World Soil Day is observed globally on December 5 to raise awareness of the importance of soil health, given the crucial role of soil in maintaining healthy ecosystems and supporting human life. As part of an ongoing commitment to sustainability and environmental health, the University of Guelph was joined by the Ontario Ministry of Agriculture, Food, and Agribusiness (OMAFA), Soils At Guelph researchers, the Greenbelt Foundation, graduate students, and many more for a day of celebrating World Soil Day 2025.
Here’s a look at the innovative research done by the winners of the Student Research Showcase.
Poster Presentation Winners:
- Amanda Mitchell, How Does Long-Term Cover Cropping Impact Arbuscular Mycorrhizal and General Fungal Colonization in Nitrogen Limited Winter Wheat?
- Emma Wegener, Variation in Northern Peat Depths Across Ecosystem Types
- Nastaran Chalabianlou, Resolving Organic–Inorganic Carbon Overlap: Comparing Soil Organic Carbon (SOC) Measurement Methods to Improve Accuracy in Calcareous Soils
Oral Presentation Winners:
- Megan Schuetz, Digging into Soil Biodiversity: Can Bacteriophages Provide Insights into Soil Health
- Navdeep Saini, Manure Acidification Suppresses Methanogenic Activity and Reduces Methane Emissions
- Evan Mayer, Dis-cover-ing Soils of the Future: Long-Term Cover Cropping Can Promote Plant-Beneficial Microbes
Megan Schuetz
Megan Schuetz, a Master’s student in Environmental Sciences, aims to explore the most abundant viruses in agricultural soils, called bacteriophages.
Soil microorganisms drive key ecosystem services, such as nutrient cycling; however, viruses remain underexplored components of agricultural soils.
Viruses can have a negative connotation of something that can make you sick, such as the common cold or COVID-19. However, bacteriophages, viruses that specifically infect bacteria, are harmless to humans.
Bacteriophages use bacteria as their host and force them to produce new viruses. These new viruses then burst the host cell, killing it and releasing nutrients back into the environment. In oceans, bacteriophages play a key role in nutrient cycling and population control; yet they remain understudied in more physically complex environments, such as soil.
Under the supervision of Dr. Kari Dunfield (University of Guelph) and Dr. Hany Anany (Agriculture and Agri-Food Canada), this research aims to uncover bacteriophage diversity and their potential role in the soil ecosystem under different long-term agricultural management practices. Enhancing our understanding of all components of the soil ecosystem, including viruses, will provide greater insights for protecting soil health.
If you would like more information about Megan Schuetz’s research, please contact Dr. Kari Dunfield at dunfield@uoguelph.ca.
Amanda Mitchell
Amanda Mitchell, a PhD student in Environmental Sciences, investigates how long-term cover cropping impacts arbuscular mycorrhizal and general fungal colonization in nitrogen-limited winter wheat.
Winter wheat is widely grown across Ontario and is less efficient at using nitrogen fertilizer than corn crops. Plants recruit beneficial microorganisms, such as arbuscular mycorrhizal fungi (AMF), to manage nutrient and water limitations. Associations with AMF have been shown to improve nitrogen use efficiency (NUE) in winter wheat. For a plant to recruit this beneficial microbial community, the necessary microorganisms must be present in the soil. Long-term cover cropping has been shown to increase microbial abundance and diversity in soils, suggesting that crops grown in long-term cover cropping soils may be more resilient to stressful conditions. The objective of this study was to identify whether long-term cover cropping would increase beneficial plant-microbe relationships and decrease detrimental relationships under N stress.
A long-term cover cropping trial was established in 2008 in Ridgetown, Ontario, where plots with no cover crop control or fall cover crops of radish, rye, oat, or radish and rye were established. Winter wheat was established in these plots in November 2024 and split into sub-plots, where either 0 lbs N/ acre or 100 lbs N/ acre was applied in April 2025. Winter wheat plants were sampled at grain filling, and roots were examined under the microscope for AMF and general fungal colonization. We found no impact of N treatment on AMF colonization; however, cover cropping with non-mycorrhizal crops (radish) did decrease AMF colonization compared to cover cropping with Rye. There was no impact of cover cropping or N treatment on fungal colonization by non-AMF species; the 0 N treatment had ~30 bu/ac lower yield, primarily driven by the radish-rye cover cropping treatment, suggesting plants in 0 lbs N / acre treatments did have some level of N stress, particularly with a history of radish-rye cover cropping. These results suggest that a decrease in AMF colonization due to cover cropping with non-mycorrhizal crops did not impact winter wheat’s ability to thrive under low N conditions.
If you would like more information about Amanda Mitchell’s research, please contact Dr. Kari Dunfield at dunfield@uoguelph.ca.
Navdeep Saini
Navdeep Saini, a PhD student in Environmental Sciences, is investigating whether a low-dose sulphuric acid additive can reduce methane emissions from stored liquid swine manure by altering the microbial communities responsible for methane production. As liquid swine manure is an important soil amendment in crop production, reducing methane emissions from its storage is a key step in decreasing the overall environmental footprint of this practice.
Under the supervision of Dr. Kari Dunfield (University of Guelph) and Dr. Andrew VanderZaag (Agriculture and Agri-Food Canada), anaerobic manure incubation experiments were conducted at Agriculture and Agri-Food Canada, while microbial analyses were carried out at the University of Guelph. Liquid swine manure was stored for 183 days at 17°C, 20°C, 23°C, and 37°C, with increasing rates of sulphuric acid. Results showed that methane emissions were strongly temperature-dependent and delayed by acidification across all storage temperatures.
To better understand the microbial mechanisms driving this response, Navdeep extracted DNA and RNA from manure samples to examine active methanogens through mcrA gene expression and to assess microbial community shifts using high-throughput sequencing.
Navdeep’s early findings suggest that acidification suppresses methanogenic activity under cooler storage conditions and delays the recovery of methane-producing communities. Sequencing revealed shifts in active archaeal taxa, including Methanoculleus and Methanosarcina, while dsrB gene expression suggested continued sulphate-reducing bacterial activity under acidified conditions. These findings highlight acidification as a promising microbial-based strategy for reducing methane emissions from Canadian swine manure storage.
If you would like more information about Navdeep Saini‘s research, please contact Dr. Kari Dunfield at dunfield@uoguelph.ca.
Emma Wegener
Emma Wegener, a PhD candidate in Environmental Sciences, is working to reassess the carbon reserves of the Hudson Bay Lowlands under the supervision of Dr. Catherine Dieleman.
The Hudson Bay Lowlands are comprised of mostly peatlands — one of the greatest terrestrial stocks of organic carbon, with current carbon estimates based on roughly 50 individual peat depth measurements, for a landscape nearly the size of Germany, making most of the depths more or less an assumption. This research aims to identify an aboveground variable, like vegetation or ecosystem classification, associated directly with peat depth, which can be used to estimate and subsequently map more accurate stocks of organic carbon stored within these peatland ecosystems.
If you would like more information about Emma Wegener’s research, please contact Dr. Catherine Dieleman at cdielema@uoguelph.ca.
Evan Mayer
Evan Mayer, a PhD student in Environmental Sciences, is looking at how sustainable agricultural management practices influence plant growth-promoting microbes, which are critical for plant growth and fertility in agroecosystems under the supervision of Dr. Kari Dunfield.
To do this, Evan samples soils from long-term agricultural field trials containing different tillage, crop rotation, fertilization, and cover cropping treatments.
These soils are transported to the lab, where Evan extracts DNA, sequences microbial communities, and identifies shifts in microbial communities between management treatments. Evan also uses this DNA to quantify microbial functional genes facilitating plant-beneficial functions, especially cycling of nutrients into plant-available forms, and identify if shifts towards more sustainable practices can enhance these groups.
To date, Evan’s results have shown that diversifying corn-based crop rotations with wheat and fall cover cropping with radish can strongly promote plant-beneficial microbes and enhance nutrient cycling functions. These findings further highlight rotation diversification and cover cropping as practices which facilitate agroecosystem sustainability. Ultimately, these findings could further encourage the use of these sustainable practices through informing farmers and policymakers.
If you would like more information about Evan Mayer’s research, please contact Dr. Kari Dunfield at dunfield@uoguelph.ca.
Nastaran Chalabianlou
Nastaran Chalabianlou, a postdoctoral researcher in the School of Environmental Sciences at the University of Guelph, is addressing a key challenge in soil science and environmental management: accurately measuring how much carbon is stored in soils. Soil organic carbon (SOC) is essential for soil health and sustainable land management, but in many agricultural soils, naturally occurring inorganic carbon (carbonates) can interfere with measurements and lead to misleading results.
Working with Dr. Adam Gillespie, Chalabianlou is comparing commonly used laboratory methods to determine how reliably they measure organic carbon, especially in deeper soil layers where carbonates are more abundant. To strengthen this work, she has also developed an independent method—calcimetry—to directly measure inorganic carbon, allowing for more accurate separation of organic and inorganic carbon pools.
Using meter-deep soil samples from southern Ontario, her research shows that while most methods perform well in surface soils, their accuracy declines in carbonate-rich subsoils. By identifying these limitations and improving measurement approaches, this work supports more reliable carbon accounting and better-informed decisions for soil and land management.
For more information about Nastaran Chalabianlou’s research, please contact Dr. Adam Gillespie at agilles@uoguelph.ca.
