Producer Education of Nitrate Reduction Strategies and Evaluation of Acceptance

Final Report for GNC09-103

Project Type: Graduate Student
Funds awarded in 2009: $9,953.00
Projected End Date: 12/31/2011
Grant Recipient: Iowa State University
Region: North Central
State: Iowa
Graduate Student:
Faculty Advisor:
Dr. Matthew Helmers
Iowa State University
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Project Information


Decreased water quality due primarily to nitrate loadings from agricultural drainage has plagued the US Midwest for the past several decades. There are a variety of on-farm nitrate reduction technologies that can be employed to reduce this problem, but implementation may be limited by education of the available options. The outcomes of this work were (1) to provide producers increased understanding of nitrate reduction technologies and (2) to provide researchers increased knowledge of levels of acceptance of various nitrate reduction approaches so as to better focus educational approaches. The foundation of this work was a comparison of economic cost efficiencies and ecosystem services provided by seven nitrate reduction methods (wetlands, controlled drainage, cover crops, crop rotation, fertilizer rate reduction, fertilizer timing modification, and denitrification bioreactors). These comparisons were used to develop and inform an educational program with an associated survey evaluation and a supplementary farmer discussion group. The educational program providing financial cost/benefit and ecosystem service information of the seven approaches was given at five Iowa Learning Farm Field Days during summer 2011. Following the events, the producers in attendance had the opportunity to answer mailed survey questions about their background, their understanding of the technologies and their interest in implementing one or a combination. The survey was also mailed to participants of four field events where the education program was not presented in order to obtain control data providing a baseline on producer acceptance of these technologies. To further study the perceived adoption potential of these practices in the context of ecosystem service provisioning, a small discussion group was held with farmers.

Each N reduction strategy provides landowners an additional distinct option for drainage water quality improvement and different strategies or combinations of such will be applicable in different locations. While the N management practices were very cost effective and had high interest and compatibility, they offered few additional ecosystem services. Conversely, the practices that had high ecosystem service provisioning generally had lower compatibility (wetlands) or interest (crop rotation). A notable exception was cover crops which, although more expensive per unit nitrate treated, had high compatibility, interest and ecosystem services.


Nitrate from agricultural sources, primarily tile drainage in the Midwest, has been identified as a major source of nitrate loadings in the Mississippi River. These loadings are a key cause of water quality impairment in the Gulf of Mexico with this resulting hypoxic zone larger than average in 2011. The time is right for increased implementation of nitrate reduction strategies for agricultural sources in the Midwest to lead to increased sustainability of such agricultural systems.

Numerous nitrate reduction methods are currently under investigation to examine effectiveness in varying agricultural systems. These strategies include wetlands, controlled drainage, cover crops, crop rotation, and nutrient management. Denitrification bioreactors are the newest addition to this slate of nitrate reduction technologies. From the producer perspective, each of these nitrate reduction strategies has associated advantages/ disadvantages. While each approach can be valuable, the effectiveness will be site specific and the acceptability of each individual approach will differ between producers based on varying ecosystem services and economic benefits of the approach. A comparison of the economic value of and the ecosystems services offered by each of these methods would be valuable to producers and landowners interested in nitrate reduction.

The foundation of this work was a comparison of economic cost efficiencies and ecosystem services provided by seven nitrate reduction methods (wetlands, controlled drainage, cover crops, crop rotation, fertilizer rate reduction, fertilizer timing modification, and denitrification bioreactors). These comparisons were used to develop an educational program with an associated survey to gage the social acceptance of these seven nitrate reduction methods. To further study the perceived adoption potential of these practices in the context of ecosystem service provisioning, a small discussion group was held with farmers.

Project Objectives:

The goal of this work was to provide producers increased understanding of nitrate reduction technologies and to provide researchers enhanced knowledge of producer acceptance of various nitrate reduction approaches so as to better focus research and education. As of submission of this Final Report, all major Performance Target tasks, barring submission/acceptance of results for peer-reviewed publication, had been performed. This project’s Performance Targets included:

• Perform an economic analysis to develop cost efficiencies for seven drainage water quality improvement technologies (wetlands, controlled drainage, cover crops, crop rotation, fertilizer rate reduction, fertilizer timing modification, and denitrification bioreactors)
• Create an educational program focused on this economic comparison
• Present this program at five field events with a post-event survey mailed to participants afterwards (plus survey mailed to a control group)
• Convene a discussion group with farmers to further explore the perception of ecosystem services associated with these seven drainage water quality practices
• Analyze survey and discussion group data
• Create a university extension factsheet focused on the newest of the technologies, denitrification bioreactors
• Incorporate results into the Project Director’s Ph.D. dissertation and into peer-reviewed journal publications

Consistent with the proposal and 2010 Annual Report, a short term outcome is increased knowledge of costs and benefits of various nitrate reduction strategies, including the new technology of denitrification bioreactors, for producers, land owners, and contractors. Additionally, on a more basic level, these programming efforts will also increase producer understanding that there is a nitrate water quality problem associated with agricultural drainage.

Intermediate outcomes include assessment of factors limiting implementation of nitrate reduction strategies allowing more focused research and education efforts pertaining to drainage water quality. It is thought this assessment will be informed by the producers’ survey results. Moreover, these survey results will bring about increased understanding of the effectiveness of the educational efforts. Other intermediate outputs include results being incorporated into the Project Director’s Ph.D. dissertation and into peer-reviewed journal publications.

A projected long term outcome (systemic change) is the potential for increased adoption of nitrate reduction methods by Midwestern farmers leading to decreased transport of nitrate to the Mississippi River and Gulf of Mexico. However, evaluation of actual adoption of these technologies was beyond the scope of the work here and is recommended for future work.


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  • Dr. Matt Helmers


Materials and methods:

Economic Analysis
Capital budgeting procedures were used to develop cost efficiencies for each of the seven practices. The total present values of the costs for each practice were converted to Equal Annual Costs (EAC) using a capital recovery factor. This method of EAC development was the most appropriate approach as we were comparing investments which varied in life span, financial terms, and maintenance costs. By annualizing all costs, the EAC allows landowners or policy makers to examine costs of these practices more easily across a longer time-scale. For each practice, available published cost information was used to develop a farm-level financial model (resulting in the EACs for each practice) that assessed establishment and maintenance/replacement costs as well as examined financial effects of potential yield impacts over a 50 yr timeframe. Then, each practice’s cost values were combined with literature review of N reduction, which allowed comparison of these seven practices in terms of cost effectiveness (EAC dollars per kg N removed).

Ecosystem Service Analysis
The framework for this qualitative comparison of ecosystem services provided by the seven technologies was based upon the three categories of ecosystem services defined by the Millennium Ecosystem Assessment: provisioning, regulating, and cultural. Based on a review of literature and on professional opinion, each practice was given a +1, a 0, or a -1 for an increase, no change, or decrease, respectively, in a given service. These values were then summed across the three service categories and across the seven practices.

Extension programming and farmer survey
The cost efficiencies of the seven water quality technologies (above) were used to create an outreach presentation given at five Iowa Learning Farms field events during summer 2011. An integral part of the program was the dissemination of a cost efficiency hand-out describing the seven practices. Two weeks after each event, the attendees received a mailed survey designed to identify their background, their understanding of the nitrate reduction technologies and their interest in or barriers for the technologies. To provide baseline “control” information, the survey was also sent to attendees of four Iowa Learning Farms field events during summer 2011 where the water quality educational program had not been delivered.

Small Discussion Group
To more fully develop the ecosystem service component of the proposal, a group discussion with eleven farmers from central Iowa was conducted on 13 September 2011. The event began with a brief presentation detailing the technical aspects of the seven water quality practices; however, the cost information developed for the field events was not shown. The participants then undertook an individual written activity to provide information on their individual perceptions of the limitations and on-farm and regional benefits of each practice. Following this, the participants split into two small groups and the discussion facilitators initiated dialogue by posing the open-ended question: What are the benefits and limitations of using each of the seven practices that are experienced by both farmers and society? The discussions were recorded on large pads of paper and using digital voice recorders. During qualitative analysis of this data, open-coding from notes and the large paper pads were used in theme development with the recordings used to provide context.

Research results and discussion:

All the outlined performance targets were met except for final submission and acceptance of the study information in peer-reviewed journals. In context of both the economic analysis and the social perception studies (i.e., survey and discussion group results), the two N management strategies seemed to be “low-hanging fruit” for nitrate mitigation in drainage water. These two practices (i.e., rate reduction and application timing modification) were the most cost effective and also were some of the highest ranked in terms of interest among producers based on survey and discussion group results. Unfortunately, these practices provided few additional ecosystem services.

Cover cropping and diversified crop rotations were the most expensive based on the economic analysis but also provided the most ecosystem services (along with wetlands). For cover crops, this high ecosystem service count matched well with the comparably high value of “stacked benefits” perceived by producers. Importantly, this practice also ranked highly in compatibility with existing management goals and outranked all other practices in terms of producer interest. On the other hand, the high number of ecosystem services for the crop rotation practice was not reflected by the low “stacked benefits” perceived by the discussion group farmers. This disconnect potentially exemplifies the need for more information about this practice. Moreover, the crop rotation strategy ranked second lowest among practices in which water program attendees had interest (bioreactors elicited lowest interest).

Participation Summary

Educational & Outreach Activities

Participation Summary

Education/outreach description:

Several outreach events were a part of this work:
• The educational program was given at five Iowa Learning Farms (extension-related) field events around the state of Iowa during summer 2011.
• A supplementary discussion group (i.e. a small focus group) with farmers was held on 13 September 2011 to gain a better understanding of benefits beyond water quality that were perceived to be associated with these seven water quality technologies. Discussions at this event were focused on ecosystem services in the context of “on-farm” and “regional” benefits offered by the technologies.

Three major publications resulted from or are pending from this work:
• A University Extension Factsheet entitled “Woodchip Bioreactors for Nitrate in Agricultural Drainage” was officially released in November 2011. Publicity about this factsheet is available at: and at It was possible to make this “expert-reviewed” factsheet available as a free downloadable PDF through this SARE funding and complementary funding from the Leopold Center for Sustainable Agriculture. Notably, the illustration developed for this factsheet has been requested to be used in other informational materials (handouts, presentations, technical reports) by out-of-state researchers and government officials, thus widening the audience for this work.
• The economic comparison, “Financial Comparison of Seven Nitrate Reduction Strategies for Midwestern Agricultural Drainage”, was included as a chapter in the Project Director’s Ph.D. dissertation. This paper is currently undergoing revision for submission as a peer-reviewed journal article. This work has received favorable acknowledgement from colleagues for being a novel approach for economically comparing water quality practices in an “apples to apples” manner. See above “Economic Analysis” section for more information.
• The producer survey results from the educational program combined with information from the farmer discussion group allowed creation of a paper tentatively entitled “An ecosystem services approach to farmer adoption potential of drainage water quality improvement strategies”. It is anticipated this paper will be submitted for peer-review in early summer 2012. See below “Farmer Adoption” section for more information.

Project Outcomes

Project outcomes:

Economic Analysis

The economic analysis allowed development of cost efficiencies for the seven drainage water quality practices upon which the programming efforts were based. It was calculated the N management practices of reduced application rate and moving application from the fall to the spring were the most cost effective. However, it’s important to note the scenarios here were limited in scope (e.g., only investigated reducing application rate from 168 to 140 kg N/ha as these rates were generally accepted as within the range of common practice), and the evaluation of other N management strategies and associated assumptions could yield different results. The least cost effective practices were the in-field vegetative practices of a winter rye cover crop and a crop rotation including three years of alfalfa. With this economic analysis’s exclusive focus on drainage water nitrate mitigation, these practices that provided significant additional ecosystem services received no extra monetary credit for benefits such as enhanced soil productivity or erosion protection. The three engineering-based practices of controlled drainage, bioreactors and constructed wetlands had comparable cost efficiencies prior to inclusion of governmental cost-share programs; wetlands were very cost effective when government incentives (i.e., CREP payments) were included. This economic assessment made clear it was necessary to further investigate these practices in regards to ecosystem service provisioning to more fully evaluate attributes that could be important for adoption by farmers.

Farmer Adoption

The water quality program survey evaluation results indicated the programming influenced the level of interest associated with several of the practices. For example, the percentage of respondents who were interested in controlled drainage increased from 15% to over 30% when comparing the population who did not attend the water quality program vs. population present at the program, respectively. The survey results also showed that installation and equipment costs were the most predominant barrier to adoption of these practices (59% of all respondents). Other notable barriers were the need for increased information, maintenance costs, and additional time required at 40, 32, and 27%, respectively. This adoption theme was investigated further during the discussion group. Based on the analysis of commonly voiced themes, the N management and cover cropping practices provided comparably high multi-scale relative advantages or “stacked benefits” as well as the highest compatibility with farming goals.

During the discussion group, there were dissatisfactions with the current cost-share programs’ inflexibility and their limitations. However, from the survey data, it was clear that monetary incentives were required for water quality improvement practice adoption. Monetary incentives and educational programs were the two most frequently selected options by survey participants when asked to indicate what was needed to increase adoption (each was checked by 44% of the combined survey populations). This correlated well with the barriers of installation/equipment costs and a desire for increased information mentioned above.


Areas needing additional study

As mentioned above, the evaluation of actual adoption of these seven practices was beyond the scope of this study. Because levels of interest (as quantified here) can significantly vary from actual adoption rates, further work could be done to investigate concrete adoption of drainage water quality practices. Also, the discussion group participants indicated there was a need for more demonstration sites and events so farmers could see some of these conservation practices in place. This was consistent with the second place ranking on the survey for “more information needed” as a barrier to implementation of these technologies.

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.