As World Soil Day approaches on December 5th, the spotlight shines on the critical role soil health plays in sustaining life on Earth. Soil is the cornerstone of food production, climate regulation, and ecosystem resilience. At the University of Guelph’s Ontario Agricultural College (OAC), graduate students are leading innovative research to improve soil health, shaping the future of agriculture and sustainability.

From reducing soil compaction to addressing microplastic contamination, their work underscores the value of healthy soils for ensuring food security and mitigating climate change. Here’s a look at the groundbreaking research being done by four exceptional students and its far-reaching impact.

Tackling Soil Contamination: Stephen Sumary

Stephen Sumary, a Master’s student in Environmental Sciences [1] is investigating a growing concern in agricultural soils—microplastic contamination. Sumary examines how municipal compost waste introduces microplastics into soils and explores their vertical distribution in the topsoil.

“Compared to aquatic environments, the study of microplastics in terrestrial systems is significantly underrepresented in the scientific community,” explains Sumary. “Once in the soil, microplastics become a very harmful contaminant. They disrupt soil structure, impact nutrient cycling, and disturb microbial communities. These factors are all critical to crop development and growth and, as a result, can harm crop yields.”

Sumary’s research aims to empower farmers by helping them understand the impact of microplastics on soil health and make informed decisions about compost use. His findings also provide a foundation for scientists to conduct more targeted studies on how microplastics accumulate and migrate through soils.

“Soil health is vital for our agri-food systems,” Sumary emphasizes. “Healthy soils support crops with minimal reliance on external inputs such as irrigation and fertilizers, reducing environmental harm. Without healthy soils, we would face challenges in meeting crop yield demands and maintaining food quality, jeopardizing food security.”

Fighting Soil Compaction: Olatunbosun Ayetan

Olatunbosun Ayetan, a PhD student in Environmental Sciences [2] from Nigeria, is leveraging cutting-edge technology to tackle soil compaction—a major threat to soil health. Under the supervision of Dr. Richard Heck [3], Ayetan uses X-ray Computed Tomography to study how tractor tire pressure and soil management practices influence soil structure.

“Soil is the backbone of our agri-food system,” says Ayetan. “It provides the foundation for crop growth, supports water and nutrient cycles, and plays a key role in regulating the environment.”

Ayetan’s research confirms that reducing tire pressure can significantly minimize compaction, while practices like strip tillage and cover cropping help maintain soil structural quality. His findings offer actionable guidance for farmers, agricultural advisors, and policymakers, promoting sustainable farming practices that preserve soil integrity.

“Maintaining soil quality is essential for sustaining crop production and mitigating environmental degradation for current and future generations,” Ayetan emphasizes.

Enhancing Soil Organic Carbon: Skye Earley

For Skye Earley, a MSc in Environmental Science [2] student from Rockwood, Ontario, soil organic carbon is a cornerstone of her research. Working under the guidance of Drs. Claudia Wagner-Riddle [4] and Adam Gillespie [5], Earley studies ways to reduce the loss of soil organic carbon and maintain it in cropland soils.

“Soil organic carbon is a critical part of soil organic matter, which is a key indicator of soil health,” says Earley. “Healthy soils are not only more productive for growing crops but are also more resilient to challenges like droughts and floods caused by climate change.”

Her work underscores the dual benefits of healthy soils: ensuring better crop yields and contributing to climate change mitigation. By helping farmers build more sustainable agricultural systems, her research supports food security while protecting the environment.

“Soil health is the foundation of our agri-food system,” she explains. “Healthy soils rich in organic matter and nutrients support higher crop yields and better-quality produce, ensuring a stable and secure food supply. They also retain water more effectively, helping crops survive during droughts and reducing flood risks.”

Optimizing Nitrogen Cycling with Cover Crops: Dr. Yajun Peng

Recent PhD in Environmental Science graduate [2] Dr. Yajun Peng, originally from China, focused her research on how cover cropping impacts soil nitrogen availability and organic matter. Under the supervision of Dr. Laura Van Eerd [6], Peng used a nitrogen-15 (15N) tracer technique to study nitrogen cycling in grain corn systems at the University of Guelph’s Ridgetown Campus [7].

“Our findings demonstrated that using cover crops—even just one time—can increase soil nitrogen availability and organic nitrogen retention, ultimately improving crop yields,” says Peng. “This highlights the importance of soil organic matter in improving nitrogen cycling.”

Peng’s research offers vital insights for farmers, researchers, and policymakers interested in sustainable soil management. Her work underscores how building healthy soil supports global food security while addressing broader environmental challenges.

“Healthy soil is a prerequisite for healthy food and a sustainable agroecosystem,” Peng emphasizes. “Building up healthy soil through sustainable management is critical to meeting global food demands and mitigating climate change.”

Why Soil Health Matters

The work of Ayetan, Sumary, Earley, and Peng illustrates that soil health is more than just an agricultural issue—it’s a societal one. Healthy soils are essential for growing food, supporting ecosystems, and addressing climate challenges. Yet, soils are under increasing pressure from erosion, contamination, salinization, and climate change.

Research at the University of Guelph’s OAC is helping address these challenges, providing practical solutions to improve soil health and ensuring a sustainable agri-food system. On World Soil Day, we celebrate the efforts of these graduate students and the broader scientific community working to secure our soil and food future.