LEAP
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Legacies of Agricultural Pollutants (LEAP): |
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Coordinator: Prof. Dr. Philippe Van Cappellen |
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Projects Partner and Institution: |
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Key words: agricultural pollutants, nutrient legacies, best management practices (BMPs), time-lags, watershed nutrient models, nitrogen, phosphorus. |
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Abstract:: Agricultural nitrogen (N) and phosphorus (P) fertilizer applications have greatly improved agricultural productivity. An unintended consequence of fertilizer use is the negative impact of nutrient enrichment on water quality and aquatic ecosystem health. Agricultural beneficial management practices (BMPs) have been implemented to combat this threat. However, the legacy stores of N and P accumulated in the landscape over decades of fertilizer application are slow to be released from the soil, hence, creating time lags between BMP implementation and measurable water quality improvements. The LEAP project addressed the scientific challenges of reconstructing the accumulation and predicting the ensuing fate of N and P legacies in contrasting agroecosystems in Canada and Europe, and then translating the newly acquired data and knowledge base into water quality risk and associated social and economic cost assessments. Nutrient input-output trajectories have been completed at the river basin scale in Canada (Grand River), Portugal (Mondego) and Sweden (Norrström) following a common protocol that enables the comparative analysis of the trajectories in terms of historical land use and agricultural practices. In addition to producing maps showing the past and present-day distributions of legacies, model calculations were performed to estimate the time scales of release of stored N and P legacies. The time lags of surface water quality recovery are typically on the order of decades. A predictive understanding of nutrient legacy source zones and transport pathways enables locating where BMPs would be most effective in reducing the release of agricultural nutrient legacies to the river network. For example, an erosional P export risk assessment was carried out for the entire province of Ontario to prioritize the implementation of soil conservation measures. To broadly assess public knowledge and perceptions about the impacts of agriculture on water quality, Q-methodology focus groups and surveys were conducted in all four countries, complemented with personal interviews and an initial online questionnaire pilot test. Based on the preliminary findings, a final questionnaire was developed and used to collect online data from over 3000 respondents in all four countries. The surveys show a remarkable convergence of people’s appreciation of the benefits of water quality improvements across the different geographies, cultures and agricultural systems. Work has also focused on integrating nutrient legacy time lags, social welfare benefits of water quality improvements and cost-effectiveness analyses, in order to guide policies and BMPs aimed at reducing the negative consequences of N and P enrichment on water quality while minimizing trade-offs. The LEAP project has yielded innovative model developments, assessment strategies and protocols that address the role of agricultural N and P legacies in water quality from a holistic, socio-ecological perspective. The comparative analyses among the four countries underscore the general applicability of these tools across variable agricultural management systems, climate conditions and affected water bodies, as well as different regulatory and social contexts. The results of the project are being broadly disseminated to end-users including regulatory authorities and agencies, and farmer and environmental organizations in Europe and Canada. The project’s research products, including a webinar series summarizing the analytical capabilities and major findings of LEAP, can be found on the website: |
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Project structure: The organizational structure includes: the management committee (includes WP leads and consortium coordinator), the project office, and an external advisory committee.
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Implementation:
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Outcome/deliverables: |
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References coordinator and leaders of each WP: |
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Main outputs
More results on the project: Data and resources |
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Contact Point for Communication/Dissemination activities: Tatjana Milojevic (tatjana.milojevic@uwaterloo.ca) |
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Contact Point for Open Data/Open Access activities:Tatjana Milojevic (tatjana.milojevic@uwaterloo.ca) |
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