The Practical Blog

Practical Farmers' blog is a place where staff share news, updates, photos, reflections and other musings on our work and members in a more informal setting.

Dave and Meg Schmidt operate a diverse livestock farm, Troublesome Creek Cattle Co., in Exira IA; raising grass-fed and finished cattle and sheep, pigs and poultry. Feeding the 100% grass-fed cattle herd over the winter is a great expense, so they have experimented with feeding different forage sources- hay, cover crops, crop residue and stockpiled pasture to minimize costs. Hay is the most expensive forage to feed during the winter, so the Schmidt’s were curious how the could extend their grazing season and decrease the amount of hay they have to feed.

The full Practical Farmers’ Research Report is now available.

Sylvie Schmidt checking on cattle as they graze stockpiled perennial pasture.


This research was conducted during the non-growing, winter seasons, from 2013 to 2017. The Schmidts recorded the movement of animals through different lots and pastures, tracked weights on a monthly basis, and noted the amount and value of feed consumed.  Monitoring began when animals finished the normal summer grazing and moved to winter crop fields or stockpiled pastures – approximately November through the end of April.

Cover crop grazing

Cereal rye, wheat, hairy vetch and/or oats were planted three out of the four years, for the purpose of grazing during the winter. Table 1 shows seeding records and costs. In 2013-2014 and 2014-2015, cover crops were aerially seeded by a neighbor. In 2016-2017, cover crops were drilled by Dave.

table 1

Stockpile grazing

Stockpiled forage in the pastures was comprised of orchardgrass, red clover, smooth brome grass, tall fescue and Kentucky bluegrass. Generally, the Schmidts stopped grazing pastures in August in order to grow enough to stockpile for winter.


The percentage of hay consumed by the cattle herd during each non-growing season is shown in Figure 1. The remainder of the herd’s ration was fulfilled by a mix of cover crops, crop residue and stockpiled pasture, depending on the year. Herd size is listed in animal units (AU) which equate to 1,000 pounds of animal.

Figure 1

During the winters of 2013-2014 and 2014-2015, cover crops and crop residue provided almost half of the winter feed needs for the herd. During the winter of 2015-2016, the most hay was fed, because the farmers were not able to plant cover crops the season prior. The least hay was fed in 2016-2017, due to a combination of grazing stockpiled pastures along with cover crops and crop residue.

Growing animals were weighed approximately once a month. The weights nearest the beginning and end of the winter feeding period were used to figure average weights and average daily gains (ADG). “Last year [2016-2017] was our first time with significant stockpile grazing and the finishers are the heaviest we’ve ever had them at this point in time. We were able to dramatically reduce the amount of time the cattle were fed hay in the lot – roughly early February to mid April. Perennial stockpile really pays because we can graze it shorter to the ground when it’s dormant, so animal days per acre go way up” stated Dave.

Figure 5

Utilizing diverse winter forage sources allowed the Schmidts to feed less hay, increase the size of their herd and save money.  The Schmidts concluded that incorporation of stockpiled pasture is necessary to decrease costs and work towards their goal of only feeding hay for one month per year. To see a detailed cost comparison and to read more about calf and feeder weight gains over each winter, read the full report here.

“We should be able to graze stockpiled annual and perennial pasture well into December. When that feed source is gone we will feed baleage; wrapped oats that were cut at flowering and wrapped alfalfa and orchardgrass. Once that’s gone we’ll have to buy dry hay.”  Dave and Meg hope these research results aid other farmers when deciding how to extend their grazing season and cut winter feed costs.

Kathy Voth

Kathy Voth is one of the featured speakers at Practical Farmers of Iowa’s 2018 annual conference (Jan. 18-20, in Ames), and we’re excited she’s able to join us. Kathy publishes the popular weekly online grazing magazine, “On Pasture,” in partnership with Rachel Gilker.

For 12 years, Kathy also worked with the Bureau of Land Management, working with ranchers, university researchers and agency staff to develop solutions that help communities live sustainably in their environment. In 2004, she developed a method, based on principles of animal behavior, for teaching cows to eat weeds.

I chatted with Kathy to learn a little more about why she advocates that farmers reconsider the place of weeds in their pastures. It turns out that weeds are highly nutritious for cattle, in addition to their abundance and resiliency to weather — and that cattle, just like people, learn to eat the food they grew up seeing their mothers and elders consume.

Kathy will lead a workshop on this topic, “Teaching Cattle to Eat Weeds,” at our annual conference next month. Visit to learn more or register.

Here’s what Kathy had to say to some of my questions.

When you first developed the concept of teaching cows to eat weeds, around 2004, it was a pretty radical idea for graziers. Have you seen more buy-in to this idea over the past 13 years?

That’s not changed – it’s still a pretty radical idea. Most people think that cows eat grass, sheep eat forbs and goats browse brush. What it comes down to is animals eat what they’ve learned to eat. Our thoughts about what animals eat really restricts us and them.

It kind of goes in waves. For a while I worked really hard at getting the information out. One time, I went to Missouri and when I came back, told my dad how people had pretty much laughed at me. Then five years later, they invited me back to the same conference to talk about the same thing.

My dad said I probably shouldn’t go. Well, I went and they thought I was the greatest thing. It depends on what people are ready to think about and accept, and you just have to be there at the right time.

What do you consider a pasture weed?

Lots of people are really hung up on the idea that a weed is bad and should be killed, but a weed is just a plant out of place. I think weeds are an all-around good thing.

Even among domesticated cows, different groups eat different things. I was in Boulder County, Colorado working with a group of cows, and they were pretty much eating anything. I thought, ‘I’m going to take in every single plant they’re eating and test it.’ It was like 20 plants. One was field bindweed. They’d been eating that long before I showed up.

A lady at the testing facility said she’d really like her cows to eat field bindweed – her cows didn’t have this particular culture. There are examples of cows eating all kinds of things.

From my perspective, we have wasted way too much time and money managing weeds and should let our cows eat them. The beauty of the process is that you train one group of animals to eat one weed and watch them in pasture. They will generally try other new plants on their own, because the training process opens their eyes to the possibility that other things can be food.

Mostly, we try to manage for grass.

Why do you think that is? If cows have these potentially diverse food cultures, why do you think there’s this misconception about and focus on grass?

My theory is the reason we think cows’ [only natural diet is] grass is that, when we could start to harvest forages and store them for long-term, about the time we got mechanized enough to do that, grass was an easy thing to store. So that’s what we fed them – the more grass you have, the more you have to store.

Back in the 1750s to about 1850, people thought cows ate carrots, beans, potatoes and turnips – things we’d never think of feeding them. That just pointed out to me that cows are flexible. It’s people who are inflexible.

Have you ever heard back from anyone who was initially skeptical of teaching cows to eat weeds, but had a change of heart?

I’ve had lots of people that were really skeptical and went ahead and did it – like one guy in Montana. I think he got roped into the project by a gal he worked with at [a natural resources conservation office]. I sent him instructions, he started training and I came out to help. Sure enough, [the cows] started eating some weeds, then other weeds.

The heifers we had trained he had in a pasture divided in half with a single wire. The steers on the other side of the wire learned how to eat the weeds from the heifers – so he was very sold on it.

The guys I worked with in Bolder County, Colorado were like, fine, we’ll give you some cows to work with but we don’t want to be involved. I would do different projects with these cows, trying them on different weeds. Eventually their owners became my friends. The last year I worked with them, they had a herd of 800 cows.

I didn’t always get the same cows, and the ones I trained that went out with the herd taught others. It took about six years of sorting cows – but now they run for the weeds first.

What that guy was really impressed by was that some of the native plants were making a comeback.

If graziers already feel they’re doing a good job managing their pastures, is there still a reason they should consider training their cows to eat weeds?

If you know what you’ve got in your pasture and know what you’re managing for, you can do a good job and maybe you won’t have any issues.

The problem comes when something bad happens – it gets dry, you’re managing as best you can but you overgraze. These accidents happen often, because weather changes often. Suddenly you have more cows than you thought.

My thought with [developing this approach] was that if my cows know how to eat weeds, I don’t have to worry because weeds are very resilient. They come up during drought, so my cows will always have something to eat.

Grazing weeds is a strategy for resilience. Plus – nobody knows this – weeds are more nutritious than grass. They are basically the equivalent of alfalfa or better.

Protein is one of the limiting factors for most cattle; it’s a hard thing for most cattle to get. Weeds are very high in protein, and very digestible. That means cows can gain weight even if their pastures are lower quality.

Any time an animal has protein and dry grass, they can eat all that dry grass as well and still get an adequate diet. The protein helps them process dry food better.

You might even be able to raise more cows – you basically have 43 percent more forage if you teach your cows to eat weeds.

Does your method for teaching cows to eat weeds work just as well with older animals? For graziers who want to start doing this, would they need to plan for a longer training period?

I started with heifers because we all believe younger animals learn more quickly than older ones. But then I started training anything that anyone brought me and it always worked.

Some individuals are better weed-eaters than others, but it wasn’t breed-specific, it wasn’t age-specific. If a mother cow was a really experimental eater and would eat a lot of new things, her calves were also like that – because I got to follow some of the calves over a number of years and watch their offspring.

The bulls were really interesting, because I would teach the heifers and they would put the bull in for just a day, and he would learn really fast – I think because he was trying to impress [the cows] and fit in.

The cows have taught me a lot over the years.

How do cows compare with goats when it comes to tackling pasture weeds? For graziers who do mixed-species grazing and already integrate sheep or goats, is there still a reason for them to consider training their cows too?

Goats don’t do a better job. I did goats for a long time and did prescribed grazing with them. What I found is cows are every bit as good as goats.

The reason I would always choose cows over goats is cows are so much easier to manage and sell on a market than a goat is. It depends on where you are – I think the goat market is getting better. But building fence for goats is so hard; they’re just so smart. But a cow, I can build a one- or two-strand fence and they’ll stay in.

I tell people if you already have cows and just want to get goats to manage weeds, don’t do it. Cows can do every bit as good as goats – even on brush.

But if you think you have a market for the goat or just happen to like goats and sheep, then that’s fine. I would probably still teach the cows to eat weeds.

First I would watch what everybody is eating, because before I knew cows could eat weeds, I knew there was research showing that you could put five goats per pasture and everyone would eat well. But I’ve since found it’s maybe 2.5 goats or 3 sheep per pasture.

Once cows have been trained to eat weeds, how much active pasture management is needed? Do you still have to get rid of noxious weeds?

For example, in Montana, they have a lot of spotted knapweed and really need to reduce that. To do that, there are times you really should put your animals in a pasture. I would do that in mid-July for Montana, because at that time your other plants have senesced. You’ll have grazed your spotted knapweed before it goes to seed, even if it flowers after that, research has shown that most of the seed isn’t viable.

You could manage timing that way.

One of the reasons I really thought training cows to eat weeds would be a good thing is because, while you can put up multiple fences and force cows to eat everything, in some places that’s not viable – the landscape is too big, or water sources aren’t close enough together. My thought is a if cow is out there 24/7 and knows to eat weeds, you don’t have to do anything about it.


After completing two years of cucumber enterprise budgets, Ann Franzenburg and Emma Johnson looked at their farms and decided: “Let’s do cherry tomatoes.” For this enterprise budget, both farmers did a careful accounting of the revenue, costs, and labor for their 2017 cherry tomato crops. The analysis of their data, and their comments on varieties, harvesting, and marketing, is available in a new Practical Farmers’ Research Report: Enterprise Budget for Cherry Tomatoes.

Johnson cherry tomato

Key Findings

  • Both farms had profitable cherry tomato crops, netting $1.31/lb at Franzenburg and $1.54/lb at Johnson
cherry tomato fig 1

  • Labor was the largest expense for both Franzenburg and Johnson, accounting for 62% and 68% of their total expenses, respectively.
  • Harvesting and packing was the most time-consuming task on both farms, accounting for 74% of labor-hours at Franzenburg and 62% of labor-hours at Johnson.
cherry tomato fig 4


Franzenburg and Johnson both plan to repeat the cherry tomato enterprise budget for 2018 to provide a two-year look at the crop’s production and profitability.

Click here, or on the image below to download the full report.

cherry tomato cover



Carmen Black and Mark Quee raise sheep on their diversified vegetable farms. They were curious if grazing a cover crop prior to a fall crop, rather than simply terminating the cover crop by mowing and tillage, would have an impact on the yield of the next crop. For this trial each farmer measured the yield of a fall brassica crop following grazed and un-grazed cover crops. Said Black, “I’m interested in finding ways to incorporate my sheep into my vegetable operation more holistically, but also in compliance with food safety regulations. This trial will allow me to see if there’s any measurable difference right away.”

The full Practical Farmers’ Research Report is now available.


Farmers set up plots in a randomized, replicated pattern. During the spring, a cover crop of oats and peas was seeded to all plots. Farmers used moveable electric fence to exclude the sheep from control (cover-only) plots, while the treatment plots were grazed. Quee grazed sheep in the plots on May 30; Black grazed sheep in her plots on June 5. Biomass samples were taken from all plots by clipping aboveground foliage at ground-level (four 1-ft2 quadrats per plot), air-dried and weighed at the Practical Farmers of Iowa office. Biomass results are reported on a dry matter (DM) basis. Production practices, grazing, planting and harvest information for each farm is available in Table 1.

grazing table 1

After termination of the spring cover crop by grazing or mowing and tilling, Black and Quee seeded fall brassica crops. The rows ran the length of the plots. Quee measured broccoli (cv. Gypsy) yield; Black measured Brussels sprouts (cv. Diablo) yield. Planting, management and harvest practices were consistent across treated (grazed) and control (un-grazed) plots. For broccoli, Quee counted, weighed and measured the width of heads in each plot. For Brussels sprouts, Black harvested entire stalks, then counted and measured sprouts, and graded sprouts based on USDA criteria for color and firmness, by plot.


Sheep graze the treatment plot at Quee’s.

Quee incorporates the cover crop during the trial.

Quee incorporates the cover crop during the trial.

black brussels

Brussels sprouts being measured at Black’s.


Brussels sprout yield at Black were not statistically different in grazed and un-grazed plots; only color ranking was statistically different, with the grazed plots tending lighter green than un-grazed
plots. Average number of sprouts per plant was 76.6 in the grazed plots, and 64.9 sprouts/plant in the un-grazed plots. Sprouts in grazed plots, on average were slightly larger and more firm than in un-grazed plots, but the means were not statistically different. “Sometimes you imagine you see a difference in the treatment plots,” said Black. “Just looking at the plants I didn’t think there was a difference. And even though the means are not statistically different, 12 sprouts per plant is a big difference. It shows the importance of actually counting,” she said.

grazing fig 4

Quee had nice sized broccoli crowns, though the average weights were not statistically different by treatment. Crowns averaged 1.44 lb/crown and 1.35 lb/crown for the grazed and un-grazed plots, respectively. There was not a statistically significant difference between plant yield (lb/ft2) or crown yield (crown/ft2).

grazing fig 5
Broc harvest 2017

Broccoli harvest at Quee’s.

Black is interested in grazing more spring-seeded cover crops based on trial results; Quee plans to stay with his current system of grazing in fallow years and in the early spring and late fall.

Click here or on the image below to view the .pdf of the full research report.

grazing cover

As farmers wrap up their season and plan for next, PFI’s farmer-cooperators have an additional responsibility: submit the data they collected from this year’s research trials and plan next year’s projects.

The first week in December marks the annual two-day Cooperators’ Meeting where farmer members meet to discuss these research results with each other and plan on-farm projects for the following year. In preparation for this meeting, staff members in Practical Farmers office are busy collecting this data, analyzing it and publishing the findings in detailed research reports for sharing far and wide.

In 2017, 51 farmer-cooperators participated in 71 projects that concluded or are still on-going.

2017 On-Farm Research Project Locations:

2017 Cooperators Program Map

Since 1987, more than 230 different farmers have conducted 1,359 research trials on their farms. Results from this research are shared through research reports; the Practical Farmer, our quarterly newsletter; in various agriculture magazines, at field days and workshops; at our annual conference; and at our annual cooperators’ meeting. Knowledge from these research projects has influenced both farmers and university researchers to adjust their designs to better fit farmers’ needs – and even been the foundation for ground-truthing hypotheses that ultimately led to university research projects.

2017 Field Crops Projects

  • Winter Cereal Rye Cover Crop Effect on Cash Crop Yields, Year 9 Update

    Chris Teachout

    Chris Teachout

  • Hybrid Rye Variety Trial
  • Tea Bag Soil Decomposition Index: Cover vs. No-cover
  • Interseeding Covers into Seed Corn at V3-6 stage
  • Corn Leaf Orientation for Interseeding Covers at V5
  • N Fertilizer Strategies for Corn Following Cover Crop
  • Rolling Cover Crops and Soybean Row-Width
  • Soybean Row-Width and Rolled Cover Crop Mulch
  • Roll-Crimping Cover Crops and Soybean Planting Date
  • Spring-seeded Brassica Cover Crops
  • Spring-Seeded Oat Cover Crop
  • Spring-Seeded Cover Crop Mixes
  • Underseeded vs. Mid-summer-seeded Green Manures for Corn
  • Planter Settings for Organic Corn

2017 Livestock Projects

  • Grazing Cover Crops
  • Beef Carcass Quality
  • Pelleted Small Grains
  • Feeding Hybrid Rye
  • Apple Cider Vinegar and Dairy Cattle
  • Bird Monitoring in Rotationally Grazed Pastures
  • Forage-Fed Pigs
  • Winter Feed Monitoring on a Grass-Fed Cattle Farm

2017 Horticulture Projects

Carmen Black and the Sundog farm crew

Carmen Black and the Sundog farm crew

  • High Tunnel Tomato Variety Trial
  • Long Purple Carrots
  • Summer Lettuce Variety Trial
  • Cherry/Salad Tomato Enterprise Budgets
  • Sheep Grazing Cover Crop Before Fall Brassica
  • Mulch Trial in Strawberries
  • Annual Flower Mix Strips
  • Summer Broccoli Variety Trial, 2013-2017



Click here to learn more about the Cooperators’ Program

A roller-crimper presents farmers the opportunity to mechanically terminate cover crops without chemicals or tillage. This method is dependent on a large amount of cover crop growth and the cover crop reaching the flowering stage before crimping. A roller-crimper is a large, metal cylinder with “chevron” pattern blades that simultaneously lays the cover crop flat on the ground and crushes the stem in several places. Successful termination of a cover crop with the roller-crimper is dependent on the cover crop being at the anthesis (flowering) stage at the time of rolling. For cereal rye, this flowering stage is likely to occur in late May in Iowa.

Farmer-cooperator Tim Sieren compared soybean seeding dates relative to cover crop termination (before and after) as well as cover crop termination techniques (chemical vs. roll-crimp). “If I can manage a roller-crimper system in soybeans, while maintaining yields,” Sieren said, “I could drastically reduce herbicide use.”

Read the full report here: Roll-Crimping Cover Crops and Soybean Seeding Date.

Rolling covers and soy seeding date cover

How was the trial conducted?

This trial was conducted by Tim Sieren of Green Iron Farm near Keota in Washington County. Treatments included:

  • Plant-then-spray: plant soybeans (Apr. 24), then spray the cover crop (May 5)
  • Spray-then-plant: spray the cover crop (May 5), then plant soybeans (May 7)
  • Plant-then-roll: plant soybeans (May 7), then roll the cover crop (May 30)
  • Roll-then-plant: roll the cover crop (May 30), then plant soybeans (May 30).

Fellow PFI member Levi Lyle roll-crimping a cereal rye cover crop.

Fellow PFI member Levi Lyle roll-crimping a cereal rye cover crop.


Soybean yields were mostly affected by cover crop termination date (table below). Regardless of soybean seeding date, yields were greater on average by 10.5 bu/ac when the cover crop was terminated with herbicide on May 5 compared to roll-crimping the cover crop on May 30.

Cover crop biomass at the time of termination and soybean yields at Tim Sieren's in 2017.

Cover crop biomass at the time of termination and soybean yields at Tim Sieren’s in 2017.

Roll-crimping the cereal rye cover crop proved to be a challenge. “The rye needs to be roll-crimped before the planter goes through, not after,” Sieren said. “I didn’t have a heavy enough stand to crimp down, and stay down (possibly due to the May 17 hailstorm). It didn’t kill all the rye, and after 2 weeks, you couldn’t tell it had been crimped, and it stayed greenish until I finally hit it with glyphosate 2 weeks later. Then it died and the beans finally acted like they wanted to grow.”

When Sieren waited to roll-crimp the cover crop on May 30, soybean yields were similar between the May 7 and May 30 seeding dates, but they were also less than when the cover crop was chemically terminated on May 5. With the May 30 cover crop termination (roll-crimp), Sieren achieved yields equivalent to his county’s average with only a single in-season herbicide application on June 27.

For more details on this trial, read the full report: Roll-Crimping Cover Crops and Soybean Seeding Date. This project was supported by the Iowa Department of Agriculture and Land Stewardship, Division of Soil Conservation.

For more information about this study and other studies as part of PFI’s Cooperators’ Program, contact Stefan Gailans at [email protected]


Another successful field day season is behind us. Many staff will tell you that field day season is the most exhausting and fulfilling part of the year!  With good reason. Practical Farmers of Iowa coordinated 26 field days in 2017. Our field days brought together 1,418 attendees and covered a diverse range of topics from organic crop rotations to dried flower production to farming potholes and just about everything in between. We are so thankful to our field day hosts who shared both their farms and their experience.

As we look back at our field day statistics, many things stand out. But one in particular shows we are on a good path.  In 2017, 44% of our attendees came to a field day for the first time. This is a great indicator that we continue to provide relevant topics and our message is spreading. Thanks to all you first-timers out there! We are looking forward to seeing you next field day season.

At Practical Farmers of Iowa, we are fortunate to have a passionate group of over 3,000 members. While our members identify field days as one of their favorite types of events, we are also drawing in a much larger crowd. In 2017, 52% of our field day attendees were non-members and they identified “word of mouth” as the primary source for hearing about field days. We are thankful our mission to strengthen farms and communities is reaching well beyond our membership and thankful to our members who are inviting others to join the conversation. Please consider inviting a neighbor or friend to the next PFI event you are attending.  “Welcoming everyone” is not just a value we list on paper, but live out on a daily basis as we work to create viable farms now and for future generations.

We also encourage the learning and sharing to continue beyond our events and we are excited to report that 99.5% of you reported that you intend to share what you have learned at PFI field days with others. That is fantastic! We know that the quality of our programming coupled with the passion of our field day attendees is a way to create change. Here are a few results highlighting the quality and effectiveness of our field day programming in 2017:
















Sharing knowledge is important, but we want to see that knowledge lead to change. To evaluate this, we ask attendees to respond to their intent to change and actual changes made to their farming systems. Here are the results:

intent to change

We are so thankful to our field days hosts for sharing their experiences and their farms. Our hosts for 2017 were: Jill Beebout, Matt Schuiteman, Fred Abels, T.D. Holub and Sarah Gericke, the Henry family, Maggie McQuown and Steve Turman, Phil Specht and Mary Damm, Jon Yagla and Wren Almitra, Deb and Eric Finch, Craig Fleishman, the Frantzen family, the Ausborn family, Marty and Mary Schnicker, Dave Brandt, Wendy Johnson and Johnny Rafkin, Tyson Allchin, Jan Libbey, Kevin and Ranae Dietzel, Cheryl and Mike Hopkins, Russ Wischover, Chris and Janenne Teachout, Jerry Peckumn, the Canfield family, the Rosmann family, Darla and Michael Eeten, Jamie Hostetler, Fred Howell, Jayme Fowler, and Jason Grimm. We could not have farmer-led events without you.

In addition to our summer schedule, 235 of you attended  6 spring field days in March and April highlighting cover crops. A big “thank you” to the following hosts: Wade Dooley, Jack Boyer, Bruce Carney, Russ Brandes, Ward Van Dyke, and Mark Schleisman. Keep your eyes open for announcements on our 2018 Spring Field Day series.

If you missed the action “live”, you can still get important information through our field day recap blogs and On-Farm podcast episodes:

Following our Practical Farmers of Iowa Annual Conference in January, our staff will begin the work of coordinating another successful field day season. Until then, I will leave you with a few quotes from this year’s attendees to keep you motivated until next season.

” Good diversity of topics!”

“Awesome to be out in the field, pulling up soil and doing hands on stuff.”

“Your event showcases best and most intelligent thinking I have seen! A wonderful field day. Lunch was good too!”

“So much good information, I was inspired and am looking forward to applying our information!”

“Thank you. Just wanted to come see things and keep the future vision alive.”

“It is good to see practiced applications of ideas.”

“I think honest presentation of obstacles is very valuable.”

Thanks again, and see you next year!



Field Day Re-Cap: Dried Flower Production with Fred Howell


How does a cover crop affect corn and soybean yields? Winter Cereal Rye Cover Crop Effect on Cash Crop Yield: Year 9 is now available! This is a long-term project being conducted by Iowa Learning Farms and Practical Farmers of Iowa. Between 2009 and 2017, 12 farmer-cooperators have contributed to 63 site-years of on-farm research to investigate what effect a cereal rye cover crop might have to yields of corn and soybeans.

A no-cover (left) and cover (right) strip at Kelly Tobin's on Apr. 20, 2017.

A no-cover (left) and cover (right) strip at Kelly Tobin’s near New Market on Apr. 20, 2017.

Over the course of this project, farmers reported that in 59 of 63 site-years, properly managed cover crops had no negative effect on corn and soybean yields. Of those 59 site-years, soybean yields were improved by cover crops in 8 instances and corn yields were improved in 2 instances (both occurring in 2016).

How the Study was Conducted

This long-term study employs a “paired strips” design. Cooperators established and maintained replicated strips of “cover” and “no cover” that run the length of their field for the duration of the study in corn-soybean rotations. Cooperators were allowed to manage their cover crops and cash crops however they saw fit. The table below shows how the five farmer-cooperators who participated in 2017 managed cover crops and cash crops during the growing season.

crop management 2017

Corn and Soybean Yields 2015 – 2017

In the past three years, corn yields at locations have mostly been at or above 200 bu/ac (Fig. 1). In 2016, corn yields were improved by the cover crop at West Chester and New Market. At New Market, an especially wet year reduced corn yields overall but the cover crop appeared to soften that blow.

CC cover corn 15-17

Figure 1. Corn yields at locations, 2015-2017.

Soybean yields have been near 60 bu/ac the past three years with improvements from the cover crop being observed at New Market, West Chester and Kalona in 2015 and New Market again in 2017 (Fig. 2).

CC cover soybeans 15-17

Figure 2. Soybean yields at locations, 2015-2017.

Long-Term Trends

Over the course of this project, 35 site-years have been dedicated to determining the effect of the cover crop on corn yields and 28 site-years have been dedicated to determining the effect of the cover crop on soybean yields. In the majority of cases, yield were not affected by the cover crop. Read the full report here.

corn and soy trends 2009-2017

For more information on this study, contact Stefan Gailans at [email protected]

This project has been made possible by funds provided by the State Soil Conservation Committee, the Iowa Department of Agriculture and Land Stewardship, NCR-SARE, the Walton Family Foundation and Iowa Learning Farms.



Following a 2016 tomato trial on Rebelski and Mountain Fresh Plus, three farms conducted replicated variety trials in their high tunnels on Big Beef, Rebelski, and Big Dena. Key findings are in the post below, and the full report is available here: Tomato in High Tunnel, Variety Trial.


How was the trial conducted?

Each farmer planted two tomato varieties inside a high tunnel in a randomized, paired trial. Farmer-researchers for this trial were: Tim Landgraf (One Step at a Time Gardens in Kanawha), Lee Matteson and Rose Schick (Lee’s Greens in Nevada), and Mark Quee (Scattergood Farm at Scattergood Friends School in West Branch). Spacing, mulch, trellis style, and planting date were determined by farm, and described in Table 2. Plants for the trial were started indoors and transplanted to the high tunnel (in-ground). Matteson and Schick planted into a heated high tunnel.



Figure 1 shows cumulative yields through the season at each farm. Bold lines represent the varietal average and lighter lines show the individual plot yields. Using repeated measures analysis, average yields for Big Beef were statistically higher during August at Landgraf and Quee, but by the end of the summer, there were no statistical differences in overall yield. At both farms, the earlier-maturing Big Beef showed higher yields early on, with Rebelski catching up toward the end of the season. Statistical analysis was not performed at Matteson/Schick, but total yield for both varieties (Big Beef and Big Dena) at the end of harvest were within two pounds of one another. Similar to the pattern at Landgraf and Quee, Big Beef got off to a faster start, and fruit production from Big Dena eventually caught up in September.

For more details on this trial, read the full report: Tomato in High Tunnel, Variety Trial. This project was supported by the USDA Risk Management Agency and the Ceres Foundation.

For more information about this study and other fruit and vegetable studies as part of PFI’s Cooperators’ Program, contact Liz Kolbe at [email protected]

Successfully raising corn after a cover crop requires timely cover crop termination and N fertilization. Commonly, farmers terminate a cover crop 2-3 weeks prior to planting corn but generally do not need to apply any more N than if they did not use a cover crop. Last year, PFI farmer-cooperator Dick Sloan attempted “planting green”: planting his corn into a cereal rye cover crop that was terminated just two days prior. In Sloan’s case, he saw a 5 bu/ac yield reduction compared to where he terminated the cover crop two weeks prior to planting corn yet stands were equal between the two treatments (Cover Crop Termination Date Ahead of Corn). This past growing season, farmer-cooperators Dick Sloan and Tim Sieren compared terminating their cover crops approx. 3 weeks prior to planting corn with terminating their cover crops within 3 days of planting corn. They also investigated N fertilizer timing and rates across the cover crop termination dates.

You can read the full report of this project here: N Fertilizer Strategies for Corn Following Cover Crop.

N fert strategies 2017 cover shot

How was the trial conducted?

This study was conducted by Dick Sloan in two fields near Rowley in Buchanan County and Tim Sieren in one field near Keota in Washington County.

Cover crops used

  • Sloan, corn following corn field: winter wheat, oats, winter barley and rapeseed
  • Sloan, corn following soybeans field: winter wheat, winter barley and cereal rye
  • Sieren: cereal rye

In addition to comparing cover crop termination dates before corn planting, Sloan compared “low” and “high” N rates in both of his fields (Table 1) while Sieren assessed N application timing and form (applying 140 lb N/ac in each of his treatments) (Table 2).

N fert strategies sloan treatments 2017

N fert strategies sieren treatments 2017


At either farm, when the cover crops were allowed to grow until the May 5 termination (1-3 days before planting corn on either farm), the cover crops produced over twice as much aboveground biomass as the cover crops terminated on Apr. 17 (Figure 1).

Figure 1. Cover crop biomass at the two termination dates at the Sloan (Rowley) and Sieren (Keota) farms in 2017. Apr. 17 termination = 21 DBP at Sloan’s; 19 DBP at Sieren’s. May 5 termination = 3 DBP at Sloan’s; 1 DBP at Sieren’s.

Figure 1. Cover crop biomass at the two termination dates at the Sloan (Rowley) and Sieren (Keota) farms in 2017. Apr. 17 termination = 21 DBP at Sloan’s; 19 DBP at Sieren’s. May 5 termination = 3 DBP at Sloan’s; 1 DBP at Sieren’s.

“I was amazed at how well the corn planted into tall, thick covers,” Sloan said.

Across both farms, terminating the cover crop near the time of corn planting (3 or 1 DBP) often resulted in a yield reduction compared to when the cover crop was terminated about 3 weeks prior to corn planting (21 or 19 DBP) (Tables 3, 4 and 5). Higher N rates or varying the N strategy at the farms did not appear to overcome the yield reducing effects of terminating the cover crop near corn planting. The exception came where Sloan followed corn with corn and applied fall hog manure in addition to applying N fertilizer at corn planting and side-dress (Table 3). In this instance, terminating the cover crop three days before planting corn resulted in no yield drag compared to when he terminated the cover crop 19 days before planting corn.

N fert strategies sloan corn-corn 2017
N fert strategies sloan soy-corn 2017

Sieren applied 140 lb N/ac to all treatments but varied when he applied and in what form. Regardless of N strategy, he scored top returns when he terminated the cover crop 19 DBP (Table 5). Sieren saw greatest returns to N fertilizer strategy when the cover crops were terminated 19 DBP and yields were also greatest. Nitrogen costs were greatest and returns on investment were least when the cover crops were terminated 1 DBP.

N fert strategies tsieren 2017

“I really expected that this would be an example of ‘Don’t do stupid stuff’, which it kind of is!” Sloan said. “Just the physical environment those young plants grew out of, the shading and crowding of all that residue standing there for weeks, it’s not something a farmer would do. But it was a much closer competition than I expected. The corn after corn plot (Table 3) did not have the same level of competition between covers and corn (Figure 1), so it’s not the cover crop termination date, it’s the amount of cover crop biomass you’re planting into.” The cover crop in the corn-following-corn field at Sloan’s was comprised of winter wheat, oats, winter barley and rapeseed. The lack of cereal rye in that mix may have contributed to the less amount of biomass produced than in the corn-following-soybean field where the cover crop was winter wheat, winter barley and cereal rye.

For more details on this trial, read the full report: N Fertilizer Strategies for Corn Following Cover Crop. This project was supported by the Iowa Department of Agriculture and Land Stewardship, Division of Soil Conservation and the Natural Resources Conservation Service of the USDA.

For more information about this study and other studies as part of PFI’s Cooperators’ Program, contact Stefan Gailans at [email protected]