Sarah Carlson

Midwest Cover Crop Research Coordinator

Sarah Carlson joined Practical Farmers of Iowa staff in the fall of 2007. Sarah is the Midwest Cover Crop Research Coordinator. She helps transfer agronomic research about cover crops through articles, blogs and presentation materials while working to improve the support for cover crop 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 crop

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.

Continue reading

So, why do you want to grow cover crops? is a second webinar in the American Society of Agronomy series on cover crops focused on how to make sure farmers think about goals for cover crops before getting started. Length of the growing season affects the growth of cover crops after establishment, which affects the potential benefits that can be realistically expected from including cover crops into a production system.  Presenters from the central and northern Corn Belt will address their goals for, and their experiences with, incorporating cover crops into their operations plus share information about decision-making tools they use to improve their success with cover crops.  Information shared will be targeted to ag professionals who consult with farmers adding cover crops. Credits can still be earned just sign in through the ASA website.

so why do you want to grow cover crops

Click to download Dr. Gruver’s presentation.

Continue reading


Fred Abels shows off PFI’s newest merchandise. A wise quote from founder Dick Thompson, “Get along, but don’t go along.”


Click here to see more about Jack Boyer’s presentation.

56 farmers came to the Grundy County Fair on July 20, 2016 to learn more about cover crops and soil health at our “indoor” field day. Fred Abels, a long-time PFI member and Grundy County Commissioner helped plan another great workshop with ISU Extension and Grundy County NRCS. Continue reading


Oat cover crop seeded Sept 2015 near Knoxville, IA. Picture taken Dec 16, 2015.

Growing third crops in Iowa is of interest to many farmers but lack of obvious markets can reduce farmers’ enthusiasm about these soil building crops. Cover Croppers are using spring small grains, like oats, as fall cover crops sometimes mixed with cereal rye. Spring small grains seeded in the fall prior to September 20th in central Iowa can provide a lush, green burst of cover crop at harvest. Cattlemen like oats mixed with cereal rye to get some fall grazing too. But Cover Croppers comment that oats can be “finicky” and more delicate to establish than cereal rye. I asked the PFI Cover Crops discussion list what observations they had from aerial seeding or early fall direct seeding spring small grains like oats as cover crops. Could a new potential oat market be right in front of us or are oats to inconsistent for Cover Croppers to want to use? For example if oats were seeded as part of a cover crop mix on 10 million acres (the number of acres needed to meet Iowa’s Nutrient Reduction Strategy goals) we’d need about 125,000 acres to grow that seed. If cereal rye was a part of that mix we’d need about 285,000 acres to grow that seed. Total small grain acres in Iowa today is 100,000 and of that 55,000 is oats.

Cover Croppers on PFI’s Cover Crop email discussion list said this about oats:

—If the oats are not incorporated, they may need a couple of shots of rain to get going. One good rainfall event is enough for germination, but if they are exposed to the sun for very long (leaf drop is inconsistent), or the soil moisture is low, it won’t be enough to keep them alive. Had that happen in ’14 to me; lots of bare spots at harvest. I’m also looking at doing 1bu oats with 2bu rye in the fall this year. Could be good, could be bad. Long time till then! Continue reading

Each year more farmers in Iowa and across the Cornbelt are trying cover crops. Many start with a cereal rye cover crop planted in the fall after corn or soybean harvest or others contract with a pilot to fly it over the standing cash crop around Labor Day. Good planter setup can be key to avoiding negative impacts on corn or soybean yields.

 Mark Peterson near Stanton shared a picture of drilling soybeans in a tall rye cover crop.

PFI member Fred Abels sparked a conversation on our pficovercrops email discussion list about the best recommendations for properly closing a seed trench when planting after a cover crop. Fred shared, “I had two farmers call me today asking me for a better way to close their seed trench for soybeans. Both farmers [who I spoke with] have a good stand of rye and are having problems planting into the thick stand. One had combo units (trash wheels and no-till coulter), the other was using a coulter cart with a three point planter. I told the farmer with the combo units to try setting them deeper, it sounded like his trash wheels weren’t moving much out of the way. The other farmer was running 2 coulters per row, he was setting them deeper.” Continue reading