Cover Crop Research and Demonstrations in Iowa

By Matt Lechtenberg, Water Quality Initiative Coordinator

Cover crops are seeing a surge in popularity as farmers continue efforts to improve water quality and soil health on their farms.  A recent survey found that one in four Iowa farmers are using cover crops today.  The Iowa Nutrient Reduction Strategy, released in May of 2013 shows that cover crops are proven effective at reducing loss of nutrients from fields.  They’re also a critical component of improving and maintain soil health.   Cover crops are one of the only practices available to farmers that have been proven to achieve significant reductions in soil erosion plus nitrogen and phosphorus losses.  Cover crops are seeded either after harvest of a cash crop or often seeded into standing crops to improve growth of the cover crop to maximize the benefits.  These cover crops sequester nutrients that would otherwise be subject to loss through the fallow period between harvest and planting, the most vulnerable times for nutrient loss from Iowa’s soils.

In addition to limiting losses of sediment and nutrients from fields, there are many other benefits to integrating cover crops, such as increasing organic matter, increasing beneficial soil microbes, and more. Even with this knowledge of the benefits, there are challenges to implementing cover crops more broadly across in Iowa.   Researchers, non-governmental groups (NGOs), and farmers are leading these efforts on investigating, learning, and publicizing the proper management techniques and considerations for using cover crops in Iowa.

These groups are in no small part responsible for much of the buzz and interest generated in recent years around cover crops.  Their research and demonstration activities have led to invaluable information to help provide better understanding on proper management and other considerations to making cover crops work in farms across Iowa. 

With the support of public and private organizations and businesses these groups are working to increase the knowledge and understanding of cover crops and how they fit into Iowa’s cropping systems and weather patterns.  Through on-farm research and demonstration, these groups have experimented and documented proper management techniques for better informed decision-making. 

Below is a summary of the groups and locations of these activities currently being conducted in 44 of Iowa’s 99 counties.  Feel free to contact any of these groups for more information or if you’re interested in conducting trials or demonstrations on your farm.

Summary of Groups and Organizations surveyed and their lead staff members:

Cover Crop Solutions (CCS)  
Tracy Blackmer, Director of Research  
Mick Lane, Research Communications Manager  (800) 767-9441, ext. 107

Grassland Oregon (GO)
Brent Jones , Sales Manager  (503) 302-7538

Green Cover Seed(GCS)
Colten Catterton, Green Cover Seed Representative  (402) 984-1631

Iowa Cover Crop Working Group (CCWG), Iowa Learning Farms (ILF)
Elizabeth Juchems, Events Coordinator and Educator  (515) 294-5429

Iowa Soybean Association (ISA)
Tristan Mueller, Operation Manager-Agronomic Research   (515) 334-1075

Theo Gunther, Resource Management Specialist     (515) 334-1053

Iowa State University Research Farms and Extension & Outreach (ISUE)
Brian Lang, Extension Cropping System Specialist  (563) 382-2949

Mark Carlton, Extension Cropping System Specialist  (641) 932-5612

Mark Licht, Extension Cropping Systems Specialist  (515) 294-0877

Practical Farmers of Iowa (PFI)
Sarah Carlson, Midwest Cover Crop Research Coordinator  (515) 232-5661

Stefan Gailans, Research Scientist and Cooperators' Program Manager  (515) 232-5661

Soil Health Partnership (SHP)  
Ben GleasonSustainable Program Manager  Iowa Corn Growers Association (ICGA)  (515) 225-9242

Nick Goeser, Manager of Soil Health and Sustainability  National Corn Growers Association (NCGA)

USDA-ARS-National Lab for Agriculture and the Environment (ARS-NLAE)
Tom Kaspar, Plant Physiologist  (515) 294-8873

Below is a summary of groups and organizations working individually and often collaboratively on cover crop research and demonstration and a summary of their specific investigation:

Cover Crop Solutions (CCS)
Cover Crop Solutions is establishing a cover crop research and demonstration farm in Greene County.  The main focus of their work is to address proper management considerations for cover crops in Iowa and an assessment of some of the benefits relating to SCN reduction and nutrient catch/release. 

Grassland Oregon (GO)
Grassland Oregon has a research farm just south of Richland, IA in Keokuk County where they are conducting the following research and demonstration:

  • Testing planting dates of Balansa Clover, Crimson Clover and Berseem Clover in Corn. 
  • Broadcasting Balansa Clover and Berseem Clover into Soybeans and Field Corn to see how early the clovers can be planted and still produce a viable stand following harvest and the following spring.
  • Planted strips of Balansa Clover alone and in mix of grasses multiple planting dates to assess cold tolerance and performance in a mix. 
  • Research plots with cover crop mixes including Balansa Clover, Berseem Clover, Crimson Clover, Annual Ryegrass, Daikon Radish and Nematode Control Oilseed Radish seeded at various dates to assess biomass production and cold tolerance. 

Green Cover Seed (GCS)
A summary of the work Green Cover Seed is conducting with multiple farmers primarily in southwestern Iowa to investigate opportunities to incorporate cover crops in a host of cropping and livestock systems:

  • Cover Crop Answer Plot showcasing cover crops and comparing broadcast seeding into standing beans vs.  drilling after bean harvest– Montgomery County.
  • Side-by-side comparison of high biomass seeding mix vs. cereal rye only vs. no cover crop effects on water infiltration, soil erosion, soil temperature and yield – Fremont & Taylor Counties.
  • Summer cover crop mixes following winter cereal production for grazing – Fremont & Montgomery Counties.
  • Winter pea and winter lentil hardiness in varying planting conditions and seeding depths – Mills & Taylor Counties.
  • Increasing cereal rye yield performance – Fremont County.
  • Feasibility of full season sunflower crops – Decatur County.

Iowa Cover Crop Working Group (ICCWG)
ICCWG includes core members from the following agencies and organizations: Iowa Learning Farms, Practical Farmers of Iowa, Iowa State University Extension and Outreach, USDA-Agricultural Research Service, Leopold Center for Sustainable Agriculture, Iowa Department of Agriculture and Land Stewardship

  • Evaluation of cereal rye cover crop effect on cash crop yield and soil quality in Iowa using replicated strip trials – Butler, Greene, Guthrie, Ida, Tama, Taylor, Washington, & Webster Counties.
  • Evaluation of management techniques that will increase growth and improve the overall environmental benefits of cover crop seeding mixes in improving soil health and reducing nutrient losses – ISU Association Research Farms: Floyd, Hancock, Lucas,  O’Brien, Pottawattamie, & Washington Counties; Farmer Partners: Cherokee, Floyd, Carroll, Muscatine, Clay, Wright, Clarke, Page, Dallas, & Washington Counties
  • Plot scale evaluation of planting techniques for the successful establishment of cover crop mixtures and single species in Iowa. Three seeding techniques: 1) Seed delivered under cash crop canopy; 2) Seed broadcast above cash crop canopy; and 3) Seed soil incorporated after cash crop harvest – Hancock & Wright Counties.
  • Estimate the economic value of reduced erosion from cover crop use and to evaluate the value of cover crops for grazing and forage in a livestock operation.
    • Part A will update the “Value of Soil Erosion to the Landowner” publication written by Mike Duffy, ISU economics professor emeritus. Using the value of soil erosion and the amount of erosion reduced, an estimate of the economic benefit of using cover crops can be determined.
    • Part B will estimate cover crop biomass yield and feedstock value in a livestock operation for the major livestock regions of the state. Case studies for forage in a feedlot and grazing systems will be created and compared to other typical feed sources.

Iowa Soybean Association (ISA)
Overview of 2015 Cover Crop Research and Demonstration Projects for Iowa Soybean Association

  • 13 total replicated strip trials using different species and mixes in the Boone River Watershed – Humboldt, Kossuth, & Wright Counties.
  • 24 additional strip trials, 9 cover crop strip trials with nitrogen or manure comparisons across cover strips, and 6 cereal rye vs. annual ryegrass strip trial comparisons throughout the state – Audubon, Black Hawk, Bremer, Buchanan, Cherokee, Fremont, Hardin, Jasper, Lee, Marion, Mills, Mitchell, Osceola, Shelby, Tama, & Union Counties.
  • 10 trials supported by IDALS in the Upper Cedar and Nishnabotna River Watersheds. The project is using soil health testing and cover crop biomass sampling to improve knowledge of cover crop effect on soil.

All strip trials evaluate different cover crop management practices on crop yield and/or soil health.  Trials include both aerial broadcast and drill seeding.   Results of replicated strip trials are posted at after completion of harvest and analysis. All projects with results from the previous year are presented at the annual ISA Research Conference held in February in Ames, IA. 

Farmers interested in conducting on farm replicated strip trials using cover crops or other management techniques can contact the On-Farm Network staff.  A current opportunity for farmers in the East and West Nishnabotna River watersheds for soil health testing is available for the spring of 2015. Anyone using cover crops who are interested in trying soil health testing can contact Theo Gunther at or 515-334-1053 for more information.

Iowa State University (ISU) Research Farms and ISU Extension and Outreach (ISUE)
The following list of projects regarding cover crops are being conducted at various Iowa State University research farms across the state. Written articles on some of them can be found at .

  • Corn and soybean cover crop by nitrogen study, Armstrong Farm – Pottawattamie County.
  • Cover crops in an organic crop rotation, Neely-Kinyon Farm – Adair County.
  • Cover crop evaluations in a corn/soybean rotation, Armstrong Farm – Pottawattamie County.
  • Cover crops for vegetable production, Armstrong Farm – Pottawattamie County.
  • Organic vegetable production with cover crops, Neely-Kinyon Farm – Adair County.
  • Residual herbicide effects on cover crops, Armstrong Farm – Pottawattamie County.
  • Cover crop demonstration, Horticulture Station – Story County
    • Effects of fall cover crops on spring potatoes
    • Effects of summer cover crops on fall cabbage production
    • Effects of summer cover crops on fall lettuce production
    • High tunnel cover crop study
    • Prairie cover crops, Horticulture Station.
    • Cereal rye cover crop use for pumpkin production, Muscatine Island Farm – Muscatine County.
    • Evaluation of cover crops and nitrogen rates on corn, Northeast Farm – Floyd County.
    • Cover crop tolerance to herbicide, Southeast Farm – Washington County.
    • Cereal rye cover crop study, Southeast Farm – Washington County.
    • Three species cover crop termination method demonstration, Field Extension Education Laboratory (FEEL) – Boone County.
    • Comparison of biofuel cropping systems, Agronomy Farm, Boone County.
    • Suitability of winter canola for enhancing crop rotations in Iowa, Agronomy Farm, Boone County.
    • Improving organic no-till systems, Agronomy Farm, Boone County.
    • Nitrogen fertilization of corn with a rye cover crop, Agronomy Farm, Boone County.
    • Rye cover crop demonstration, Western Farm, Monona County.
    • On-farm trial of clover and radish after corn silage, Monona County.
    • Residual effects of cover crop, Sioux County.
    • Cover crop on-farm trial, Howard County.
    • Cover crop on-farm trials, Cass County.
    • Rye cover crop trial, Allee Farm, Buena Vista County.
    • Surface runoff trial with cover crop, Northwest Farm, O’Brien County.
    • Cover crop x tillage x N timing trial, Northwest Farm, O’Brien County.
    • Soybean maturity x cover crop trial, Northwest Farm, O’Brien County.

Practical Farmers of Iowa (PFI)
PFI has a wealth of information on cover crops relative to Iowa based on years of on-farm data collected from farmer cooperators.  Many reports are available on past and current on-farm research at If interested in designing your own trial or participating in a trial listed please contact PFI staff today.

  • Summer squash following cereal rye with and without tillage – Story County.
  • Quick turnaround summer cover crop – Bremer & Cedar Counties.
  • Grazing cover crops – Audubon & Story Counties.
  • Diverse cover crops with cereal rye grain production – Adair, Audubon, Buchanan, & Shelby Counties.
  • Third crop economics with red clover versus a fall cover crop mix – Audubon, Buchanan, Shelby, & Washington Counties.
  • Multiple mixes at multiple seeding times into corn and soybean – Hardin County.
  • Yield response to ”planting green": corn planted to cereal rye cover day of termination – Jasper County.
  • Cereal rye seeded into seed corn before/after defoliant – Tama County.
  • Cover crop following early vs. normal soybeans (2.0 vs. 3.0) – Mills County.
  • Cover crop following early vs. normal corn (103 vs. 109 RM) – Mills County.
  • Soybean yield after planted into standing rye – Humboldt County.
  • High versus low sidedress nitrogen following a cereal rye cover crop – Boone & Wright County.
  • Cover crop species trial '13-14' – Audubon, Boone, Crawford, Fayette, Mills, Montgomery, Ringgold, Pocahontas, Pottawattamie, Union, & Washington Counties.
  • Cover Crop species trial '14-'15 – Audubon, Boone, Cass, Crawford, Fayette, Mills, Montgomery, Ringgold, Pocahontas, Polk, Pottawattamie, Union, & Washington Counties.
  • Cover crop mix on prevent plant effect on corn yield – Bremer County.
  • Herbicide carryover injury to cover crops – Boone County.

Soil Health Partnership (SHP)
Partnership between the National Corn Growers Association, Monsanto, Walton Family Foundation and the Nature Conservancy to measure and communicate the economic and environmental benefits of different soil management strategies, and provide a set of regionally specific, data-driven recommendations which farmers can use to improve the productivity and sustainability of their farms.  Specific soil health practices to be evaluated include cover crops, reduced tillage, and nutrient management.

  • Currently working with 5 farmers in Iowa to identify, test and measure management practices that improve soil health and benefit farmers’ operations – Allamakee, Bremer, Kossuth, Story, & Wright Counties.  More farmers will be added each year for five years with a goal of 100 farms across the Corn Belt.
  •  Participating farmers will use their individual results to communicate the economic and environmental benefits of cover crops, reduced tillage, and nutrient management via publications, field days, and conferences.

USDA-Agricultural Research Service (ARS), National Lab for Agriculture and the Environment (NLAE)

  • Cereal rye and oat cover crop effects on nitrate leaching in a tile-drained field – Boone County.
  • Long-term cereal rye cover crop effects on soil properties in a corn silage-soybean rotation – Boone County.
  • Cereal rye cover crop effects on corn seedling root diseases – Boone County.

This listing provides a great resource for those interested in learning more about cover crops and related information.  If you’re interested in learning more about what these groups are working on, please feel free to contact them.   To request additional information or request conducting this demonstration and/or research on your own farm, contact information for each group is provided.  The different cropping systems and weather variability in the state allows for no shortage of opportunity to try new species and mixes of cover crops to experiment and find out what works best in an individual farmer’s cropping system.  If one of these groups isn’t working in your area, contact any of them to express interest in establishing a trial or demonstration project in your area.