Sarah Carlson

Midwest Cover Crop Director

Sarah Carlson joined Practical Farmers of Iowa staff in the fall of 2007. Sarah is the Midwest Cover Crop Director. She helps transfer agronomic research about cover crops and small grains through supply chain projects, articles, blogs and presentation materials while working to improve the support for cover crop and small grains research. She also serves as an agronomist on the staff transferring ideas for solutions to integrated crop and livestock concerns from farmers’ stories, results from on-farm research projects and her own knowledge as a trained agronomist.

Sarah co-majored in Biology and Geography at Augustana College in the Quad Cities graduating in 2001 with a BA degree. Following graduation Sarah joined the Peace Corps as an Ag-business and Ag Extension volunteer. She lived in the southern highlands of Ecuador in South America for 2 1/2 years. Sarah returned to the Midwest in 2004 and began her Masters Program co-majoring in Sustainable Agriculture and Crop Production/Physiology in Iowa State’s Agronomy Department. She graduated in the spring of 2008 with an MS degree.

Sarah and her husband Oscar have four children between them, Rebeca, Oscar, Sadie and Tenoch. They enjoy cooking, traveling and exploring the Iowa countryside.

Blog posts


Cover crops are an important practice to sustain the natural resource base upon which agriculture depends, the soil. Cover crops help provide year-round cover to soils which not only reduces erosion from wind and water but also captures fugitive nutrients like nitrate-nitrogen and dissolved phosphorus before they pollute nearby water bodies. In the Cornbelt, farmers have increased their acres of cover crops over the past four years as reported in an annual survey conducted by the Conservation Technology Information Center and the Sustainable Agriculture Research and Education program (2016). But even with this increase in popularity little germplasm improvement for cover cropping characteristics has happened. The species farmers are planting today for cover crops have had little germplasm selection for specific cover cropping characteristics, presenting significant opportunities to improve the environmental and agronomic benefits of cover crops.

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To better understand what cover cropping characteristics farmers want and need to improve their success with cover crops a review of the four annual SARE/CTIC surveys was conducted; specifically on the sections about Challenges and Benefits. In the first three years of the survey farmers were provided with a set of 11-15 Challenges to rank (CTIC and SARE 2013, 2014, 2015). In Year Four (2016), survey respondents were provided 11 Challenges to rank as a Major, a Minor or No Challenge on their farm.  Cover crop farmers ranked 10-17 different Desired Cover Crop Benefits as shown in column two.

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photo from Wendy cropped

Read results from PFI’s newly released “Oat Variety Trial 2016.” PFI staff working with Albert Lea Seedhouse, General Mills, Grain Millers, the Sustainable Food Lab and Iowa State University chose 16 oat varieties to test at the Wendy Johnson farm near Charles City, IA and Iowa State University’s Northeast Research Farm (Nashua) and Northern Research Farm (Kanawha).

In a Nutshell:

  • Small grain crops, like oats, are seeing renewed interest by farmers in Iowa. Iowa was once a nationwide leader in oats production, but many farm families have not grown them for a generation or two.
  • 16 oat varieties were screened at two Iowa State University research farms and one commercial farm.

Key Findings:

  • Saber, Reins, Betagene, Deon, Badger and Excel varieties were among the top performers in terms of yield at locations.
  • Reins and Shelby 427 at Kanawha met the test weight requirement (38lb/bu) identified by food processors.

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PFI board President Mark Peterson, PFI Executive Director Sally Worley, CDI Executive Director Clare Lindahl and CDI Project Manager Courtney Slagle take a selfie in the PFI Booth.


PFI members Dan Hayes (front) and Mark Peterson (back) talk to farmers about cover crops at the PFI booth at FPS.

The Farm Progress Show was in Boone, IA last week. Practical Farmers of Iowa has been hosting a booth at the show the past three times its been held in Boone, IA. The booth was filled with cover crop plants, PFI materials and most importantly PFI farmer experts who shared advice about cover crops with other farmers. This year’s show was different. It felt different when staff and PFI farmers asked others if they were using cover crops. Or if they had considered using them. More farmers came into the booth this year than in previous years. More farmers asked our PFI crew in-depth practical questions about how to make cover crops work on their farms. There was genuine interest about this important conservation practice.

Have we turned the corner on acceptance of cover crops?
It really seemed so. In addition to all the great conversations at the PFI booth in the Varied Industries Tent. We also partnered with Conservation Districts of Iowa to show off cover crops in the field and helped seed a cover crop plot near Conservation Central. Other PFI farmers also staffed a tent nearby that plot where they could show off cover crops. If you missed the show see below the farmers who staffed the booth and some of the topics they talked about.

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This summer cover crop experts from Indiana wrote an extension publication reaction to farmers concerns about plugged tile lines being caused by cover crops. I asked the question, have you had cover crops plug your tile lines to our PFI cover crop email discussion list. Below are some of there reactions. In general farmers seemed to conclude that roots are roots and they can clog tiles. Some farmers concluded that a plugged tile from any type of root might mean a bigger issue with that tile. Continue reading

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Cover crop established after corn in Iowa. Photo credit IDALS.

One Stop Cover Crop Service available in Boone and Story County:

We take the hassle out of building your soil health

Prairie Rivers of Iowa, in partnership with the Boone and Story County Soil and Water Conservation Districts, is taking the hassle out of fall cover crop application. You tell us what you want for your fields, and we’ll book the service and buy the seed. You’ll receive only one bill in the end, and hopefully, some peace of mind. Continue reading

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Click here to read more about seeding recommendations from PFI’s multi-site cover crop variety trial.

Cover crop planting season is coming for the northern Cornbelt! Many farmers are gearing up to aerial seed cover crops but how can we make sure we have green fields in the fall during harvest?

2012 drought anderson

Aerial seeded cereal rye cover crop into standing corn, drought 2012. Photo courtesy Nathan Anderson Aurelia, IA.

cattle and grazing anderson

September 7th aerial seeded winter small grains + mustards and other brassicas and forage barley make a nice green carpet at harvest. Photo courtesy Nathan Anderson Aurelia, IA taken October 5.

Take some hints from cover cropper Nathan Anderson who farms near Cherokee, IA. In Nathan’s part of the state, sufficient rainfall is critical to aerial seeding cover crops. “What we don’t want is overseeding cover crops into a thick, dark corn canopy. We need more sunlight on the canopy floor followed by a good rain to achieve successful cover crop establishment. Don’t get started too soon.”
Farmers might be feeling a push from pilots who haven’t needed to spray too much for aphids this season. But even if a pilot is available if the corn isn’t we risk the chance of seeds germinating and not surviving.

Steps for aerial seeding cover crops:

1)Check when your corn is predicted to reach black layer. University of Missouri has a handy calculator to help you. Try to overseed within a couple days through Mid-September. For soybeans overseed when you see first yellow leaves.

2) Is your seed secured? Did you contact your pilot and your fields have been outlined? Use Practical Farmers cover crop business directory to find seed and seeding services.

3)Is rainfall predicted? Timely and sufficient rainfall is critical. Farmers observe that at least 1/2″ rainfall is needed followed by another storm to get the seed germinated and established,

4) An on time harvest is the last component for success. Getting the crop off helps the cover crop grow.

5)Have time to drill the crop following grain harvest? A drilled cover crop will almost always be more consistent than an aerial seeded cover crop but many times we are short on labor and time during harvest to be able to chase the combine with a drill full of cover crop seed. If the above steps are taken aerial seeding cover crops can result in successful establishment.

Other resources:

Check out Tim Smith’s video of aerial seeding cover crops on his farm into standing soybeans.

Check out Jacob Bolson’s aerial seeding blog last year too.

Webinar: Successfully Aerially Seeding Cover Crops.

The third webinar in the American Society of Agronomy series discussed the financial return on investment when adding cover crops to a predominately corn and soybean system. Show me the Money, Can cover crops pay? What economic data is available on changes in costs and revenue when cover crops are added to your system? Learn the cover cropping system Ken Rulon, farmer from Arcadia, IN is using on his farm and he determines the return on investment of adding cover crops. Also hear from Lauren Cartwright with Missouri NRCS about a partial budgeting tool to help farmers better understand changes in costs and revenues when adding cover crops to their farm. CEU credits are still available and are free. Continue reading

In February of 2016, the American Society of Agronomy (ASA) held a series of webinars for CCAs and others in the Midwest to learn more about making cover crops work. This webinar, Managing for Cover Crops: Don’t Forget the Agronomic Basics, will focus on the agronomic adjustments researchers/producers/CCAs need to remember when adding cover crops to the current farming system. Learn from Trent Sanderson, farmer from Clare, IL, about what agronomic considerations they remember when managing cover crops. Hear about planting date, seeding method, seeding rate, species selection, pest management, herbicides, and the effects on the following crop, among others. Learn from State of Missouri Extension Weed Scientist, Kevin Bradley about the effects of herbicide carryover on cover crops, how to terminate cover crops, and what cover crops actually do for weed control. Information shared will be targeted to ag professionals who consult with farmers adding cover crops. CEU credits are still available if you log in through the ASA website.

Kevin Bradley

Click on this picture to download Dr. Bradley’s presentation.

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