Research HighlightsMeasuring Fall Cover Crop Impacts on Watersheds in Indiana
By Barb Baylor Anderson
Soybean farmer use of fall cover crops continues to rise, which has made investigation of their impact on local watersheds of interest to researchers. The Beargrass Creek Experimental Watershed Research Initiative is one of the longest running watershed research initiatives in Indiana focused on the effect of soil and water conservation practices relative to nutrient and sediment loads, stream ecological integrity and building conservation partnerships with farmers.
“Reduction in soil and nutrient loss, along with improving soil health, has been the focus of our research. It has been a wildly successful initiative at many levels,” says Jerry Sweeten, senior stream ecologist, Ecosystems Connections Institute, Denver, Indiana, and professor emeritus of biology and environmental studies, Manchester University. Sweeten was the principal investigator for the six-year project funded by the Indiana Soybean Alliance and local farmers. “This long-term research has illuminated new patterns and trends in data.”
“Investing checkoff dollars in crop production research is one of the best things farmers can do for themselves,” says C.J. Chalfant, Indiana Soybean Alliance board member who farms near Hartford City. “In the past 20 years, soybean yields in Indiana and across the Midwest have seriously improved. Most of the improvement has come through better practices and technologies that have come through crop production research. I think we’ve only scratched the surface of what is possible. I believe the more research we do, the more bushels we will find.”
The upper portions of the Beargrass Creek Watershed (cover crops treatment) and the upper portions of the Pawpaw Creek Watershed (control for comparison) in Wabash County, Indiana, were chosen for the research. Beargrass Creek joins the Eel River in northern Indiana and has a watershed of 14,758 acres with more than 85 percent cultivated cropland and a significant pork production presence. Most of the streams and all tributaries in the watershed have been modified into classic agricultural drainage channels with miles of subsurface drains across the watershed.
The project uses automatic water samplers and other technologies to determine nutrient and sediment loads and how they change with the implementation of best management practices. Researchers also monitor the fish and invertebrate communities. The Indiana soybean checkoff investment was leveraged for other grants to build a 1,500 foot, two-stage ditch for observation. Researchers built a prototype fish ladder around a mill dam in the Eel River and reintroduced a Federally Endangered mussel that now has a greater than 95 percent survival rate.
“Since beginning in 2014, we have analyzed more than 6,000 water samples for nutrients and sediment and surveyed fish and stream habitat each year,” says Sweeten. “While results continue above target values, we documented a general decrease in nutrient and sediment loads and an increase in fall cover crop use and other best management practices. We also documented an increase in fish index scores that measure biotic integrity in watersheds.”
Work in 2020 was conducted with funding from Wabash County Soil and Water Conservation District, Wabash County Community Foundation, Ecosystems Connections Institute and farmers.
“Six years of data is less than a radar blip in nature time to provide scientifically derived water quality data in response to voluntary soil and water conservation practices. But it is a start to illuminate responses to new and innovative management approaches,” says Sweeten. “Clean water and healthy streams in an agricultural landscape are not mutually exclusive, but the pathway forward requires time, relationship building, good science and financial support. There is so much more work that could be accomplished yet with additional funding.”
To find research related to this Research Highlight, please visit the National Soybean Checkoff Research Database.