Redefining the Field Edge

Final report for LNC18-409

Project Type: Research and Education
Funds awarded in 2018: $199,351.00
Projected End Date: 09/30/2022
Grant Recipient: Iowa State University
Region: North Central
State: Iowa
Project Coordinator:
Dr. Mark Licht
Department of Agronomy, Iowa State University
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Project Information


Iowa State University's Conservation Learning Group seeks to reevaluate the traditional "field edge," investigating the long-term productivity and profitability of in-field low lying depressional areas. While traditionally planted to agricultural row crops, in the majority of years these marginal areas require significant inputs resulting in only modest crop yields and returns on investment. Can these marginal land areas be taken out of row crop production and transitioned to perennial vegetation to increase the return on investment with fewer acres and less risk? In addition, what benefits can be realized for water quality, soil health, and wildlife habitat?

This hybrid research and demonstration project seeks to work with five farmers to evaluate the feasibility of planting edge-of-field depressional areas to perennial vegetation, investigating the related agronomic, economic, water quality, soil health, and wildlife implications. Further, the project team will conduct an in-depth social science assessment to better understand the attitudes and perceptions of farmers and landowners towards conservation practices and alternatives to traditional grain crops, specifically looking at barriers to adoption and measuring how attitudes change in the five farmers over the course of the project. Project findings will be presented in a comprehensive, engaging, and accessible case study format (including printed publications, infographics, video, and audio components), which will be broadly distributed to farmers, landowners, agricultural and natural resource professionals, and college students via the Conservation Learning Group, Iowa State University Extension and Outreach, and additional conservation partners across the North Central Region.

Project Objectives:

Participating farmers and users of educational materials will learn how to make informed decisions regarding implementation of land use change through multi-year analysis of in-field productivity and profitability. Learning outcomes include an increased understanding of agronomic, economic, environmental, and wildlife benefits of transitioning small edge-of-field depressional areas out of row crop production. The anticipated action outcome is for high risk, low profitability field areas to be converted from annual row crop production to perennial vegetation, minimizing risk and maximizing farmer profits, while realizing water quality, soil health, and wildlife benefits provided by targeted plantings of diverse perennial vegetation.


The prairie pothole region runs from central Iowa north and west into Minnesota, South Dakota, North Dakota, and across the plains of Canada, covering nearly 173 million total acres. The region is characterized by abundant prairie potholes, small depressional wetlands that can be permanent, semi-permanent, seasonal, or temporary. Row crop intensification and drainage systems in the late 19th and early 20th centuries gave rise to a dramatic decrease in wetlands in the region by an estimated 95 to 99% (Bishop, 1981; Bishop and van der Valk, 1982; Bishop et al., 1998). By the early 1980s, the area of wetlands in Iowa’s prairie pothole region was less than 30,000 acres, down from an estimated 1.3 million acres historically (Bishop et al., 1998; Miller et al., 2009).

In recent years, precision technologies, big data decision support tools, and equipment advancements have made it easier than ever to identify high risk/low productivity and low sustainability areas that can be converted from annual row crop production to perennial vegetation, and easily farmed around when converted areas are near field edges. Couple these abilities with efforts to improve soil health and reduce nutrient losses, and fine-scale, targeted land use change to perennial vegetation offers great potential to improve overall field profitability and provide wildlife habitat while reducing risk profiles associated with poor return on investment, nutrient losses, and soil degradation (e.g., Schulte et al. 2017). Brandes et al. (2015) speculates that planting low-input perennial vegetation into low-yielding areas of fields would increase overall cropland profitability by 80% while possibly providing large ecosystem services such as wildlife, pollinator, and monarch habitat.

One of the major constraints of converting prairie potholes from row crop production to perennial vegetation is location within the field. Prairie potholes along a field edge can be farmed around relatively easily with precision technology and machinery advancements. However, farming around prairie potholes in the middle of the field presents difficulties and inefficiencies associated with farming around small areas. The true opportunity lies in identifying and converting prairie potholes along the field edge where the potential for sediment and nutrient loss is greater, as well as potentially impacting lower yielding areas associated with end rows. Field edges also facilitate access for easier establishment, maintenance, and potential use of perennial vegetation for haying or grazing.


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By using within-field profitability analysis, the whole field profitability will be increased when less profitable field areas are transitioned from row crop production to perennial species.

Materials and methods:

The Conservation Learning Group project team approaches this project with four objectives:

  1. Partner with five farmers to identify management practices and inputs from fields containing farmed potholes/depressions.
  2. Evaluate the feasibility of establishing diverse perennial vegetation stands in high risk/low profitability areas at the field edge and make recommendations on best management practices.
  3. Establish land use change demonstrations of perennial vegetation in depressional areas following best management practices from objective 2.
  4. Assess attitudes and perceptions of farmers and landowners towards perennial vegetation and alternative crops.

(Objective 1) The project team will work closely with five farmers to collect historic agronomic and economic data, including field management practices, seed and fertilizer inputs, grain yields, and revenue. The evaluation of these data will be conducted using SMS Advanced from Ag Leader Technology to generate profit zones within each field for the current management scenario. This objective is driven by the farmer partners’ willingness to provide yield monitor files, crop production practices, and crop input costs. The project team will work closely with each of the farmer partners to evaluate the within-field profitability and to identify low profit field areas.

(Objective 2) The project team will investigate 10 potholes currently planted in perennial vegetation as a result of enrollment in the Conservation Reserve Program (CRP). Field vegetation sampling routines will be conducted through late spring and summer of 2020 to assess vegetation diversity and gauge establishment success. Additional bird, monarch, and milkweed surveys will be conducted to assess habitat success. As part of this objective a listening session or survey will be held to gain insights into the successful establishment of diverse perennial vegetation.

(Objective 3) In consultation between the farmer partners and the project team, 3-5 field areas will be converted from annual row crop production to perennial vegetation based on the within-field profitability analysis. Each field area selected for conversion will be 1-3 acres in size. The project team will work closely with each farmer to target conversion areas to be located near a field’s edge so regular field operations can proceed either around or through the area with minimal disruption. Field assessment will be conducted in Years 2 and 3 of the project to determine and document agronomic, economic, and environmental viability. In-field assessments will compare field areas of land use change with similar areas that remain in row crop production through a paired comparison approach. Soil health will be assessed in Year 3 of the project via chemical analysis of the soil, combined with the Solvita and Haney tests evaluating respiration and other soil health metrics. Soil nitrate samples will be collected and assessed at the 0-1 and 1-2 foot soil depths in 6- to 8-week intervals throughout the growing season, providing a temporal picture of soil nitrate availability and nitrate loss potential over the course of the growing season. Perennial plant establishment and diversity will be assessed in the spring, summer, and fall following establishment through the end of Year 3.

(Objective 4) An in-depth social science assessment will be conducted, utilizing such techniques as participant observation, interviews, and the Rapid Needs Assessment and Response technique, to evaluate attitudes and barriers to conservation practice adoption and alternative cropping systems. In the first year of this project, the Conservation Learning Group team will conduct three Rapid Needs Assessment and Response (RNR) workshops in order to assess the attitudes and perceptions of farmers and landowners toward perennial vegetation and alternative crops. These workshops will be held at different locations throughout Iowa with a goal of 25-30 participants per workshop. We plan to give the farmers a journal and camera so that they can record their observations and the changes to the converted field. We will also do pre-, mid- and post-assessment interviews with the 5 farmers to be able to understand changes in understanding over the course of the project and also to obtain feedback in terms of how their neighbors might be viewing this project—in other words, what are they hearing in the “coffee shop” regarding transitioning those areas away from row-crop farming. Through detailed evaluation of field days and workshops, we will also assess attitude and perceptions of the farmers and landowners in attendance. We are anticipating 160+ farmers will attend our four field days.

Research results and discussion:

(Objective 1) Field profitability analysis was completed using SMS Advanced coupled with the cooperators’ yield monitor files for 2019, 2020 and 2021 project growing seasons. Additional historic profit analysis was completed for the 2-15 years of data available provided by the farmer partners.

(Objective 2) Thirteen potholes with established perennial vegetation, planted via prior CRP enrollment, were identified in Boone and Story County, Iowa. Vegetation assessments were conducted on these sites in 2019, 2020, and 2021. These same grassland vegetation clusters were used for three rounds of bird, monarch, and milkweed surveys as an indication of vegetation quality in 2019, 2020, and 2021. Twelve species of breeding birds were identified using these established sub-field perennial plantings, including several species of conservation concern in agricultural landscapes. Established perennial vegetation communities appeared likely to support monarchs and other pollinators by provisioning suitable densities of milkweed and nectar resources. The average distance to milkweed across all fields and all years of monitoring was 3.6 m (95% CI = 3.0, 4.3). The mean number of nectar resources per acre was 205.8 (95% CI = 128.2, 283.4). Low nectar density in the early summer is a potential constraint of current vegetation communities to supporting monarch and other pollinators and merits additional research. Future planting efforts could prioritize early blooming species, along with later-blooming species more conventionally included.

Additionally, a survey instrument was developed targeted to private lands wildlife biologists at the start of this project, to gather their insights into best practices for successful establishment and maintenance of perennial vegetation. From March to April 2019, the survey was distributed to 70 private lands wildlife biologists. There were 52 respondents, in addition to the project team carrying out individual consultation with an Iowa DNR private land biologist and Emily Heaton (now with Department of Crop Sciences at University of Illinois). Survey findings informed future education and outreach activities, including two infographic-style fact sheets, produced as part of this project.

(Objective 3) Because no fall seeding was possible in 2019, the spring of 2020 was used to seed the perennial CP23 mix. This was completed for all four sites by the end of May 2020. Soil nitrate samples were collected from June through October of 2020 and April through October of 2021 from the perennial seeded area plus the adjacent row crop area. For nearly all sampling periods and locations, soil nitrate values were lower where the perennial mix was planted. Interestingly, at several locations in both years, soil samples were not able to be collected from the adjacent row crop field due to drought conditions in July and/or August; however soil samples were possible in the perennial seeded area. As expected, the soil nitrate concentration difference with corn was much greater than with soybean. This can be associated with nitrogen applications needed for optimal corn production. Soil health assessment samples were taken from the converted perennial planting and paired row crop field area in July and September of 2021; however, only September samples were analyzed because sample quality was poor at many locations due to extreme drought conditions. At the newly established perennial vegetation sites, no vegetation assessment was conducted in 2020 (1st year of establishment) because establishment management and slow establishment of perennial species did not allow for accurate assessments to be made. Vegetation assessments were conducted on these sites in 2021. This vegetation assessment determined percent bare soil, annual grasses, perennial grasses, annual forbs, and perennial forbs. By most accounts the annual grasses and forbs are considered weedy species in Iowa. The perennial grasses and forbs were the desirable species expected with the perennial seeding. Soil nitrate and vegetation assessment findings informed future education and outreach activities, including incorporation into the Redefining the Field Edge conservation case studies produced as part of this project.

(Objective 4) Three perennial planting-focused Rapid Needs Assessment and Response (RNR) workshops were held in 2019 specifically focused on assessing attitude shifts towards diversification of our landscapes, participants’ understanding of the science and their willingness to promote specific conservation practices. The first half hour of the workshop served as the rapid needs assessment, utilizing the carousel brainstorming technique, and the remaining hour and a half focused on addressing concerns and questions that were raised during the first part. These perennial plantings RNR workshops helped team members more accurately measure attitudes, perceptions and needs of individuals across the state to better inform our programming. If we hope to increase perennial plantings in Iowa, here are the two biggest takeaway messages from the workshops: 1) More knowledge is needed including where to plant, how to plant, and impacts on environment, and 2) More assistance is needed, both labor and financial. In addition, pre-(November-December 2019), mid- (July-August 2020), and post-assessment (February-March 2022) interviews were completed with the 4 farmers to assess their attitudes, perceptions, and changes in understanding over the course of the project. Workshop and interview findings informed future education and outreach activities, including two infographic-style fact sheets, produced as part of this project.

Research conclusions:

Perennial native mix species are very slow to establish. They can be sensitive to weather conditions and establishment management (e.g. mowing 2-3 times at a height of 6 inches is really important). Additionally, farmers have very little experience with seeding native mixes that are very small and many of these areas are small areas which make use of traditional row crop equipment very difficult.

However, converting profit-loss areas of crop fields into perennial vegetation yielded a wide range of positive outcomes among soil, plants, and wildlife species of conservation concern even in the first 2 years of establishment. Specifically, the project team found:

  • Significantly lower soil nitrate concentrations in the perennial vegetation areas compared to similar row crop soils.
  • A wide diversity of birds, including many in long-term declines in the state, using these parcels during the breeding season.
  • Evidence of monarch reproduction and resources to support larval young and foraging adults.
  • Nectar resources were available in each previously-established perennial vegetation field, though not uniformly, and deficient early in the summer when some insects need them.
  • Milkweed sources for monarch nursery plants were common in the parcels, though variable among fields due to original seed mixes or post-establishment maintenance.
  • Annual plants can dominate in these areas where floods are flashy and constrain establishment of perennials. Setting realistic expectations for plant communities and buffering most flood prone areas with dryer ground with more establishment success is likely necessary.
Participation Summary
7 Farmers participating in research

Project Activities

Perennial vegetation survey instrument

Educational & Outreach Activities

10 Consultations
4 On-farm demonstrations
2 Published press articles, newsletters
2 Webinars / talks / presentations
4 Workshop field days
7 Other educational activities: 3 Rapid Needs Assessment and Response workshops, 3 field tours, 1 teacher workshop

Participation Summary:

281 Farmers participated
235 Ag professionals participated
Education/outreach description:

Rapid Needs Assessment and Response workshops were conducted on 6/13/2019 (Smeltzer Farm, Otho, IA; 27 attendees), 6/18/2019 (Spirit Lake, IA; 36 attendees), and 7/9/2019 (Whiterock Conservancy, Coon Rapids, IA; 26 attendees).

Early-assessment interviews were conducted by J. Benning, M. Licht, and L. Ripley in November/December 2019. These interviews sought to identify farmer thoughts and interest as a low profitability field site was being identified. Participants included 7 farmers.

Webinar presented by Adam Janke on Finding Mutual Opportunities for Soil, Water, and Wildlife by Redefining the Field Edge on 4/15/2020. There were 87 live attendees.

Mid-assessment interviews were conducted by J. Benning in July and August 2020. Participants were the 4 farmer partners.

Virtual Field Day hosted by Dennis Staudt on 9/10/2020. There were 52 live attendees.

Case studies were completed and already updated in 12/2021 to include two seasons of field data on soil nitrate assessments and one season of vegetation assessments. Teacher PowerPoint, agenda, and alignment with Iowa Core Standards have been added and are included in the Educator Resources folder of the Conservation Case Study Training Kits.

Wallaces Farmer: Redefine field edge in farm management – 12/15/2021

Virtual Field Day hosted by Field Extension Education Laboratory on 2/3/2022. There were 80 live attendees.

Webinar presented by Mark Licht on Redefining the Field Edge Case Study on 2/16/2022. There were 70 live attendees.

Successful Farming: Reimagine Profit-Loss Areas in Your Fields – 2/4/2022

Post-assessment interviews were conducted by L. Ripley in February and March 2022. Participants were the 4 farmer partners.

Middle school and high school teachers were introduced to the case studies in a workshop conducted in partnership with Science Bound on 4/23/2022. The workshop had 11 teacher participants.

In-person field day was hosted at Brent Johnson’s demonstration site on 6/1/2022. There were 23 attendees.

Field tour for K-12 teachers on 6/16/2022 showcased low-profitability area of field seeded to perennial vegetation. There were 16 attendees.

Field tour for K-12 teachers on 6/23/2022 showcased low-profitability area of field seeded to perennial vegetation. There were 10 attendees.

In-person field day was hosted at Mark Kenney’s demonstration site on 8/24/2022. There were 28 attendees.

Field tour on 9/2/2022 showcased low-profitability area of field seeded to perennial vegetation, as part of International Drainage Symposium. There were 35 attendees.

Two infographic-style fact sheets were completed outlining the findings of the project, from site selection to best management practices for the newly redefined field edge and successful establishment of perennial vegetation.

Learning Outcomes

116 Farmers reported changes in knowledge, attitudes, skills and/or awareness as a result of their participation
160 Agricultural service providers reported changes in knowledge, skills, and/or attitudes as a result of their participation
Key areas taught:
  • Benefits of transitioning unprofitable field areas to perennial vegetation, including benefits to water quality, soil erosion, wildlife, and overall farm profitability.

Project Outcomes

20 Farmers changed or adopted a practice
Key practices changed:
  • No-till/strip-till, cover crops, pollinator habitat

2 Grants applied for that built upon this project
6 New working collaborations

Information Products

Any opinions, findings, conclusions, or recommendations expressed in this publication are those of the author(s) and do not necessarily reflect the view of the U.S. Department of Agriculture or SARE.