Tuesday, July 11th, 2017
Data reveal winter manure application ban reduces runoff
By Nancy Allen
MARIA STEIN - The ban is working.
Data show a ban on wintertime manure application has reduced nutrient runoff from the Chickasaw Creek subwatershed into Grand Lake.
"This is a good thing," said Stephen Jacquemin, Wright State University-Lake Campus associate professor, who helped analyze the data collected by Heidelberg University at a water-monitoring station on the creek. "Once these results are published, they have the opportunity to take on a larger importance to a regional level and perhaps a global level."
Jaquemin spoke during Monday's Ag Solutions meeting.
The ban restricts manure application from Dec. 15-March 1 and is one of several rules livestock farmers in the Grand Lake Watershed must follow after the state declared the watershed distressed on Jan. 18, 2011. Manure, which contains phosphorus and nitrogen, is more prone to run off into water bodies during rain and snow and ice melt events. Though algae feed on both phosphorus and nitrogen, phosphorus is the algae's favorite food source.
Jaquemin said baseline data on flow, nutrients and total suspended solids were gathered from 2008 to 2011 in the Chickasaw Creek subwatershed before the ban began. Data were then gathered after the ban went into effect - from December 2011 through October 2016.
Results show that during this six-year period, particulate phosphorus dropped 55 percent during high flows, 57 percent during medium flows and 46 percent during low flows. Dissolved reactive phosphorus decreased 48 percent during low flows, 28 percent during medium flows and 18 percent during low flows. Nitrate levels decreased 1 percent during low flows, 16 percent during medium flows and 19 percent during high flows. Particulate phosphorus is bound to some sort of sediment, clay or manure while dissolved reactive phosphorous is dissolved in water, Jaquemin said.
Dissolved reactive phosphorus is most readily available for uptake by algae. Nitrates are a type of nitrogen.
Jacquemin said more study is needed, particularly in how dissolved reactive phosphorus gets into water bodies. He said less is known about this type of phosphorus.
State agriculture engineer Terry Mescher, who also helped analyze the data, agreed.
"We don't have a lot of tools in our toolbox to control DRP," he said. "It didn't become part of my lexicon until about seven years ago."
Jacquemin said the results are promising.
"Grand Lake has incredibly high nutrient levels, but now we have a process in place to reduce that," he said. "This is a great step in the right direction."
Phosphorus-fed toxic blue-green algal blooms have resulted in state-issued water advisories on Grand Lake every year since 2009 and reportedly millions of dollars in lost tourism on the 13,500-acre lake. The lake has been under a no-contact advisory since July 2016 due to unsafe algal toxin levels. Grand Lake is the only water body in Ohio with the distressed designation. Nutrient runoff comes from many sources, but in the Grand Lake Watershed, studies show it's mostly from farmland in the 58,000-acre, livestock-heavy watershed.
Others helping analyze the data include Ag Solutions Coordinator Theresa Dirksen; Lake Campus agriculture program coordinator Greg McGlinch; and Laura Johnson, director of the National Center for Water Quality Research at Heidelberg University in Tiffin.
Jaquemin's full PowerPoint presentation on the Chickasaw Creek subwatershed results will be posted on the Ag Solutions and Lake Improvement Association websites by the end of the week.
While the Chickasaw Creek subwatershed was the only area studied, Jacquemin said the results are likely similar throughout the entire watershed.
"You could extrapolate the data to the whole watershed," he said. "While we used it as our study area, the Chickasaw Creek subwatershed is representative of what is going on in the Grand Lake Watershed as a whole."
Also during Monday's meeting, Victor Van Slyke, president of ATD Waste Systems, Vancouver, British Columbia, Canada, discussed his company's manure separation system. The system was designed around the need to reduce fresh water consumption, improve air quality for animals and staff and conserve nutrients by daily collection of manure and treatment as well as the need to expand production without increasing acres.
Attendees also heard Dirksen report that,
• Ag Solutions has received a $6,170 Ohio Farm Bureau grant that will be used to study the soil health differences in no-tilled and conventional tilled fields. This will be done through satellite imaging, thermal imaging and soil health laboratory testing. Roughly 600 acres will be studied during this growing season and next. A field day will be held in the fall of 2018 to share the findings. The $15,370 project will also include $9,200 in local, in-kind matching funds.
• Ag Solutions and the Mercer County Soil and Water Conservation District has received tentative approval for a $25,083 grant from the Great Lakes Sediment and Nutrient Reduction Program to construct an in-line series of conservation practices through a concentrated flow area in the St. Marys River Watershed. Construction would begin in 2018. The $34,431 project also would include $9,348 in local in-kind matching funds. Final awards should be announced by Sept. 1, and work on the projects can begin Oct. 1.