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.

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).

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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.

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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). Continue reading

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.


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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

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The Iowa Department of Ag and Land Stewardship announced today that they will be working with the Risk Management Agency and crop insurance companies in Iowa to reward farmers who are using cover crops on their farm. Farmers who have planted cover crops this fall or plan to still put out cereal rye on cornstalks going to a 2018 soybean crop can get a little extra help with those costs. Acres that are not currently in a cost share program from a local watershed program, IDALS county cost share or the NRCS are eligible and can be certified until 5pm January 15, 2018. Double check with your crop insurance agent that they are participating in the program and make sure to purchase the correct crop insurance product next spring to receive the discount. Acres certified through the IDALS program will receive a $5/acre discount on a the September crop insurance invoice. To read more go to the IDALS Cover Crop-Crop Insurance Program page and to sign up click here. Program rules are listed here and Frequently Asked Questions are addressed here. Questions about what cover crops to seed still late this fall? Get connected with Practical Farmers of Iowa by calling the office at 515-232-5661 or emailing [email protected]

Increasing rates of cover crop use on rented ground is the next frontier in improving water quality, promoting soil health and improving farmers’ resilience and not all of this rented land is privately owned. Local, state, and federal agencies own a large amount of land in the U.S. for the purpose of protecting natural resources and providing public infrastructure (flood management, water quality management, etc).

There are three main public agencies that own and rent farm land in Iowa: The Iowa Department of Natural Resources (DNR), the United States Army and the Army Corps of Engineers. For the DNR particularly, renting out this agricultural land is a balancing act between making sure that land is productive and creating and protecting wildlife habitat. The use of cover crops between cash crops on public rented ground addresses both of these goals.  Cover crops are planted to coincide with maturity of commodity crops like corn or soybeans and protect the soil until a new cash crop is planted in the spring so that there are living roots in the ground at nearly all times. This protects natural resources like water and soil by preventing erosion and nutrient leaching, and it provides and/or improves habitat for both aquatic and terrestrial species (see Wilcoxen et al. 2017).

A male farmer, dressed for cold weather kneels in a harvested field of corn where a lush, green cover crop is growing among what's left of the corn stalks

An Iowa Farmer inspects growth on his cereal rye cover crop, planted earlier this fall.

Despite the natural overlap between the goals of public agencies like DNR and the outcomes of cover cropping, it is still rarely implemented on their rented land. We spoke with land managers at several public agencies to better understand the barriers and opportunities for implementing cover crops on public lands. The following blog outlines three case studies where public land managers have added cover crop requirements in their leases and we conclude with some lessons learned that could help other public land managers implement cover crops on their acres. We found that the elements of a successful lease are: a cover crop requirement, basic best management safeguards and a penalty if cover crop is not established. To effectively manage these leases, land managers also require easier access to quality information about cover crops and should leverage public support for cover crops in their county. Continue reading

Cover crops are gaining new attention for their ability to reduce weed pressure in soybeans. Specifically, when seeding soybeans directly into a thick cover crop. In the past two years, farmer-researchers Jeremy Gustafson and Jack Boyer have documented reduced herbicide use when planting soybeans into a tall, thick cereal rye cover crop that they chemically terminated near the time of soybean planting (Cereal Rye Cover Crop Termination Date Ahead of Soybeans). In this new project, farmer-cooperators Jack Boyer and Scott Shriver investigated the effect of row-width on soybean yields when rolling a cereal rye cover crop. Boyer rolled select strips after terminating with an herbicide; Shriver used a roller-crimper to terminate his cover crop.

You can read the full report of this project here: Rolling Cover Crops and Soybean Row-Width.

Rolling covers and soy row-width cover

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The difference between a restored soil and unrestored.

The difference between a restored soil and not restored only after a couple years.

Guest Blog Post by Jonathon Gano, Director of Public Works for the City of Des Moines

Soil health is a key part of managing agricultural land with well understood benefits and a whole host of options.  Less well understood is the soil outside the front door of our homes.

Our lawns are often an afterthought when thinking about soil health but they are one of the first places a homeowner can work to improve water quality in our lakes and streams.  Healthy soil under our lawns can absorb and retain three times as much water as unhealthy soil.  Every drop of water lands somewhere – keeping that water where it lands just a little longer will slow it down, cool it off, and clean it up.

The first and best chance for a healthy lawn is careful management of Iowa’s abundant topsoil when the house is built.  Avoiding overcompaction and paying attention to the final grading to ensure adequate depth of the topsoil layer are key parts of a healthy lawn.

If, like most of us, you already live in a house with a yard, don’t give up hope – there is still a way to improve the soil without having to start all over again.

The most effective way to improve the health of the soil in our existing yards is the combination of deep core aeration with a top dressing of compost immediately following.  The compost fills in the holes left by the aerator, letting rich organic matter get deep into the soil profile.  That organic matter not only soaks up a lot of water, it helps feed the beneficial soil organisms in the ground and leaves the yard greener and more drought resistant.

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A group of farmers traveled to Ohio in August to spend a day at Dave Brandt’s farm. This blog accompanies the article in the Autumn 2017 Practical Farmer “Members Reflect on Lessons Learned in Ohio.”

By Sally Hertz Gran

Sally Gran Photos (28)

Sally Hertz Gran stands in the pasture at Berry Family Farm in Pleasantville, Ohio.

In this reflection, I will be highlighting some of the topics we dug into during the trip including crop rotation, seed selection (coatings and genetics), enterprise diversification, grazing cover crops, and how to engage more farmers in regenerative farming practices.

Ohio Soils 

Stefan and Meghan came prepared with activities to keep us occupied on the long bus ride, including a challenging game of Ohio trivia. Many of us were surprised to learn that soybeans are Ohio’s #1 crop. Shortly after arriving at Dave’s farm on Friday morning, we learned why—soybeans are not only commonly double cropped, with two harvests in the same calendar year, but some Ohio farmers grow continuous soybeans year after year.

This was the case for the first field the hayrack stopped at on Dave’s farm, in Carroll, Ohio. It had been in continuous soybeans for 25 years until just three years ago when Dave began leasing it. Prior to European settlement when most of Iowa was an ocean of densely-rooted prairie, Ohio was part of the eastern deciduous forest, which means that their soils are naturally higher in clay and lower in organic matter than Iowa soils. In the yellow clay of the recently formerly continuous soybean field, Dave increased the organic matter from 1% to 1.7% in just three years by implementing an extended rotation, planting cover crops, and practicing no-till. The three-year framework of this rotation (corn-cover-beans-small grain-cover) is applied throughout his entire farm.

Dave Brandt

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