Lake Erie, the shallowest and warmest of the Great Lakes, has been increasingly threatened by eutrophication and harmful algal blooms affecting economic growth in the region. Excess nutrients, particularly phosphorus, transported with agricultural runoffs have become a major issue of lake water quality. In response to this growing concern over the adverse environmental effects of agriculture, farmers, conservation authorities and governments have worked together to promote and implement best or beneficial management practices (BMPs) in the contributing watersheds that focus on maintaining agricultural activity and farm profitability while protecting the environment. This paper conducted a technical review of BMPs and their effectiveness on phosphorus load reduction from agricultural fields for the Canadian Lake Erie Basin (CLEB). These BMPs include cover crop, conservation tillage, manure incorporation, crop nutrient planning, fragile land retirement, adding organic amendments, reducing soil compaction, controlled tile drain, grassed waterway, vegetative filter strip, riparian buffer, water and sediment control basin, and wetland restoration. Field experiments and modeling studies about BMP effectiveness on phosphorus load reduction from agricultural fields in the CLEB and the Great Lakes region were reviewed and assessed. Findings from other similar geographic regions were also documented for comparison and reference. Because BMPs are site-specific, their phosphorus load reduction effectiveness varied over a wide range in the literature depending upon characteristics of the BMP and local climate, slope, soil type, land use, and land management conditions. Based on the literature review, factors influencing BMP effectiveness were analyzed, and suggestions on research priorities for evaluating BMP effectiveness in the CLEB were provided. This study will benefit decision-makers, watershed conservation authorities, and other stakeholders in estimating phosphorus load reductions from agricultural landscapes and contribute to tracking progress toward achieving Canada’s phosphorus load reduction targets for Lake Erie.
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