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

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

earl and son matthew 3

Earl and son Matthew fill their drill to plant oats on their farm near Dunkerton, IA this past spring.

Practical Farmers of Iowa launched an Oat Pilot Project this year with seven farmer members who want to improve their ability to meet food grade oat market standards in the region by working together and sharing experiences. Earl and son Matthew Canfield farm near Dunkerton and planted 50 acres of various oat varieties this spring. Comments Earl, “[we] didn’t apply a fungicide last year and got along fine.” They are trying to learn how to grow heavy oats without pesticides. The biggest reason why oat farmers take a reduced payment when selling food grade oats is because the oats don’t meet the test weight requirements of food mills–they aren’t heavy enough. As shown in last year’s oat variety trial results 

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we can see that millers are looking for a very high quality product because their customers will be humans and most likely toddlers. Continue reading

Oats used to cover nearly 7 million acres in Iowa back in the 1960’s. Many farmers are adding oats back to their corn-soybean ground because of the numerous positive soil and economics benefits oats can provide the farm. Read the Top 5 Reasons for more small grains in Iowa. Many farmers are re-learning what it takes to treat this crop like a money-making cash crop. Basic agronomy is at the heart of setting yourself up for a successful year. After picking oat seed based on local variety trial results Vic and Eric Madsen, father-son farmer duo, in southwestern Iowa continue to hone in on their oat production skills. These last couple years they have been doing some on-farm trials to learn more. They have been working with Iowa State graduate student David Weisberger who has been collecting best management practices from oat farmers across the state.


Vic and Eric wanted to test out seeding oats super early–almost frost-seeding them versus a normal early April planting date to see if that improved the test weight and yield of oats on their farm. But on April 9th they realized that maybe their depth gauges hadn’t been set quite right. Some of the oats emerging had elongated mesocotyls (almost 3″ in length) while others had mesocotyls that measured 1in.


Says David Weisberger and Vic Madsen: “Establishing a good stand of oats is not unlike establishing any other crop. Two important early season factors to consider are appropriate soil temp and seedbed fitness.” Here are some things to remember: 

Soil Temp – Oat seeds will germinate at 40° F. However, like most plants, oats will germinate faster as soil temps increase, the goal is to balance an early planting date with biological limitations and the potential for seed predation or pathogen issues. While early planting dates usually mean higher yield and test weight potential, this spring has pushed the limit on what early planting can mean with some farmers planting in early to mid-March. There is little recent precedent for these early plating dates and much of the information that will be gathered this year will better guide us towards fine-tuning small grains production practices.
Seedbed Fitness – Planting into a firm seedbed and ensuring proper seed to soil contact will give your oats a good start. A firm seedbed should also go some ways towards modulation of seeding depth, which, for a small grain like oats should not exceed 1.5 to 2″. When assessing a recently emerged stand, dig around for a few plants; total plant length (length from the seed to tip of emerged first leaf) should not exceed 1.5 to 2″. If you are experimenting with early planting directly into stubble without cultivation or culti-packing, make sure you take a “practice pass” to ensure that seeds aren’t being placed too deep. This will give you a chance to modulate down pressure on your drill before planting too many acres. Remember that just like a corn or bean crop, uniform emergence is essential for establishing potential for both plants per acre and seeds per plant, early predictors of your “yield ceiling”.
Take aways – Keeping track of basic information like soil temp at planting, emergence, tillering and anthesis will not only help you to identify and understand key management stages but will force you to get out to your small grains field and get acquainted with an alternative crop. Whether you are new to small grains or a seasoned expert, walking fields and scouting plants is an important part of becoming a better small grains grower. Remember climate data and soil temps can be accessed through Iowa Environmental Mesonet. The more local information that is shared about what works and what doesn’t the better.

Are you trying oats again this year? Have any specific markets you are selling in to? Share that information with PFI staff as we build the knowledge of small grain markets in Iowa. Click here to take our survey.

Learn some tips here from PFI expert cover crop farmers.

This spring the cover crop is lush and really greening up much earlier than in previous springs. To be successful with corn following rye try these farmer tested tips:

“Apply acid equivalent (a.e.) of 1 lb/acre (28 oz WeatherMax or 43 oz of generic; I normally use less)”

“Low spray volume – check label (e.g. 5-10 gal/acre would be reasonable) – use right nozzles and height”

“Add AMS (ammonium sulfate; 4-6 lbs/100 gal). No UAN.”

“Add Non-ionic Surfactant if not included in formulation (NIS is in WeatherMax already).  No crop oil.”

“Don’t mix triazine or contact herbicides with glyphosate.”

“It is usually better to spray when you can rather than wait for perfect conditions with bigger more mature plants”

“Spray when the addition of day + night temps = 100”

“Starter w/ seed; 30-50# 2×2 band or 2” either side of the row.”

“Weed & feed @ termination plus early sidedress another option.”

”Knife 28% liq. N at a angle to the rows, 4” deep which is 2” deeper than the seed.”

“Rye by 6” tall plus inject UAN pre-plant, sidedress @ V6.”

​Contact the PFI office to find out how you can ask your cover crop questions and get solutions from other farmers around the state of Iowa.

Last month, Teresa shared this article on how to cut $100/acre for corn and soybeans with the PFI list serv. Several of you responded with some of the ways you’ll be cutting costs in 2016. First of all, seed cost seems to be the first way farmers are cutting costs. Many are moving from triple stacked hybrids and traited varieties to conventional ones. Another area is growing oats and rye. We are hearing from farmers that interest in growing small grains has increased because of the reduced input costs to grow small grains, resulting in better earnings per acre than on corn and soy acres. Both methods – moving to conventional hybrids and adding small grains to the rotation – help get farmers closer to reducing expenses by $100/acre.


  Continue reading

Oats were grown on 7 million acres in Iowa until the 1960s. Across much of the northern Cornbelt small grains like oats were once normal crops on the landscape. Oats provide farmers crop diversity allowing for reduced dependence on the markets of just corn and soybean. Oats improve soil health and reduce nutrient and soil loss from farm fields during the most vulnerable times of the year. Oats are good sources of animal feed and can provide straw for bedding. Oats also allow time for growing a nitrogen-fixing legume crop which can help grow corn with less purchased fertilizer or apply manure during the summer months to a high carbon straw crop.

PFI farmers and others have long lamented the lack of oats and other small grains on Iowa’s landscape. We have a history with this crop in Iowa. Whenever I hear farmers talk about growing oats when they were younger there is an emotional, visceral response in their voice. Given all this we need to make it work again in Iowa. To help get that started PFI, with funding from General Mills, Grain Millers, Albert Lea Seedhouse and the Sustainable Food Lab, worked with Iowa State University to evaluate 16 oat varieties for yield, test weight and food grade quality characteristics at the Northern and Northeast Research Farms.
 Four varieties were part of a second study at the Northeast Research Farm which compared with and without a fungicide application. To read more about the details and results click here.

Clover interseeded into corn

Clover interseeded into corn 2014 in northeast IA. Photo credit Loran Steinlage.

I presented results from a meta-analysis about cover crop interseeded into corn or soybeans at the American Society of Agronomy annual meetings in Minneapolis, MN. Click here to watch the presentation. Corn and soybean farmers have increased their acres planted to cover crops over the last six years (SARE 2015). Many use cover crops to reduce soil erosion, scavenge nitrogen and dissolved phosphorus, and improve soil health. Many farmers who have used cover crops for two to three years and have experienced less than desirable plant stands are testing seeding alternatives. Farmers have begun experimenting with seeding cover crops within 95 days of main crop planting.

At the beginning of this project the USDA-Risk Management Agency discouraged the seeding of cover crops earlier than physiological maturity of the main crop or later than 95 days after planting (DAP). But now the language has been updated. See the difference between Answer 1 and Answer 2 from the RMA website:

Q: Will over-seeding/interseeding a conservation cover crop into an insured grain crop affect insurability?
A1: No. As long as the cover crop is seeded near physiological maturity of the insured crop and the practice does not interfere with harvest of the insured crop. If there was any damage caused by over-seeding the cover crop (although unlikely), uninsured cause of loss appraisals would be applied to the insured crop. Continue reading