the possible effects on water quality of changing soil freeze-thaw dynamics under future climate conditions. In this study, soil column experiments were conducted to assess the leaching of fertilizer nitrogen (N) from an agricultural soil during the non-growing season. Identical time series temperature and precipitation were imposed to four parallel soil columns, two of which had received fertilizer amendments, the two others not. A 15-30-15 N-P-K fertilizer (5.8% ammonium and 9.2% urea) was used for fertilizer amendments. Leachates from the soil columns were collected and analyzed for major cations and anions. The results show that thawing following freezing caused significant export of chloride (Cl−), sulfate (SO42−) and nitrate (NO3−) from the fertilizer-amended soils. Simple plug flow reactor model calculations indicated that the high NO3− concentrations produced during the fertilized soil thawing events were due to nitrification of fertilizer N in the upper oxidized portion of the soil. The very low concentrations of NO3− and ammonium in the non-fertilized soils leachates implied that the freeze-thaw cycles had little impact on the mineralization of soil organic N. The findings, while preliminary, indicate that unwanted N enrichment of aquifers and rivers in agricultural areas caused by fall application of N fertilizers may be exacerbated by changing freeze-thaw activity.,High-latitude cold regions are warming more than twice as fast as the rest of the planet, with the greatest warming occurring during the winter. Warmer winters are associated with shorter periods of snow cover, resulting in more frequent and extensive soil freezing and thawing. Freeze-thaw cycles (FTC) influence soil chemical, biological, and physical properties and any changes to winter soil processes may impact carbon and nutrients export from affected soils, possibly altering soil health and nearby water quality. Changes to non-growing season climate affect soil biogeochemical processes and fluxes and understanding these changes is critical for predicting nutrient availability in cold region ecosystems and their impacts on downstream water quality.
These impacts are relevant for agricultural soils and practices in cold regions as they are important in governing water flows and quality within agroecosystems. Agricultural systems are source areas for nutrient pollutants due to fertilizer use and have been the target of numerous management strategies. Sustainable agricultural practices have been increasingly employed to mitigate nutrient loss due to erosion, but nutrient export via surface runoff, subsurface leaching, and volatilization allows for continued high nutrient losses (Beach et al., 2018; King et al., 2017).
Chapter 1 of thesis discusses the non-growing season climate changes altering winter soil processes and reviews the major nitrogen transformation processes leading to nitrogen losses in agricultural soils. In Chapter 2, I present a soil column experiment to assess the leaching of nutrients from fertilized agricultural soil during the non-growing season. Four soil columns were exposed to a non-growing season temperature and precipitation model and fertilizer amendments were made to two of the columns to determine the efficacy of fall-applied fertilizers and compared to other two unfertilized control columns. Leachates from the soil columns were collected and analyzed for cations and anions. The experiment results showed that a transition from a freeze period to a thaw period resulted in significant loss of chloride (Cl-), sulfate (SO42-) and nitrate (NO3-). Even with low NO3- concentrations in the applied artificial rainwater and fertilizer, high NO3- concentrations (~150 mg L-1) were observed in fertilized column leachates. Simple plug flow reactor model results indicate the high NO3- leachates are found to be due to active nitrification occu
Summary: Item exited embargo and became publicly available on 2022-09-30,This collection includes a subset of theses submitted by graduates of the University of Waterloo as a partial requirement of a degree program at the Master's or PhD level.
Item exited embargo and became publicly available on 2022-09-30
Research: Canada First Research Excellence Fund (CFREF)
Global Water Futures Program (GWF),Canada First Research Excellence Fund (CFREF)
Global Water Futures Program (GWF)
Global Water Futures (GWF)
Further Info: Krogstad, K., Jensen, G., Gharasoo, M., Hug, L., Van Cappellen, P., Rezanezhad, F. (2022). Impact of Winter Soil Processes on Nutrient Leaching in Cold Region Agroecosystems.Front. Environ. Sci. 10. https://doi.org/10.3389/fenvs.2022.915329,none
Status: Complete
Keywords:
soil carbon,
Winter soil processes,
Nutrient leaching,
Fertilizer management,
Geographical coordinates: North: 44.0000, South: 42.5000 East: -80.0000 West: -81.0000
Bounding Temporal Extent: Start Date: 2018-10-15, End
Date: 2019-10-01
