Evaluating the 4R Nutrient Stewardship Concept and Certification Program in the Western Lake Erie Basin

The increase in harmful algal blooms in Lake Erie since the mid-1990s is correlated with an increasing trend in dissolved phosphate loading. This multi-disciplinary research project, initiated in July 2014 with an end date of June 2019, aims to quantify the water quality benefits of 4R initiatives in the Western Lake Erie Basin (WLEB). As of January 2018, 37 retail locations reaching almost two million acres, had achieved certification in 4R Nutrient Stewardship. There remains a need to better understand and quantify the water quality benefits of the 4R program.

The 2017 efforts of this project included five objectives:

(1) Edge-of-field (EOF) monitoring: Water quality data was collected from 20 paired sites comparing 4R and other crop and soil management practices. Collaborators prepared over 40 presentations summarizing EOF data. Several peer-reviewed articles indicated that shifting from broadcast to subsurface placement of phosphorus (P) fertilizer (“right place”) will limit stratification and has potential to limit dissolved P leaching in tile-drained landscapes.
(2) Watershed monitoring: Preliminary analysis comparing 4R certification to corresponding watershed nutrient export data was initiated. Monitoring data was summarized in over 25 presentations.
(3) Watershed modeling: The SWAT model was expanded to include nine paired sites (18 fields). An additional suite of BMP scenarios with a 4R focus (specifically placement and timing) were integrated into the model.
(4) Lake ecosystem modeling: A sensitivity analysis was conducted using the Western Lake Erie Ecosystem Model to explore the impact of algal growth and sediment-related parameters on predicted cyanobacteria biomass.
(5) Socio-economic surveys: Survey results were published in a technical report titled “4R Nutrient Stewardship in the Western Lake Erie Basin.” A producer survey was sent out to assess knowledge and adoption of 4R practices. A video was produced highlighting the 4R initiative and promoting the benefits of subsurface placement.