What do we know about the effectiveness of Best Management Practices (BMPs) in reducing phosphorus losses from cropland in the Western Lake Erie Basin? Answering that question was the focus of a conference March 9-10 of this year, organized by the Partnership for Ag Resource Management and hosted by the National Center for Water Quality Research at Heidelberg University. Funding was provided by the USDA Natural Resources Conservation Service Conservation Innovation Grant program.
Research suggests that an approximately 40% reduction in phosphorus loading would reduce the frequency and severity of western Lake Erie algal blooms to acceptable levels, i.e., few and mild when they occur. The International Joint Commission, an international body formed by the US and Canada in 1909 to help manage the boundary waters between the two countries, has set a goal for restoring the health of the Great Lakes by 2022, thus making the conversations that took place at the conference both essential and timely.
Expert presenters and 85 conference participants reviewed current knowledge and developed research priorities to fill gaps in our understanding.
Dr. Laura Johnson, director of the Heidelberg Center, reviewed what we know about phosphorus movement in the Watershed from water samples collected by monitoring stations operated by the Center. She also presented data on concentrations
of phosphorus in upper layers of soil, resulting from years of surface applications and limited tillage. This concentration can increase potential for phosphorus losses during precipitation and snow-melt events.
Dr. Libby Dayton, Ohio State University, reported on progress towards an improved phosphorus index for Ohio. The index can be used by farmers and others to estimate potential for phosphors losses from individual fields. Dr. Kevin King, research leader with the USDA Agricultural Research Service, reported on early results from studies looking at phosphorus concentrations in surface runoff and drainage tile effluent from 20 paired sites, each with different farming practices in place. His research suggests that shallow (3") tillage incorporation of phosphorus after surface applications may reduce phosphorus losses by four fifths.
The afternoon session also included a demonstration of the Nutrient Tracking Tool (NTT), an online resource developed by Dr. Ali Saleh and colleagues at the Texas Institute for Environmental Research at Tarleton University in Texas. NTT users can compare different management practices to approximate how each practice will impact crop yield, and whether it will improve soil health protect water quality. Dr. Rem Confesor, senior scientist at the Heidelberg Center, is collaborating with Dr. Saleh to adapt NTT for conditions in the Western Lake Erie Basin, and to test and refine its predictions for fields in the region.
On day two, Dr. Robyn Wilson, associate professor at The Ohio State University, shared data she has developed on farmer perceptions of, and likeliness to adopt specific BMPs. Her findings indicate that there is strong interest in both cover crops and subsurface placement of phosphorus. Growth in adoption by farmers can be supported by clearly communicating the efficacy of specific BMPs, and maintaining programs that help cover additional costs incurred by farmers.
Attendees agreed that common messages, communicated by everyone working to improve western Lake Erie water quality, were needed to generate focused, effective changes in practices and sustainable improvements in water quality. Challenges include as-yet-unresolved uncertainty around efficacy of potentially key BMPs, and unmet technology needs. For example, cover cropping impacts on phosphorus losses have not been conclusively demonstrated, and the large variability in the practice, including differences in cover crop species, timing and method of planting and termination, and in weather conditions from year to year, make research a costly and lengthy endeavor. Equipment to affordably place phosphorus under the soil surface, without increasing soil erosion, is also lacking.
Videos of the presentations from all speakers will be available shortly on our website!
We will alert you as soon as they are posted.