Choosing an Edge-of-Field Practice: Decision Trees Can Help

Using decision trees to help determine suitable edge-of-field practices was the topic of the Iowa Learning Farms webinar yesterday. Chris Hay, Sr. Manager—Production Systems Innovation with Iowa Soybean Association, explained the basics of edge-of-field practices and discussed decision trees that can help farmers, landowners and conservation professionals select an edge-of-field practice.

Bioreactors were one of the practices Hay discussed in the webinar (image from Hay’s presentation)

Hay gave an overview of wetlands, saturated buffers, bioreactors, and controlled drainage. He explained how they can be used to address environmental concerns while maintaining agricultural productivity. These edge-of-field practices are effective at reducing nitrogen loss from agricultural fields, while also being very cost effective. This makes them an attractive choice for some landowners, but deciding which practice works for their site and their goals can be difficult.

Nitrogen loss reduction effectiveness of various practices, with the edge-of-field practices in blue (image from Hay’s presentation)

The decision trees were developed as part of the Whole Farm Conservation Best Practices Manual. The full manual is available as a free download from the ISU Extension Store or our website The tools are divided into two sets: one for farmer/landowner decision makers and one for conservation professionals. Hay explained the how the tools work and what considerations they take into account to help guide decision makers through the process of choosing an edge-of-field practice.

Hay explained how to use the decision trees to help guide decisions about edge-of-field practices (image from Hay’s presentation)

To learn more about edge-of-field practices, their performance, and how to use the decision trees in the Whole Farm Conservation Best Practices Manual to help guide conservation decision, watch the full webinar here!

Join us next week for the webinar “The Halo Effect: Do Short-Term Watershed Project Successes Lead to Long-Term Continued Successes?” presented by Jamie Benning and Dr. Jacqueline Comito, both with Conservation Learning Group.

Hilary Pierce

October 7 Webinar: Choosing an Edge-of-Field Practice: Decision Trees Can Help

Iowa Learning Farms will host a webinar on Wednesday, October 7 at noon about using decision trees to help choose an edge-of-field practice.

Edge-of-field practices, such as bioreactors, saturated buffers and wetlands, can effectively address water quality concerns, but it is important to select the right practice for your site and goals.

Chris Hay, Sr. Manager—Production Systems Innovation with Iowa Soybean Association, will cover the basics of edge-of-field practices and some of the siting considerations for the different practices during this webinar. Hay will also discuss decision trees that can help farmers, landowners and conservation professionals select an edge-of-field practice.

The decision trees were developed as part of the Whole Farm Conservation Best Practices Manual. The full manual is available as a free download from the ISU Extension Store or our website

“Edge-of-field practices are some of the best performing water quality practices, but it can be confusing to know what practices will work at a particular site,” said Hay. “These newly developed decision trees can help both farmers and conservation professionals select edge-of-field practices that best match their situation.”   

To participate in the live webinar, shortly before 12:00 pm CDT on October 7:

Click this URL, or type this web address into your internet browser:

    Or, go to and enter meeting ID: 364 284 172 

Or, join from a dial-in phone line:

    Dial: +1 312 626 6799 or +1 646 876 9923

    Meeting ID: 364 284 172

The webinar will also be recorded and archived on the ILF website, so that it can be watched at any time. Archived webinars are available at

A Certified Crop Adviser board-approved continuing education unit (CEU) has been applied for, for those who are able to participate in the live webinar. Information about how to apply to receive the credit (if approved) will be provided at the end of the live webinar.

Hilary Pierce

Is a Bioreactor Right for You?

The third practice in the Whole Farm Conservation Best Practices manual that uses the denitrification process to reduce nitrate loss is bioreactors.

Bioreactors treat water from subsurface drainage systems by diverting tile flow into an excavated trench filled with woodchips. The woodchips provide carbon and attachment surfaces for microbial communities that convert nitrate-nitrogen to nitrogen gas – which makes up the majority of our atmosphere.  The graphic below illustrates how the water flows through the woodchips using control structures on the inlet and outlet of the bioreactor.

Bioreactors need relatively consistent tile flow to maintain saturated conditions for the naturally occurring microorganisms to complete the denitrification process. Bioreactors cannot be placed in areas where surface flows may cause ponding of water on top of the bioreactor. It is important to keep the bioreactor footprint out of highly trafficked areas to prevent the compaction of woodchips within the trench. The presence of surface intakes requires additional consideration to prevent sediment accumulation in the bioreactor.

The decision tree below can help guide you through the process to determine if a bioreactor could work on your farm.

You can learn more about bioreactors and other edge of field practices via print resources, video, webinars and podcasts on our website!

Liz Ripley

Bioreactors, Birds and Butterflies – Oh My!


On Thursday Rob Stout hosted a bioreactor and monarch field day at his farm near Washington, IA. After dinner, attendees got a chance to check out Iowa Learning Farms’ Conservation Station “On the Edge” trailer to see how saturated buffers and bioreactors look and work underground. After the trailer demonstration we all headed out to Stout’s bioreactor.


Rob Stout addresses field day attendees at his bioreactor site

Stout had his bioreactor installed in 2014 thanks to cost share funds available through the West Fork Crooked Creek Water Quality and Soil Health Initiative. The bioreactor is 100′ x 30′ with an 8″ tile and drains about 68 acres. Water quality monitoring done at the inlet and outlet of the bioreactor over the last 5 years has shown that the bioreactor has been effective at reducing the nitrate load. Average nitrate removal has been around 90% for August – October, with slightly lower amounts removed (~43 – 83%) in April – July. Check out the installation video here to see how the bioreactor was built! Stout explained that the monitoring has also shown a decrease in the nitrate loads at the inlet of the bioreactor over the 5 years it’s been installed, due to changes he’s made in his nitrogen management (splitting up applications) and likely also related to his use of cover crops.


Attendees also heard from Taylor Shirley, an Iowa State University Graduate Research Assistant in the department of Natural Resources Ecology and Management. Shirley is working on a research project in the Washington area related to pheasants, quail and their habitat. She described the methods used for tracking and monitoring the birds, as well as biomass measurements and vegetation surveys to analyze how the birds are using cover crops and if they are using them for nesting. One unique finding that Shirley mentioned was an Upland Sandpiper nest found in cover crops when they were conducting nest searching.


The evening wrapped up with Holly Shutt, from Pheasants Forever, discussing monarch butterflies and monarch habitat. She explained the monarch lifecycle and the importance of milkweed being available for monarchs since it provides the only food that they can eat during their caterpillar stage. After seeing the lowest recorded monarch populations around 2012-2013, a lot of work has been done to educate the public about the importance of monarch habitat – not just milkweed, but also other flowering plants that they can get nectar from. Although there has been progress made, there is still a lot of work to be done! Stout’s bioreactor area is planted with a pollinator habitat seed mix and Shutt explained some of the basics of seeding and management for those interested in establishing their own pollinator habitat.

If you’re interested in attending an Iowa Learning Farms field day, check out our events page to see if there will be one in your area!

Hilary Pierce

Conservation Practice Showcase Showdown

Who would have thought that the best time of year to catch a field day would be in the beginning of August? The temperature when we started was in the low 80’s and by the time we finished it was in the mid 60’s. No bugs, no humidity… perfect. The turnout was also fantastic with over 60 in attendance.

DSC_2170The event was held at the Iowa State University Uthe Farm near Madrid, in partnership with Iowa State University Extension and Outreach, and Iowa State University Research and Demonstration Farms. Attendees had the opportunity to tour four conservation practices installed at the farm.

Saturated Buffers

Tom Isenhart, ISU Natural Resource Ecology and Management Professor kicked things off. He spoke about the origins of the saturated buffer practice and how incredibly effective they are at removing nitrates from the water.

“We raise the water table so that the water soaks into the black soil, where all the microbes are. We are sending water into the stream that is much cleaner than when we received it.” ~Tom Isenhart

An attendee asks, “Is that why they are called saturated buffers?” Tom replies, “Exactly!”


Michelle Soupir, ISU Agricultural and Biosystems Engineering Associate Professor, and Natasha Hoover, ISU Agricultural and Biosystems Engineering Research Associate, led the discussion on bioreactors. They talked about installation, costs and how they are experimenting with corn cob bioreactors.

“We have some pilot scale bioreactors that have been replaced with corn cobs. We know they work better, but there are still design questions about how long they last.” ~Michelle Soupir

They took a sample and used a nitrate test strip at the inlet and outlet of the bioreactor to see how effective it was at removing nitrate from the water. The results were quick – 25ppm at the inlet and 0ppm at the outlet.


Adam Janke, ISU Natural Resource Ecology and Management Assistant Professor and Extension Wildlife Specialist, and Sean McCoy, Iowa Department of Agriculture and Land Stewardship Environmental Specialist, talked about how important oxbows are to water quality as well as habitat.

“Oxbows are an attempt to slow the water down to allow denitrification to take place. However, there is a secondary benefit to oxbows and that is the aesthetics and the wildlife.” ~Adam Janke

When asked what his dream species would be in the oxbow, Janke replied that it would probably be the Topeka Shiner.

Pollinator Habitat

As the sun began to set, Seth Appelgate with ISU Monarch Research Team, spoke to the importance of reestablishing pollinator habitat. He suggested that there were many areas that people mow that could be converted with minimal cost.

“Pollinator habitat is actually cheaper over the long run because you save time and money mowing it. It’s more attractive, covers a larger area and has diverse stands that help with water infiltration. Plus, monarchs need these areas.” ~Seth Appelgate

If you’re interested in learning more about bioreactors, saturated buffers or other conservation practices, check out our upcoming field days to see if there will be one near you!

Nathan Stevenson

A Beautiful Evening for Bioreactors

The rain stayed to our south and we ended up having a perfect evening to see Bob Floss’s bioreactors on Wednesday, July 31. Over 50 people joined Iowa Learning Farms, Iowa Corn and Iowa State Extension & Outreach to learn more about how bioreactors work, the installation process, and get a chance to chat with farmer Bob Floss and contractor Chris Herbold.

DSC_2101After enjoying dinner, attendees got a chance to learn about the basics of saturated buffers and bioreactors while viewing the models in the Conservation Station “On the Edge” trailer. These models help to show how these practices work and what’s going on under the ground surface because once a saturated buffer or bioreactor has been installed, you can only see the control structures for them. Field day participants were very interested in learning more about these practices and asked us some great questions. To learn more about these practices, check out these saturated buffer and bioreactor infographics from Iowa State Extension & Outreach.


DSC_2118Chris Herbold, the contractor who installed the bioreactors in the spring of 2018, was also on hand to answer specific questions about installation process. He explained that it took them about three days to do the first bioreactor, the first one he had installed, but that they learned throughout the process and were able to install the second bioreactor in about a day and a half. Herbold joked that he and his crew will be very busy for years to come, and may be able to get their installation time down even further, due to the large number of bioreactors that are needed to meet Iowa’s Nutrient Reduction Strategy goals.


Attendees were curious about how the stop logs in the control structure worked and how often Floss and Herbold had to go out to check the bioreactors. They explained that they were checking and adjusting the water level about once a week during spring snow melt, but need to do so less frequently now. They were also excited to share that they have been using nitrate test strips and have been seeing impressive nitrate reductions from the inlet to the outlet of the bioreactor, when they remember their glasses, that is!

If you’re interested in learning more about bioreactors or other conservation practices, check out our upcoming field days to see if there will be one near you!

Hilary Pierce

Discovering My Passion

ILFHeader(15-year)IMG_4905This is my second summer working with Water Rocks! and Iowa Learning Farms, my first being the summer of 2017. There have been a few moments throughout this summer that made me realize how much I have changed since I first began my internship here two years ago.

Back when I started, I had just changed majors to become a biosystems engineering major, and I was set that I was going to do the bioprocessing/biofuels track. Through my experience with the water resources internship, I found what I really wanted to do, which was working with water quality and other environmental issues.

When I first began the internship, I knew nothing about agriculture, water quality issues, or anything about what I wanted to do in the future. Now, besides the knowledge and experience I have gained through my education and my internships, I also have some solid ideas about what I want to do.

I realized this very recently through two very different workdays.

The first was field work we did for the monarch butterfly survey. We had to trudge through thick, soggy grass taller than me and fight off mosquitos and ticks while looking for milkweed plants in CRP fields. It was miserable, annoying, and painful, but also somehow fun! It was cool to learn how to identify the different species of milkweed, and it was a great feeling when you finally found a plant while walking in circles in chest tall grass for what seemed like hours (even though it was probably 5 minutes).

Monarch MonitoringIt was simultaneously one of the most fun and most miserable days of the summer. And with the help of an entire can of bugs pray, I’m still here! If you had asked me at the beginning of the summer 2 years ago to do that, I’m not sure what I would have done. I do know that I would have had a much worse attitude about it, and that I would not have had any fun whatsoever. I think that represents one way that I have grown, which is to be better at taking things as they come and dealing with it. I think is a very valuable attitude to have in the environmental field, because nothing ever goes as planned when it comes to nature.

The other day was one where I had to present the Conservation Station On the Edge trailer at a field day in NW Iowa. I had been on field days like this before, but with a staff member, and so I had heard this being presented but had never done it myself. I was nervous about doing this myself, because I was worried that I would get questions I couldn’t handle or forget to mention something important. I knew that I had learned a lot of this stuff through coursework and the internship, but I somehow felt that I still wasn’t prepared. But everything went well. I presented the models and information for both the saturated buffer and woodchip bioreactor, and it seemed like I was keeping the audience’s attention.

When it got to time to ask questions, I was nervous, but as they came, I found myself naturally answering them. It turns out, shockingly, that I learned something in college. I think that a major reason that I was nervous for grad school was that somehow, I felt that I wasn’t ready, and that I had managed to fake my way through college. That presentation was one of the first times that I felt confident in what I had learned and my ability to explain it to someone effectively. This has given me a lot of confidence for the future. Going from not knowing a thing about this field two years ago all the way to explaining edge of field practices to landowners is quite a jump, and something that I’m proud of.

Water Rocks! and ILF have really shaped my educational career, and it is an experience that I will take with me and remember for a long time.

Andrew Hillman is participating in the 2019 Water Resources Internship Program at Iowa State University.  Hillman grew up in Bettendorf and graduated from Iowa State University with a degree in Biosystems Engineering. He is off to North Carolina State University to pursue a graduate degree in the fall.

Bioreactor Installation a Success


The rain didn’t dampen the excitement of a new bioreactor being installed near Albert City last night. Olie and Lois Leimer were pleased to share their newest conservation practice on their farm with fellow farmers, landowners and contractors at our field day.


Lois and Olie Leimer discussing their new bioreactor being installed behind them with Lee Gravel, Headwaters of the North Raccoon Watershed Coordinator.

The Leimers are long time implementers of conservation practices. They began using no-till many years ago in an effort to save on fuel and time. They have also added cover crops to their farm to reduce soil erosion and improve soil health and water quality.

“It’s a work in progress. We’re always looking for ways to improve our farm and our impact on water quality,” state Olie.


Field day attendees were able to check out the bioreactor site and hear from Brian Heinsohn, owner of Heinsohn Digging & Tiling, who led the contractor installation team.

Leimer approached the local Natural Resources Conservation Service about two years ago to begin the process of installing the bioreactor.  Together with Lee Gravel, Headwaters of the North Raccoon Watershed Coordinator, and ISG in Storm Lake to design and construct the bioreactor, the finished edge of field practice will treat about 80 acres of drained row crop acres.


Nearly completed bioreactor.

The actual installation process goes fairly quickly. The trench and control structures were installed on Monday and by Tuesday afternoon the woodchips were delivered. They would have finished on Tuesday, but the area was left open so attendees could view the trench and woodchips. In total there is about 3.5 feet of woodchips that will be covered by about one foot of soil. Once the soil is in place, a pollinator habitat mix will be seeded over the bioreactor.

The bioreactor will be monitored for how nitrate removal throughout the upcoming years as partners work to meet the goals of the Iowa Nutrient reduction strategy. If you are interested in installing a bioreactor on your farm you can contact Iowa Learning Farms or your local NRCS office.

Be sure to check out upcoming field days in your area by visit our events page!

Liz Juchems

Attend an Upcoming Field Day Near You!

ILFHeader(15-year)Mark your calendars and be sure to submit your RSVP for a field day near you this summer. We will be hosting more in July, August, and September – so stay tuned for more information later this summer.

June 11, Bioreactor Field Day
Hosted by Olie Leimer
1598 Highway 3
Albert City, IA
Buena Vista County
Partners: Land Improvement Contractors Association, Iowa Agriculture Water Alliance, Natural Resources Conservation Service, Iowa Department of Agriculture and Land Stewardship, and Iowa Corn
Press Release

June 13, Native Perennial Planting Workshop
Smeltzer Farm
2610 Nelson Ave
Otho, IA
Webster County
Partner: Iowa State University Extension and Outreach
Press Release

June 18, Native Perennial Planting Workshop
Spirit Lake Community Center
1602 15th St
Spirit Lake, IA
Dickinson County
Partner: Iowa State University Extension and Outreach
Press Release

July 9, Native Perennial Planting Workshop
Whiterock Conservancy Burr Oak Visitor’s Center
1436 IA-141
Coon Rapids, IA
Guthrie County
Partner: Iowa State University Extension and Outreach


Are you interested in hosting a field day? Contact Liz Juchems, or 515-294-5429 to get the planning started!


A Huge Thank You!

ILFHeaderOn behalf of the Iowa Learning Farms team, I would like to thank all of our hosts, speakers and partners for an awesome 2018 Field Day season. This year our 24 field days and workshops were attended by 1,134 farmers, landowners, government employees, students and educators, media and agribusiness staff. The topics covered included: cover crops, grazing cover crops, soil health, strip-till/no-till, bioreactors and other edge of field practices, water quality, Emerging Farmers and events for women landowners.  Implementing these practices on our landscape is so important in helping us reach our Iowa Nutrient Reduction Strategy goals.

Keep an eye out for mail from us this January! We will be mailing a brief survey to all farmers/operators and landowners who attended an ILF-sponsored field day or workshop.

Be sure to check out our events page on our website to attend a 2019 event near you.

Hilary Pierce