Evelyn Brooke Hayes

Topic

Biological Soil Health and Farmer Mental Health in British Columbia, Canada

School of Environmental Studies

Date & location

• Tuesday, September 8, 2026

• 9:00 A.M.

• David Turpin Building

• Room B161

Reviewers

Supervisory Committee

• Dr. John Volpe, School of Environmental Studies, University of Victoria (Co-Supervisor)

• Dr. Eric Higgs, School of Environmental Studies, UVic (Co-Supervisor)

• Dr. Charlotte Norris, School of Environmental Studies, UVic (Member)

• Dr. Tamara Krawchenko, School of Public Administration, UVic (Outside Member)

   

External Examiner

• Dr. Martina Sura-de Jong, Protein Transition & Microbiome, University of Applied Sciences, Leeuwarden, The Netherlands 

Chair of Oral Examination

• Dr. Astrid Brousselle, School of Public Administration, UVic

   

   

Abstract

Agricultural soils and the farmers who work with them operate within socioeconomic and environmental contexts where policy frameworks, measurement approaches, and personal factors shape outcomes for both soil and human health. This dissertation examines the relationships between biological soil health and farmers’ mental health in British Columbia, Canada through four interconnected studies. First, litter decomposition was assessed as a field-based measure of biological soil activity in degraded agricultural soils, refining the Tea Bag Index (TBI) protocol and identifying a biological indicator (Br: Rooibos mass remaining) that improves measurement precision. Second, this measure was validated across 57 farms spanning diverse regions and production systems, where it successfully discriminated between management systems and crop types independent of climate or soil data, showing higher decomposition rates in organic and regenerative systems. Third, relationships were assessed between soil health, farmers’ mental health, and contextual factors including rurality, social networks, production systems, pesticide use, ecological values, and demographics. Hypothesized structural associations were broadly null; a small positive association between value for ecological services and stress was the only supported result, while ownership and revenue per hectare recurred as competitive variables across mental health and soil health outcomes. Fourth, a legislative analysis examined the broader administrative context by documenting where soil, land, human, health, and rurality are coded in sectors and municipal, provincial, federal, and Indigenous legislative instruments in British Columbia. This revealed that soil is described mostly in provincial regulations, while land and human health tend to be described in statutes, which are slower to change. Risk-based language predominates, particularly for human health, although the Organic Matter Recycling Regulation provides soil-forward examples for interdisciplinary policy development. Together, these findings establish biological litter decomposition as an accessible soil health measure; demonstrate its sensitivity to management practices; acknowledge the complexity of soil-farmer system interactions; and identify governance opportunities for integrated approaches to regional soil health and farmer wellbeing.