One size does not fit all: Toward regional conservation practice guidance to reduce phosphorus loss risk in the Lake Erie watershed


Macrae, M., Jarvie, H., Brouwer, R., Gunn, G., Reid, K., Joosse, P., King, K., Kleinman, P., Smith, D., Williams, M., Zwonitzer, M. (2021). One size does not fit all: Toward regional conservation practice guidance to reduce phosphorus loss risk in the Lake Erie watershed. Journal of Environmental Quality, [online] 50(3), 529-546.

Plain language summary

Phosphorus loss from agricultural land is one of the drivers of water quality impairment by algae blooms in lakes and reservoirs, so it is important for farmers to adopt appropriate best management practices (BMPs) to reduce this loss. Many practices are recommended, but the effectiveness of each practice varies from place to place and implementing the wrong practice can actually increase losses. Ideally, the choice of practices would be tailored to the conditions in each field but this is complex and not easily captured in policies to encourage BMP adoption. In the Lake Erie watershed, the soils, topography and climate vary from the flat clay plains at the southwest end of the watershed to the rolling topography and loamy soils in the northeast. Narrowing the range of recommended practices to suit the dominant conditions in each region will increase the effectiveness of the BMPs and use resources more efficiently.


Agricultural phosphorus (P) losses to surface water bodies remain a global eutrophication concern, despite the application of conservation practices on farm fields. Although it is generally agreed upon that the use of multiple conservation practices (“stacking”) will lead to greater improvements to water quality, this may not be cost effective to farmers, reducing the likelihood of adoption. At present, wholesale recommendations of conservation practices are given; however, the application of specific conservation practices in certain environments (e.g., no-till with surface application, cover crops) may not be effective and can even lead to unintended consequences. In this paper, we present the Lake Erie watershed as a case study. The Lake Erie watershed contains regions with unique physical geographies that include differences in climate, soil, topography, and land use, which have implications for both P transport from agricultural fields and the efficacy of conservation practices in mitigating P losses. We define major regions within the Lake Erie watershed where common strategies for conservation practice implementation are appropriate, and we propose a five-step plan for bringing regionally tailored, adaptive, and cost-conscious conservation practice into watershed planning. Although this paper is specific to the Lake Erie watershed, our framework can be transferred across broader geographic regions to provide guidance for watershed planning.

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