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ARS Home » Plains Area » Temple, Texas » Grassland Soil and Water Research Laboratory » Research » Publications at this Location » Publication #335549
Title: Lake Erie, phosphorus and microcystin: Is it really the farmer's fault?

Author
item Smith, Douglas
item WILSON, R - The Ohio State University
item King, Kevin
item ZWONITZER, M - Texas Tech University
item MCGRATH, J - University Of Kentucky
item Harmel, Daren
item Haney, Richard
item JOHNSON, L - Heidelberg University

Submitted to: Journal of Soil and Water Conservation
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 3/9/2017
Publication Date: 1/1/2018
Citation: Smith, D.R., Wilson, R., King, K.W., Zwonitzer, M., McGrath, J.M., Harmel, R.D., Haney, R.L., Johnson, L. 2018. Lake Erie, phosphorus and microcystin: Is it really the farmer's fault? Journal of Soil and Water Conservation. 73(1):48-57.

Interpretive Summary: Concentrations of toxins produced by harmful algae blooms in Lake Erie are strongly correlated with agricultural phosphorus (P) loading from tributaries. Despite farmers’ efforts to reduce sediment-bound P loadings and fertilize using current guidance, the media and public have singled them out as the culprit in Lake Erie re-eutrophication. In this paper, two farmer surveys were used to evaluate if farmers in the Lake Erie region follow P fertilizer recommendations, and we also reviewed historic and current P management guidance provided by the scientific community and agricultural industry. The majority (56-80%) of farmers apply P fertilizers at or below the current fertility recommendations. Wholesale agronomic changes (e.g., no-tillage adoption, crop cultivar advances, fertilizer application and formulation) have occurred since current fertilizer recommendations were developed. Although crop P uptake mechanisms have not changed, these agronomic changes have altered P cycling in soil and water. Based on these results, it is time that the scientific community and agricultural industry acknowledge that our current guidance may be contributing to eutrophication. We must ask whether or not we have: 1) developed appropriate fertility guidance; 2) developed and recommended appropriate practices to protect water quality; 3) adequately considered “the law of unintended consequences” in conservation recommendations; and 4) focused too much on short-term economic outcomes while disregarding environmental quality. Improved understanding, reconsideration of traditional recommendations, and wider farmer adoption of the most effective practices are needed to develop a sustainable agricultural system in the Western Lake Erie Basin that produces needed commodities while protecting the environment.

Technical Abstract: Agricultural loss of phosphorus (P) have been identified as a primary contributor to eutrophication and the associated release of toxins (i.e., mycrocystin) in Lake Erie. These losses are commonly deemed excessive by the media and the public, singling out agriculture as the culprit in spite of reductions in erosion and associated sediment bound-P losses and widespread implementation of P fertility recommendations. This paper describes the evaluation of how many farmers in the Lake Erie region follow P fertilizer recommendations based on two farmer surveys, and itreviews historic and current P management guidance provided by the scientific community and agricultural industry. The farmer surveys showed that 56-80% of farmers apply P fertilizers at or below the current fertility recommendations. Wholesale agronomic changes (e.g., no-tillage adoption, crop cultivar advances, fertilizer application and formulation) have occurred since current fertilizer recommendations were developed. Although crop P uptake mechanisms have not changed, these agronomic changes have altered P cycling in soil and water. Based on the survey findings and agronomic changes, it is time that the scientific community and agricultural industry acknowledge that current guidance may be contributing to eutrophication. Have we: 1) developed appropriate fertility guidance; 2) developed and recommended appropriate practices to protect water quality; 3) adequately considered “the law of unintended consequences” in conservation recommendations; and 4) focused too much on short-term economic outcomes while disregarding environmental quality. Improved understanding, reconsideration of traditional recommendations, and wider farmer adoption of the most effective practices are needed to develop a sustainable agricultural system in the Western Lake Erie Basin that produces needed commodities while protecting the environment.