Less Agricultural Phosphorus Applied in 2019 Led to Less Dissolved Phosphorus Transported to Lake Erie

• DOI: 10.1021/acs.est.0c03495
• Publication Date: 2020-12-07T07:19:18Z
• Authors: Tian Guo; Laura T. Johnson; Greg A. LaBarge; Chad J. Penn; Richard P. Stumpf; David B. Baker; Gang Shao
• Keywords: 2. Zero hunger; Agriculture; Phosphorus; 04 agricultural and veterinary sciences; precipitation; 15. Life on land; crops; 6. Clean water; Lakes; Rivers; 13. Climate action; redox reactions; 0401 agriculture, forestry, and fisheries; phosphorus; soils; Environmental Monitoring

Extreme precipitation events affect water quantity and quality in various regions of the world. Heavy 2019 resulted a record high area unplanted agricultural fields U.S. especially Maumee River Watershed (MRW). March–July phosphorus (P) loads from MRW drive harmful algal bloom (HAB) severity Lake Erie; hence changes management that influence P export can ultimately HAB severity. In this study, we found dissolved reactive (DRP) load was 29% lower than predicted, while particulate (PP) similar to predicted value. Furthermore, reduced DRP less severe based on discharge volume. The reduction loss occurred with 62% applied P, emphasizing strong recently subsequent incidental losses watershed loading. Other possible contributing factors include intensity, altered tillage practices, effects fallow soils, but more data is needed assess their importance. We recommend conservation practices focusing application techniques timing improving resiliency against extreme events.