Cover crops and water quality webinar preview #1

On February 16, 2022, the Discovery Farms® Programs in Wisconsin, Vermont, Arkansas, and Minnesota will host a one-day webinar titled “Cover crops and water quality.” Join this interactive webinar to learn more from what water quality monitoring across these four states has shown on fields with planted cover crops. 

This 3-hour webinar will begin at 9:00 am Central Time and 10:00 am Eastern Time. CEUs will be available. Please register for this free webinar at: 

The Discovery Farms® Program was founded in Wisconsin in 2001 with the task to partner with farmers to collect on-farm water quality data around the state and extend that information so that others could understand the impact of practices, and, if needed, adapt and adopt specific solutions to water quality challenges. Discovery Farms Programs are active in Wisconsin, Minnesota, Vermont, and Arkansas. Each Discovery Farms Program is built on three pillars including: 

Farmer leadership

On-Farm, water quality research

Communication of results

Read on for part one of an article series that will preview presentations to be given during the webinar on February 16, 2022. 

The first Discovery Farms Program

In Wisconsin, the Discovery Farms Program is a part of the University of Wisconsin-Madison Division of Extension. Discovery Farms provides unbiased research results and educational opportunities to audiences about the relationship between agriculture and water quality. For the last twenty years in Wisconsin, Discovery Farms has stayed true to its roots by 1) partnering with farmers to determine research priorities and decision making 2) conducting research on privately owned farms throughout the state, and 3) communicating results in a timely and effective manner. The program is led by a Steering Committee which is made up of representatives from all of the major agricultural organizations, agencies, and environmental organizations in Wisconsin. 

Surface water and phosphorus contamination have traditionally been the main water quality concern in surveys done in Wisconsin. Algal blooms in lakes, and the degradation of water quality in streams and rivers raise challenges between agricultural production and environmental protection. The surface water quality data collected by Discovery Farms is useful for farmers that are continuing to improve farming systems and striving to reduce the loss of valuable nutrients and soil and protect water quality. These efforts aid in keeping Wisconsin a beautiful place to live and visit while maintaining a productive agricultural industry.

Typical Discovery Farms monitoring stations are located in a concentrated flow area where water is exiting an agricultural field. Surface water runoff is quantified, collected, and sent to a lab to be analyzed for phosphorus, nitrogen, and sediment. Currently, in Wisconsin, there are 9 of these surface edge of field monitoring stations located in 4 counties throughout the state. Discovery Farms utilizes local partners from Land Conservation Departments, crop consultants, farmer-led watershed groups, and Extension Educators to collect water quality samples and maintain sites year-round. Partnerships help expand research into more areas of the state and boost the sharing of results at local, regional, and statewide scales. 

There are increasing concerns about the loss of nitrogen and groundwater quality in Wisconsin. Two projects have been added to the Discovery Farms list including a Nitrogen Use Efficiency Project and a Nitrogen Leaching Project. The Nitrogen Use Efficiency Project began in 2015 with the goal to assess N utilization on a per-field basis. This project has worked with over 80 farmers across Wisconsin to evaluate how efficiently nitrogen is managed and what the potential economic and environmental impacts of N management may be. The Nitrogen Leaching Project is the newest style of project added to the Discovery Farms portfolio. Pan lysimeters are utilized to capture water that flows beyond the root zone into groundwater. This water is collected and analyzed. We are just beginning to tap into what we can learn about nitrogen and the potential for farm management decisions to mitigate losses to groundwater. 

Cover crops and water quality

Over the last several years, there has been a growing interest in cover crops and their utilization as a conservation practice. They are a popular recommendation for farmers interested in protecting soil from erosion and retaining soil nutrients. Discovery Farms and other Wisconsin research programs are collecting data in order to quantify the impact of cover crops on water quality.

A popular practice amongst dairy farmers in Wisconsin is to plant an overwintering cover crop, such as winter rye, following corn silage. Corn silage is harvested in late summer/early fall and leaves the soil bare as the entire plant is taken from the field. This bare soil is vulnerable to erosion if not protected. Planting a rye cover crop that establishes quickly and relatively easily before the winter freeze-up is one way to protect soil in the fall, as well as the next spring as winter rye will stay alive under snowpack during a typical Wisconsin winter. 

From Discovery Farms studies, the scenarios when cover crops could have the most influence on nutrient and sediment losses include: spring and early summer when soil loss is likely to occur, fall to protect soil and scavenge nitrogen, and while the soil is frozen during winter to decrease dissolved phosphorus losses from no-till systems.

University of Wisconsin-Madison Soil Science Department Professor Matt Ruark is the Discovery Farms Wisconsin Faculty Advisor. He has performed multiple studies on cover crops, manure, and nitrogen management in relation to water quality. With the prevalence of dairy farms in Wisconsin, manure is a popular source of nutrients for cropping systems. These nutrients are vulnerable to loss if not applied appropriately. Cover crops may be able to hold on to nutrients for their later use that would otherwise be lost. 

Dr. Ruark’s work shows cover crops have the ability to provide ground cover, and also have potential to protect groundwater by trapping excess N from leaching into groundwater or tile drains. His research found that there was 40 lb/ac less plant-available N (includes both ammonium and nitrate N) in the soil when a winter rye cover crop was established vs no cover crop planted. If there is less N in the soil, this means N is “trapped” in the rye biomass and is unable to wash out of the field or leach into groundwater. Like any crop, cover crops need to be managed appropriately in order to receive these, along with other benefits. 

Join us on February 16 as we dive deeper into this discussion on cover crops and water quality.

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