Ten-Year Cover Crop Study and ILF 2018 Cover Crop Report: Good News and Less-Good News

ILFHeader(15-year)Iowa Learning Farms and Practical Farmers of Iowa (PFI) recently published the ten-year results of an on-farm field research study about cover crops. And ILF recently released the cover crop statistics it has been tracking for many years. The results of both these newsworthy items include both promise and troubling points. The cover crop study indicates no loss of yield, and limited improvements – not a homerun, but not a strike-out either. The cover crop report shows 880,000 acres in 2018. More than 2017, but a significant slowing of acres planted in cover crops statewide – for the second year in a row.

Farmers and researchers seem to hold the strongest opinions about cover crops – and these opinions are not always the same. Since 2008, before anyone was really talking about cover crops, ILF and PFI launched a long-term on-farm field research study to help understand the impacts of planting cover crops on soil health, yields and nutrient/soil leaching.

As the ILF project lead, I get to work with the farmer partners as well as colleagues at PFI. Stefan Gailans, PFI project lead, noted that research studies such as this are often in response to requests and questions from working farmers looking to improve or change how they operate. A goal of this project is to address the question, “How does a cereal rye cover crop affect cash crop yields?”

To our knowledge, this is the only study in the Midwest that has spanned 10 years of working with farmers on their farms. One challenge for this kind of study is that these farms are run by real people making real-life decisions every day and every year. Operating a farm business sometimes leads to actions and decisions that are not what the researchers would prefer, but sometimes lead to learning by all parties.

Working with farmer-partners in conducting research at field scale, lends weight to the outcomes reported. Farm operators do read studies and look for anything that will give them a performance edge. But, many also like to share tips and tricks with each other, and experiment on their own.

These farmer-partners are not content to only participate in the research project, they have also become strong leaders on cover crop implementation, traveling all over the state to talk at field days and conferences, as well as hosting field days. This is indicative of the trust farmers have in peers, and the broad-based desire to share knowledge and learn from each other. We are always seeking participants and sites for field days to promote conservation techniques such as cover crops. Please reach out to ILF if you are interested in learning more or hosting.

The group of cooperating farmers has varied over the study term, comprising 12 operating farms in Iowa. Taken as a whole, the data collected covers 68 site-years with cereal rye cover crops planted before both corn and soybean cash crops.

The number one negative perception we hear: Cover crops reduce yield.

Cooperators have reported that in 61 of 68 site-years properly managed cover crops had little to no negative effects on corn and soybean yield, and there were improvements in soybean yield in eight site-years and corn yield in three site-years.

Winter_Rye_Effect_on_Corn YieldWinter_Rye_Effect_on_Soybean YieldWhile we don’t claim huge yield gains, it’s becoming quite clear that when done consistently and managed well, cover crops don’t substantially impact yields. And there are substantial benefits beyond yield that help to offset the upfront investment in cover crops.

 So where do we find the financial upside?

We cannot argue with the logic that cover crops take investment to plant in the fall, and terminate in the spring, however reaching the no yield impact determination allows us to start at zero instead of in-the-hole when assessing return on investment.

Farmers with an inherent values-based desire to improve water quality and conserve soil naturally consider cover crops as a long-term investment in the environment that will bear fruit in many ways. This isn’t saying that they aren’t concerned with the operational costs, just that they tend to roll it into the overall cost of doing business.

For those that are more focused on the exact economic impacts, we suggest a longer-term viewpoint. Soil erosion may take years, but with the loss of each fraction of an inch from the fertile topsoil, the production capacity of a field will go down.

To learn more about cover crop field days in your area, or if you are interested in hosting one on your farm, please contact me ejuchems@iastate.edu

For more detailed information on the project, see “Winter Cereal Rye Cover Crop Effect on Cash Crop Yield” on our website.

Liz Juchems

Importance of Cover Crops Following a Drought

With corn and soybean harvest approaching, many folks are planting their cover crops, or planning to plant their cover crops as soon as they can. The biggest question we are getting these days is whether cover crop seeding recommendations need to be changed because of the dry conditions in many parts of Iowa.

Quote1

Drilled Cereal RyeThe quick answer is that cover crop seeding recommendations remain the same: aerial and broadcast seeding methods require a slightly greater seeding rate than drill seeding. If there is not enough soil moisture or a rain within a week of seeding, there will be diminished and variable stand establishment across the field. To minimize this, you might consider drill seeding over aerial and broadcast seeding. Typically, drill seeding results in more uniform stands across the field with the consequence of less fall biomass production due to a later seeding date. Even later planting due to drilled seeding results in soil health improvements from spring growth of winter cereals.

Regardless of how you are going to seed, it is important to get the cover crops out inCereal Rye the fields. Cover crops play a crucial role in building soil moisture by improving water infiltration and aggregate stability. Additionally, they have the added benefit of scavenging residual soil nitrogen. Winter cereal grains such as winter rye, wheat, and triticale, are the preferred cover crop for their exceptional ability to use residual soil nitrogen. This is an extremely important characteristic following drought years where nitrogen leaching and crop nitrogen uptake are both potentially lower.

Quote2

Web

Gilmore City research site that measures difference in nitrate levels under different treatments

Iowa State University research conducted by Dr. Matt Helmers at Gilmore City, Iowa, show seasonal spring nitrate concentrations from 2011 to 2015 were the highest in 2013 (wet spring following a dry 2012). In the conventionally tilled system, nitrate concentration in drainage was 23.7 mg/L. When cover crops were added to the system, the nitrate concentration was reduced by 51% to 11.5 mg/L.

Web

Left and center: Exterior of sumps which are connected to the tile drainage lines in each plot. Right: Interior of a sump. The sump shows a meter reading for each pump located in each plot. Water samples are taken from each pump to be tested for nitrates.

While establishing cover crops in dry conditions may be a challenge, these are the situations where the impact of cover crop can provide big benefits.

Mark Licht

Mark Licht is an Iowa Learning Farms team member and Assistant Professor and Extension Cropping Systems Specialist at Iowa State University.

 

 

 

Reducing Soil Erosion with Cover Crops: New Infographic

Iowa Learning Farms is pleased to announce the release of a new infographic publication titled Reducing Soil Erosion with Rye Cover Crops.

This visually engaging document highlights one of the biggest benefits of cover crops — the ability to significantly reduce soil erosion. Based upon long-term cover crop work conducted by Korucu, Shipitalo, and Kaspar, colleagues at the USDA-ARS National Laboratory for Agriculture and the Environment here in Ames, this study looks specifically at one of Iowa’s most popular cover crops, winter cereal rye.

The USDA-ARS team conducted in-field simulated rainfall studies on plots with and without cereal rye cover crops, and their findings are powerful in terms of quantifying erosion reduction – 68% less sediment in surface runoff water with a rye cover crop. Further, the amount of surface runoff water decreased, while the amount of water infiltrating was found to increase with the cover crop.

This study was conducted in central Iowa, in the heart of the Des Moines Lobe, on land with a 2% slope. Substantial erosion reductions were found here with rye cover crops — consider the benefits of cover crops to reduce erosion on more sloping lands across the state!

The full infographic is available as a free PDF download on the Iowa Learning Farms website. Clicking on the image below will also take you right there.

Ann Staudt

A Cover Crop Snapshot

In the last two weeks, Iowa Learning Farms team members have visited five of our cover crop demonstration sites located on ISU Research Farms to check on spring cover crop growth and prepare our suction lysimeters for water monitoring this spring.

I posted photos from my trip to the Armstrong Research Farm on March 27, but now that we’ve been to each site, I thought it would be interesting to see a snapshot of how our cover crops (specifically, the over-wintering cereal rye) are doing across the state.

Here are the pics in chronological order of our visits:

Armstrong(Lewis)

McNay(Chariton)

???????

Crawfordsville

Nashua

How are your cover crops doing this spring?  We’d love to see your spring cover crops photos… share with us on Facebook, Twitter, or send via email to ilf@iastate.edu.

Ann Staudt