Mackinaw River Watershed

Cover crop research began at the farm in 2011, funded in part by an Illinois NRCS Conservation Innovation Grant to monitor the effectiveness of cover crops in sequestering nutrients and reducing tile nutrient runoff. This research helps to increase our understanding of the effectiveness of cover crops for sequestering nutrients as a single practice, as well as how effectiveness might be increased by stacking cover crop practices with constructed wetlands.

Farmers are increasingly realizing the benefits of cover crops, typically oats, radish and cereal rye, which in addition to improving the health of the farmer’s soil also help keep soil and nutrients in the field and out of nearby freshwater resources. Typically planted in the late summer or early fall, they germinate and grow through to the first frost and in many cases reemerge the following spring, stabilizing soil with their roots during the winter and early spring months—but that’s not all. They also replenish important nutrients, and they can help control pests and weeds. As the cover crops decompose in the field, they also add beneficial organic matter to the land that further increases soil health.

Wetlands function as nature’s kidneys, removing nutrients and sediment as well as slowing down the flow of water before it reaches creeks, streams and rivers. When placed near agricultural lands, constructed wetlands can catch and absorb nutrients from farm fields. 

In 2003, wetlands were constructed in the cropland area of the Franklin Farm, along with seven acres of floodplain and upland wetland habitat near Turkey Creek, totaling 13.3 acres. A long-term study on these wetlands has helped researchers and farmers understand how effective constructed wetlands can be, and specifically the size and amount needed to help clean nutrients from water that passes through tile drain systems. The wetlands have proven to be very effective at reducing nitrate-nitrogen and dissolved phosphorus export from agricultural tiles that would otherwise be entering directly into the Mackinaw River. Since 2005, many wetland plants have also emerged voluntarily, including blue lobelia, broadleaf arrowhead, smartweed and water plantain.

Prairies, savannas and floodplains are all habitats that were once prevalent throughout Illinois before their acreage was reduced to make way for agriculture and development. The team at the Franklin Demonstration Farm has worked hard to restore these natural areas to the benefit of local birds, plants and wildlife. Habitat restoration at the farm includes a 14-acre native prairie planted and tended by the farm operator, Tim Lindenbaum, and underbrush removal within a remnant oak-hickory savanna conducted by students from Illinois State University under the guidance of TNC’s Krista Kirkham. 

In addition to research, outreach is an important part of the work that happens at the Franklin Demonstration Farm. Farmers and landowners are interested in seeing how conservation practices are implemented and how they work on the ground without negatively impacting their bottom lines. Tours of the Franklin Demonstration Farm help these and other members of the agricultural community see firsthand how conservation practices such as restored wetlands and grassed waterways function on working farms and how they can be economically feasible.