Variable rate fertilization strategies for emissions reduction: spatially resolved life cycle assessments of Canadian cereal production

Main Presenter:    Sofia Bahmutsky 

Co-Authors:   Nicole Bamber     Nathan Pelletier                                          

Nitrogen-based fertilizers have been widely used in conventional agriculture and are essential for supporting global food production (Erisman et al., 2008). The 4R nutrient management principle (right source, right rate, right time, right place) guides efficient fertilizer application to boost productivity while minimizing environmental impacts. Variable-rate (VR) technologies enable implementation of the 4R principle by allowing spatially and temporally variable application of chemicals based on crop demand, rather than uniform rates. These techniques may reduce greenhouse gas (GHG) emissions from agriculture. This study developed highly spatially resolved life cycle inventories for Canadian wheat and barley production, and conducted localized ISO 14044-compliant LCAs.

This study conducted comparative LCAs of wheat and barley produced with and without VR fertilization strategies using a central Alberta research farm as a case study. Particular emphasis was placed on utilizing highly spatially-resolved farm management records for precise primary data; soil samples and operational data were gathered over several agricultural seasons from conventionally and variably fertilized fields. The functional unit was 1 tonne of grain, and the system boundary included soil preparation, seeding, chemical inputs, and harvesting procedures. Since VR fertilization required cellular data transfer for creating and sending operational data and map files to farm machinery, information communication technologies such as internet and computer manufacturing and energy requirements were included within the system boundary. The LCAs were conducted using OpenLCA 2.5 with Ecoinvent 3.11 as the supporting background database. Environmental impacts were evaluated using ReCiPe
2016 Midpoint (H) impact assessment methods, including climate change, eutrophication, ecotoxicity, acidification, and human carcinogenic and noncarcinogenic toxicity.

Preliminary results suggest that, across most environmental impact categories, VR fertilization reduced impacts compared to conventional practice. Despite increased energy needs to implement VR practices (data transfer, software, etc.), this was outweighed by reduced fertilizer-associated impacts. Results include lower GHG emissions, reduced nutrient runoff, and improvements in climate change and toxicity indicators, supported by VR technology’s potential to optimize input use and previous studies (Medel-Jiménez et al. 2022). Additionally, differences were observed between the spatially resolved primary data and the default provincial, national, and global-scale Ecoinvent processes, especially for fuel consumption and chemical inputs. This emphasizes the importance of site-specificity when conducting LCA, especially for highly variable systems like agriculture. This research clarifies the environmental trade-offs and benefits of adopting VR practices, informing best practices for
sustainable agriculture and supporting policy decision-making.

©2026 Forum for Sustainability through Life Cycle Innovation e.V. | Contact Us | Legal Info

CONTACT US

If you would like to get in touch with us, please feel free to send us a message. Thank you very much in advance.

Sending

Log in with your credentials

or    

Forgot your details?

Create Account