|JOHNSON, LAURA - Heidelberg University, Ohio|
|LABARGE, GREGORY - The Ohio State University|
|Fausey, Norman - Norm|
Submitted to: Journal of Environmental Quality
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/23/2017
Publication Date: 3/17/2017
Publication URL: https://handle.nal.usda.gov/10113/5927831
Citation: King, K.W., Williams, M.R., Johnson, L.T., Smith, D.R., LaBarge, G.A., Fausey, N.R. 2017. Phosphorus availability in Western Lake Erie Basin drainage waters: legacy evidence across spatial scales. Journal of Environmental Quality. 46:466-469.
Interpretive Summary: Inland waters worldwide continue to be plagued by harmful and nuisance algal blooms, a result of excess phosphorus. In the case of Lake Erie, the amount of phosphorus application has remained constant or decreased; yet, the dissolved fraction entering the lake is increasing. In 2015, successive large rainfall events occurred in the basin in June and July leading to the largest in-lake algal bloom on record. Across three spatial scales it was determined that phosphorus was persistent in drainage waters, even after successive large rainfall events and emphasizes the importance of legacy phosphorus in determining nutrient loading. More holistic soil tests and recommendations based on those findings will result in more efficient phosphorus use and less off-site transport.
Technical Abstract: The Western Lake Erie Basin (WLEB) was inundated with precipitation during June and July 2015 (2-3× greater than historical averages), which led to significant nutrient loading and the largest in-lake algal bloom on record. Using discharge and concentration data from three spatial scales (0.09 km2 to 16,000 km2), we contrast the patterns in nitrate (NO3-N) and dissolved reactive phosphorus (DRP) concentration dynamics and discuss potential management implications. Across all scales, NO3-N concentration steadily declined with each subsequent rainfall event, as it was flushed from the system. In contrast, DRP concentration remained persistent, even on soils at or below agronomic P levels, suggesting that legacy P significantly contributes to nutrient loads in the WLEB. Findings highlight the need to revisit current P fertility recommendations and soil testing procedures in order to increase efficiency of P fertilizer resources and more holistically account for legacy P.