Thesis Defence: Benchmarking the environmental impacts of Okanagan apple production under bark mulching with reduced irrigation and herbicide needs through life cycle assessment, based on the European Union’s Product Environmental Footprint methods

Jared Brown, supervised by Dr. Nathan Pelletier, will defend their thesis titled “Benchmarking the environmental impacts of Okanagan apple production under bark mulching with reduced irrigation and herbicide needs through life cycle assessment, based on the European Union’s Product Environmental Footprint methods” in partial fulfillment of the requirements for the degree of Master of Science in Interdisciplinary Graduate Studies – Sustainability theme.

An abstract for Jared Brown’s thesis is included below.

Defences are open to all members of the campus community as well as the general public. This examination will be offered in hybrid format.  Registration is not required to attend in person, but please email nathan.pelletier@ubc.ca to receive the Zoom link for this defence.

Abstract

Food systems significantly contribute to environmental impacts, necessitating the implementation of sustainable practices. However, these practices must provide economic opportunities to support their adoption. In the Okanagan apple industry, establishing Product Environmental Footprint (PEF) benchmarks and assessing the potential of bark mulching to reduce irrigation and herbicide needs, and accrue soil organic carbon (SOC) may provide environmental and economic opportunities for growers. However, PEF benchmarks have not been previously established for Canadian agriculture, and it is unclear if bark mulching with reduced irrigation and herbicide use, and SOC accrual can lower net environmental impacts. This thesis reports research undertaken to apply the PEF methodology to Okanagan apple production and to assess the impacts of bark mulching with SOC accrual and both reduced irrigation and herbicide needs. Both research objectives were fulfilled using life cycle assessment (LCA): a sustainability management method that assesses environmental impacts from a supply-chain perspective. LCA models of Okanagan apple production with and without bark mulching were developed with primary data from growers, Agriculture and Agri-Food Canada, and secondary data for upstream supply-chain activities that occur prior to on-orchard operations. PEF benchmarks were established for Okanagan apple production. However, most of the PEF-compliant secondary data used to model upstream activities were based on broad geographies that may not necessarily reflect the upstream environmental impacts of food systems in Canada. Bark mulching resulted in lower ecotoxicity and water use impacts compared to production without mulch, with most other environmental impacts being comparable between the two practices. However, some environmental impacts such as land use and photochemical ozone formation were significantly higher under bark mulching and SOC accrual had minimal effects on climate change impacts. These results support further developing the PEF methodology to include more secondary data with specific geographies outside of Europe and to explore how bark mulching affects fertilizer needs and economic costs. This research also highlights the importance of LCA for assessing the feasibility of novel management practices (NMPs) for woody perennial crops and the need for data on how NMPs affect environmental impacts, orchard inputs, and production costs to support conducting LCAs on NMPs.