Complex issues like harmful algal blooms have many causes and many impacts — which means many different people have perspectives and roles to play in finding solutions. Researchers in this focus area are figuring out how information moves through existing networks of people and how to best use those networks — such as OSU Extension and farmer partnerships — to create effective collaborations to tackle harmful algal blooms.
Projects
Impacts of Applying Drinking Water Residuals With Algal Toxins to Ohio Soils
Principal Investigator
Nicholas Basta, The Ohio State University
Project Summary
For the past decade, the agricultural community has used water treatment residuals (WTR) — the solids left behind from treating water — to help their soil. WTR contain high-quality lime materials that soften water, and farmers often apply them to land to obtain optimum soil pH for crop production. However, the harmful algal bloom toxin microcystin, removed from water when treated for consumption, may be present in this useful material. Several studies have shown that microcystin, when applied to land, can be absorbed by vegetable crops, such as lettuce and carrots, and move through soil into groundwater, potentially threatening well water safety.
Researchers studied whether applying lime residual containing microcystin to farmland could threaten crop quality or ground water. They first looked at how microcystin moves through a range of different Ohio soils in a laboratory bench study where residuals were applied to soil surfaces. The study found that soil with organic matter and clay content can absorb the toxin and reduce its movement in soil. Based on this work, farmers should consider soil type when applying WTR with high microcystin levels and avoid the practice with sandy soils.
The team then studied the toxin’s movements in actual farmland applied with residuals in Celina, Ohio, sampling corn and soybean crops across a growing season. So far, results show no uptake of microcystin into corn and soybean crops when following Ohio EPA WTR use guidelines. Applying the sludge at regulatory limits didn’t result in impaired crop quality.
Data from this study will be used by the Ohio EPA to limit threats from microcystin when lime residuals are applied to cropland. Researchers will work with the agency to refine their WTR application guidelines to protect human health.
The Bottom Line
Researchers examined what happens to algal toxins in lime residuals from water treatment plants once they’re applied to farmland. They studied how the hazardous toxin microcystin moves through soil applied with lime residual in a laboratory setting and on actual cropland. Results so far suggest that soil type can affect the toxins’ movement and that following regulatory guidelines when applying the contaminated material can prevent crop impairment. Data will help inform Ohio EPA regulatory guidelines.
Preventing Blooms by Slowing Down Water Flow on Farm Fields
Principal Investigator
Steve Lyon, The Ohio State University
Project Summary
Tile drainage systems can help farmers drain waterlogged landscapes to promote agriculture, yet researchers fear that this increases the speed at which water moves through streams, sending nutrients downstream to the Great Lakes, promoting harmful algal blooms.
Meanwhile, solutions to these concerns are emerging. Drainage water management — putting a control structure at the outlet of a tile system — can essentially “plug up” pipes to raise the water level and slow water movement when needed. Even better are automated systems with sensors that can automatically adjust the water level in fields, saving farmers time. However, researchers don’t fully understand the total impact these structures have on nutrient runoff.
Researchers assessed the impact of tile drainage and automated drainage water management on stream flows and nutrient loading. They synthesized stream flow data across Ohio to characterize the impacts of tile drainage. The team also monitored an agricultural field in Wooster to see how water and nutrients move through the landscape under automated drainage water management.
Through the project, the team found that tile drainage has a significant impact on streams in Ohio. They confirmed that streams tended to be “flashier” — they respond to rainfall very fast, with higher peak flows — due to the spread of tile drainage. Notably, researchers found that automated drainage water management can help reset these impacts by slowing water down as it moves through farm fields, reducing nutrient loading. Automated management doubled the time from peak rain to peak runoff, from around 20 hours in traditional systems to 40 hours in automated systems.
Findings from this project will help farmers make decisions around adopting drainage water management as a conservation practice. The team is collaborating with The Nature Conservancy and AgriDrain, a major drainage water management system manufacturer, to inform implementation, management and monitoring of fields with automated systems. Results are being communicated through information sessions and OSU Extension outreach as well.
The Bottom Line
Researchers confirmed that the widespread use of tile drainage systems across Ohio farmland causes streams to transport nutrients faster. However, they found that automated drainage water management can significantly reduce this by slowing water down. Results will help farmers make decisions about adopting this conservation practice.
Tracing Flow and Transport Pathways in Geographically Isolated Wetlands Using Rainwater and Ambient Temperature (RwAT)
Principal Investigator
Kennedy Doro, The University of Toledo
Project Summary
Wetlands act as buffers, absorbing and slowly releasing water into Lake Erie. New research is looking into how wetlands can be improved to prevent nutrient loading into western Lake Erie with the goal of learning how water seeps through soil within wetlands and ultimately increases the ability of wetlands to retain nutrients. To accomplish this, the team is developing a new way to trace water movement, determining what direction it moves, how much water moves, how long the water remains within the wetland and how this affects nutrient retention. Instead of tracing this movement with chemicals, researchers are testing a new method that uses rainwater and slightly heated water to show how water flows through wetland soils. The team tested this method and will implement it later this year at some selected wetlands. Results from the project will provide wetland site owners and managers with a way to improve the design of new wetlands and check the status of existing ones.
Optimizing Manure Application Timing and Soil Health Testing to Improve Water Quality Outcomes and Farmer Profitability
Principal Investigator
Leonardo Deiss, The Ohio State University
Project Summary
In farm fields, major gains in the efficiency of manure use for nutrient application require better synchrony between application and crop nutrient demand. Researchers at The Ohio State University are conducting on-farm trials in partnership with producers to measure the effects of applying manure into a growing crop in the spring versus bare soil in the fall. Preliminary results suggest that application of manure into a growing corn crop (i.e., side-dressing) could be a viable practice to improve nitrogen use efficiency and increase yield while reducing nitrate and phosphorus losses. Further, they are seeing that soil health can be used as a guide to reduce nitrogen application requirements.
Development and Implementation of Low-Cost, On-Site, Real-Time Ionic Sensors for Assessing Water Quality from Land to Lake
Principal Investigator
Laura Johnson, Heidelberg University
Project Summary
Scientists lack the technology for real-time measurements of the dissolved reactive phosphorus and forms of nitrogen that contribute to harmful algal blooms. Most sensors are unable to detect these nutrients at naturally occurring levels, are prohibitively expensive or are unable to handle other factors such as sediments and high velocity in natural waters. Researchers are developing and testing a new sensor technology that could revolutionize water quality analysis by using a relatively inexpensive smart material to analyze for ammonium and phosphate. They have developed a way to protect the sensors in the water and have deployed them in sampling locations to test the effectiveness of remote field measurements.
Evaluating Field- and Watershed-Scale Water Quality Benefits of H2Ohio Conservation Practices in the Maumee River Watershed
Principal Investigators
Asmita Murumkar, The Ohio State University
Jay Martin, The Ohio State University
Kevin Czajkowski, The University of Toledo
Project Summary
Through remote sensing and watershed modeling approaches, researchers are studying the effectiveness of the state’s H2Ohio program conservation practices in the Maumee River watershed. They are improving the watershed model representation by updating regional data including state-of-art, high-resolution crop management remote sensing data and 2017 agriculture census animal counts, animal operation locations and soil test phosphorus values. They are also calibrating for flow and water quality data using both edge-of-field and river gauge sites. Their results will inform future statewide conservation practice implementation and address Ohio Lake Erie Commission, Ohio Environmental Protection Agency and Ohio Department of Agriculture priorities to reduce phosphorus in the Maumee River basin by 40% relative to what occurred in 2008. The interdisciplinary team includes researchers from The Ohio State University, the University of Wisconsin-Madison, The University of Toledo and the U.S. Department of Agriculture’s Agricultural Research Service.
Using Novel Isotopic Methods to Differentiate Among Agricultural Inorganic Phosphate Sources and Seek Patterns of Addition Within the Grand Lake St. Marys Watershed
Principal Investigator
Melanie Marshall, Wright State University
Project Summary
While many bodies of water have been studied with regard to nutrient loading, eutrophication and the presence of harmful algal blooms, it is still relatively uncertain in most watersheds exactly where nutrients are coming from. New research in the Grand Lake St. Marys Watershed examines isotope ratios to differentiate among varying types of agricultural manures as a method of tracing the nutrient sources. The researchers also are mapping patterns of phosphate addition within a stream that empties into Grand Lake St. Marys to locate potential “hotspots” and enable more focused mitigation efforts. This study outlines a novel and emerging technology that could be used to assess variation in phosphorus sources as well as patterns across space and time, allowing for more targeted and relevant conservation efforts to reduce nutrient loading.
Quantifying Nutrient Reduction in a Constructed Wetland Complex Treating Storm Flows From East Fork Little Miami River
Principal Investigator
Ryan Winston, The Ohio State University
Project Summary
The East Fork Little Miami River contributes nutrient pollution to downstream water bodies, causing harmful algal blooms to occur. In the river’s floodplain and within a retired 3-acre drinking water reservoir, researchers have constructed an off-channel wetland to divert stormflow and remove nutrients and sediments and then return the treated water to the river. They are comparing the relative pollutant removal efficiencies of three treatment zones: a wintering pool, an attenuation wetland and a meandering treatment wetland. Data collected on this design could help inform how nutrient flows are abated, optimize their hydrologic conditions and inform their function during flooding events so that the riverine wetland complex could be mimicked along major rivers across Ohio.
Evaluation of a Modified Two-Stage Ditch Design Approach for Sediment and Nutrient Removal
Principal Investigators
Jon Witter, The Ohio State University
Dan Mecklenberg, The Ohio State University
Project Summary
Improved water drainage can affect crop production and impact watershed hydrology, channel morphology, water quality, stream habitat and aquatic biology, and new practices must be considered in planning for drainage management and conservation at the local level. Researchers are studying a floodplain construction practice, called two-stage channel design, as well as self-forming channel design, which establishes initial conditions upon which a channel or floodplain will develop over time. To date, the researchers have quantified sediment and nutrient retention in these self-forming channels. This data has been used to inform programmatic decisions for the H2Ohio program (Ohio Gov. Mike DeWine’s statewide water quality initiative), and the researchers are sharing their findings with the Ohio Lake Erie Aquatic Research Network and the Ohio Environmental Protection Agency as well as conservation networks, contractors and engineers.