Category: Environmental Planning

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Changes in amount and location of US dairy manure production from 1970-2023

Purpose

We estimated milking cow manure production for US states from 1970 to 2023 with the aim to provide a broad perspective to stakeholders who manage and optimize the use of dairy manure. Stakeholders include producers and those working on their behalf such as agronomists, applicators, engineers, extension agents, researchers, governmental agencies, cooperatives, and markets.

It is hoped that with increased understanding of how manure production has changed over time and location stakeholders can better understand trends and historical conditions which impact their efforts.

What Did We Do?

We estimated milking cow manure production for 48 US states from 1970 to 2023 using an empirical equation estimating manure production as a function of milk production published by the American Society of Agricultural and Biological Engineer’s Manure Production and Characteristics standard. To apply this equation to each state we utilized two data sources produced by the United States Department of Agriculture’s National Agricultural Statistics Service (NASS), annual milk production and annual milking cow herd size. To gain further insight data sources reporting the number of dairy farms and land available for manure application in each state were additionally gathered from NASS and reported in combination with manure production. The workflow and references for combining this data are displayed in the following figures.

Figure 1. Workflow to estimate annual dairy manure production using ASABE’s Manure Production and Characteristics standard and NASS milk cow production and cow herd inventory data sources.
Figure 1. Workflow to estimate annual dairy manure production using ASABE’s Manure Production and Characteristics standard and NASS milk cow production and cow herd inventory data sources.
Figure 2. Workflow to estimate number of dairies and acres for manure application from NASS data sources.
Figure 2. Workflow to estimate number of dairies and acres for manure application from NASS data sources.

What Have We Learned?

Nationally annual dairy manure production has decreased from 1970-2023 by approximately 4% (2.2 billion gallons). From 1998 to 2023 annual dairy manure production increased by approximately 13% (6.4 billion gallons). Although national milking cow numbers generally declined from 1970 to 1998 then nearly remained constant until 2023, this trend was offset by continual increase in manure production per cow from 1970-2023 due to the direct relationship with milk production, which has continued to increase from 1970-2023. Also, the annual number of gallons of manure per dairy farm has increased from 1970-2023 due to a decrease in number of dairies combined with an increase in manure production per cow. It is accepted that the US dairy industry has consolidated over time, this data supports that its’ manure production has consolidated as well.  The author posits based on experience and this analysis that nationally, over time, manure systems in support of livestock production have contributed to an increase in volume of manure being managed to date. As dairy cows move to increasing levels of confinement, from pasture and lots which utilize land base as a manure system to barns with more engineered manure systems, greater collection of manure occurs and therefore must be managed. Regarding the impact of the specific type of engineered manure systems impact on volume of manure that must be managed the author posits this currently varies based on the kind of manure system selected, either adding or subtracting to the managed manure stream, which is a function heavily dependent on local climate (precipitation, evaporation, and length of storage period) and technology adoption (covers, flush systems, separation, and advanced treatment). In the upper Midwest with relatively high precipitation, low evaporation, and long winter periods dairy manure systems are predominantly collect and store only, overall adding to the volume of manure to be managed as additional precipitation is also captured by the uncovered nature of most storages in this region.

Figure 3. National change in manure and milk production, milking cow inventory, and number of dairies from 1970 to 2023.
Figure 3. National change in manure and milk production, milking cow inventory, and number of dairies from 1970 to 2023.

At the state level the change in manure production has varied. From 1970 to 2023, 12 states have increased manure production, the remaining 26 states have decreased manure production. This has resulted in a change in the location of where manure is produced. In 2023, most manure was produced in a few states. In 2023, 10 states produced 70% of the total annual US dairy manure production, with 6 states producing over 50%.

Figure 4. 2023 annual milking cow manure production, millions of gallons, and percent change of annual milking cow manure production from 1970 to 2023.
Figure 4. 2023 annual milking cow manure production, millions of gallons, and percent change of annual milking cow manure production from 1970 to 2023.

Future Plans

Authors seek to maintain this data analysis in a method available to stakeholders, additionally incorporating manure production from swine, beef, and poultry into it, and updating it as future NASS reports are published.

Authors

Presenting & corresponding author

Mike Krcmarik, Professional Engineer, mikekrcmarik@gmail.com

Additional Information

Email corresponding author for copy of all data and figures used in this analysis, including figures published on the poster only.

Acknowledgements

    • American Society of Agricultural and Biological Engineers, Engineering Practices Subcommittee of the ASAE Agricultural Sanitation and Waste Management Committee responsible for standard ASAE D384.2 Manure Production and Characteristics used in this analysis.
    • United States Department of Agriculture’s National Agricultural Statistics Service responsible for the various surveys and reports used in this analysis.
    • Allen Young, Eric County Soil and Water Conservation District (New York) providing valuable review and discussion.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2025. Title of presentation. Waste to Worth. Boise, ID. April 7–11, 2025. URL of this page. Accessed on: today’s date.

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Effective community co-creation approaches for livestock manure management

Due to a technical glitch, we did not get this presentation recorded. Please accept our apologies.

Purpose

Climate solutions are often talked about in a vacuum and conversation participants can sometimes overlook unintended consequences upon local environment and health. Solutions to mitigate methane from livestock agriculture are no exception to these climate discussions, and can impact other potential pollutants including ammonia, nitrous oxide, and odors. Moreover, it can be a particularly difficult space to work in climate and environmental justice, as many different communities are seemingly villainized and pit against each other, which make climate solutions even harder to implement.

What Did We Do?

Environmental Defense Fund is in the midst of an ongoing pilot project to engage communities in workshops around solutions regarding manure management. The goal of these workshops is to demonstrate best practices for effective collaboration and solution co-creation between farmers/producers and communities that can then be taken to local policymakers and stakeholders to implement. In this way, we can co-create solutions that align with community concerns, climate change mitigation, and feasibility for farmers.

What Have We Learned?

Community co-creation is possible, and even stakeholders who may seem hyper-polarized can still sit together at the same table to work together with ample time, transparency, and trust. Policy implications are enormous here and this session will discuss learnings we have regarding common misconceptions and myths around working with different affected stakeholders, as well as necessary guardrails surrounding commonly discussed methane mitigation technologies.

Future Plans

We will continue to work with the affected communities, including community groups and producer groups, to find common ground, with the hope of making these processes shareable across the country.

Authors

Presenting & corresponding author

Mindi W. DePaola; Senior Manager, Community and Equity, Ag Methane; Environmental Defense Fund, mdepaola@edf.org

Acknowledgements

We’d like to thank groups who have continued to give us time, as time is the biggest resource. These groups include White Earth Nation, EJCAN, Leadership Counsel for Environmental Justice, and MN Milk. NOTE: these are not necessarily official partners but again, want to acknowledge their time spent meeting with EDF.

 

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2025. Title of presentation. Waste to Worth. Boise, ID. April 7–11, 2025. URL of this page. Accessed on: today’s date.

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The Economics of Carbon Markets for Dairy Industry

Purpose

Dairy farmers in Washington state have been under significant pressure to reduce their carbon footprint in recent years. Dairy cooperative sustainability initiatives such as achieving carbon neutrality by 2050 have left many producers wondering what will be required of them to help their cooperatives meet this goal. Coupled with regulatory pressures to report on their greenhouse gas emissions and the threat of regulation to reduce them, uncertainty remains for producers around the types of climate-smart practices that will enable them to reduce their carbon footprint while remaining economically viable.

Without a thorough understanding of the costs and risks, pressures, or requirements to implement climate-smart practices may inadvertently drive consolidation and the accelerated loss of small to medium sized farms.

What Did We Do?

Utilizing Washington state dairy facility data, I conducted an economic cost benefit analysis of two climate-smart practices that capture GHGs from anaerobic storage: anaerobic digestors and the covered lagoon and flare system and the size of operation needed to implement both practices based on current and historic market conditions and technology costs. Private and public investment in climate-smart practices can have a substantial impact on whether they are economically feasible for producers to implement. I considered the impacts of various levels of cost-share on the size of farm able to adopt the technology based on several economic indicators.

What Have We Learned?

Most dairy farms cannot simply raise their prices to offset the costs of climate-smart practices, therefore it is critical to understand the broad economic impacts of imposing emissions reductions mandates. With consolidation being a well-documented trend across dairy farms in the United States, it is possible that climate regulations will only further exacerbate this trend due to the high capital costs and market risk associated with climate-smart farming that only facilities of scale can take on.

Future Plans

I am actively assisting research right now in Washington state with university and private researchers into dairy farm carbon intensities, across various farm sizes and facility types. An overview of this research may be available by Summer of 2025. Once this work is completed, we will have a better understanding of overall farm emissions and what climate-smart practices may be necessary for farms to implement to help achieve cooperative net zero targets.

Authors

Presenting & corresponding author

Nina Gibson, Agricultural Economist and Policy Specialist, Washington State Department of Agriculture, KGibson@agr.wa.gov

Additional Information

Link to Podcast I hosted, the Carbon and Cow$ Podcast, which covers the risks and opportunities associated with carbon markets for dairy and livestock producers: https://csanr.wsu.edu/program-areas/climate-friendly-farming/carbon-and-cows-podcast/

Link to my program’s homepage at WSDA: https://agr.wa.gov/manure

My Linkedin: https://www.linkedin.com/in/nina-gibson-b482a8119/

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2025. Title of presentation. Waste to Worth. Boise, ID. April 7–11, 2025. URL of this page. Accessed on: today’s date.

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Enhancing Precision Manure Nutrient Application with Near-Infrared Spectroscopy (NIRS) Sensors

Purpose

Land application of manure is crucial for providing nutrients to crops, yet challenges such as nutrient losses and reduced nutrient use efficiency (NUE) affect sustainability. This study evaluates a commercially available real-time near-infrared spectroscopy (NIRS) nutrient-sensing system to enhance precision manure nutrient application in crop production systems. The study assesses the impact of the NIRS system on manure application rates, NUE, and crop yield compared to conventional fixed-rate methods.

What Did We Do?

Field trials were conducted using a John Deere Harvest Lab 3000 NIRS system, rate controller, and Krone Flow meter on a manure tanker, Figure 1. Manure was applied to achieve a target total nitrogen rate for corn silage, with application rates varied to simulate manure nutrient variations during lagoon emptying.

Figure 1. Location of sensor on manure tanker
Figure 1. Location of sensor on manure tanker

What Have We Learned?

Although NIRS predictions taken in laboratory conditions for total nitrogen were lower than the ranges reported for Manure analysis proficiency (MAP) certified laboratory results, the ammoniacal nitrogen,  phosphorous (P2O5), and potassium (K2O) were with the MAP lab ranges reported in Sanford et al. (2020). However, additional data is needed for assessment of the sensor accuracy during field conditions.

First-year field trial data indicate that NIRS was closer to the intended nitrogen application rates and had improved NUE with no significant differences in yield compared to those using conventional fixed-rate application methods. Further, the system is capable of producing manure nutrient application maps that can be used for supplemental nutrient applications, Figure 2.

Figure 2: Nitrogen application maps produced by the sensing system during plot trials
Figure 2: Nitrogen application maps produced by the sensing system during plot trials

Overall, integrating NIRS into the land application system demonstrates potential improvements in precision nutrient application over conventional methods. Further trials and analyses are planned to assess the accuracy of the NIRS sensor and its broader impact on nutrient management and application precision.

Future Plans

Researchers plan to continue field trials for another one to two years to assess the impacts over multiple field years. This includes assessing the sensor accuracy in field conditions. Further, researchers’ previous trials have focused on applying based on manure nitrogen content. Additional trials will assess applying manure with a phosphorus limit using the same sensor. Lastly, researchers are working to guide farmers interested in integrating the system and aiding in using developed maps to improve supplemental nitrogen application.

References

Sanford, J.R., R.A. Larson, & M.F. Digman. 2020. Assessing certified manure analysis laboratory accuracy and variability. Applied Engineering in Agriculture, 36(6):905-912. https://doi.org/10.13031/aea.14214

Authors

Presenting author

Tyler Liskow, Engineer, Professor, Nelson Institute for Environmental Studies, University of Wisconsin-Madison

Corresponding author

Rebecca A. Larson, Professor, Nelson Institute for Environmental Studies, University of Wisconsin-Madison, rebecca.larson@wisc.edu

Additional authors

Tyler Liskow, Engineer, Nelson Institute for Environmental Studies, University of Wisconsin-Madison; and Joseph Sanford, Assistant Professor, University of Wisconsin-Platteville

Acknowledgements

This material is based on work that is supported by the National Institute of Food and Agriculture, U.S. Department of Agriculture under award number 2022-69008-36506.

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.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2025. Title of presentation. Waste to Worth. Boise, ID. April 7–11, 2025. URL of this page. Accessed on: today’s date.

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The Effect of Cover Crops on Nutrient Leaching

Purpose

An NRCS Conservation Innovation Grant (CIG) state-wide study examining soil health is underway.  Seventeen farms across the state of Utah are incorporating various soil health practices and are comparing them to their conventional practices (no soil health treatment).  Mini zero-tension lysimeters (12” diameter) were installed at two of the locations in northern Utah (Cache Valley), to collect leachate.  Cache Valley has a semi-arid climate with warm summers and cold winters.  The soil type on both farms is a Lewiston sandy loam.  Both of these farms apply manure and are incorporating cover crops as part of their soil health management.  The fields are irrigated.  Leachate is being collected to evaluate the impact of cover crops on nutrient leaching.  Other scientists are examining various soil health parameters, such as bulk density, soil carbon tests, water infiltration, etc.

Leachate is being collected bi-weekly throughout the growing season, and as late as possible into the winter.  Leachate samples are being analyzed for available N (ammonia and nitrate/nitrite), and dissolved phosphorus on a Lachat Auto-Analyzer using Methods 10-10701-2-A, 10-107-04-1-A, and 10-115-01-1-A, respectively.  Deep soil cores are also being collected to a depth of 5 feet and will be analyzed for nitrogen and phosphorus.

What Did We Do?

Mini zero-tension lysimeters were installed in the spring of 2023.  In year 1, both farms (GS and JC) planted corn with a cover crop (rye, clover, vetch, brassica mix) being interseeded at ~ the V5 stage.  Due to the short growing season, cover crop establishment early in the season, before canopy cover, is needed to get adequate cover crop growth in the fall.  In year 2, the GS Farm began transitioning to alfalfa.  Oats were planted in the spring and terminated for a late summer/early fall alfalfa planting.  Three-way grass will be interseeded into alfalfa in the spring of 2025 for the soil health treatment.  In year 2, the JC Farm missed the window for getting the cover crop interseeded into the corn crop.  There was no soil health treatment in effect for the 2024 growing season on the JC Farm.

Leachate is being collected bi-weekly throughout the growing season, and as late as possible in the winter.  Leachate samples are being analyzed for available N (ammonia and nitrate/nitrite), and dissolved phosphorus on a Lachat Auto-Analyzer using Methods 10-10701-2-A, 10-107-04-1-A, and 10-115-01-1-A, respectively.  Deep soil cores are also being collected to a depth of 5 feet and will be analyzed for nitrogen and phosphorus.

What Have We Learned?

On the GS Farm, the leachate from the soil health treatment had, on average, a lower nitrate concentration.  There was also less leachate produced, and less total nitrate going past the soil root zone.   On the JC Farm in 2023, the soil health treatment also produced leachate with a lower nitrate concentration than their conventional treatment.  There was also less total leachate produced and less total nitrate loss when cover crops were interseeded into the corn in 2023.  Those results disappeared in 2024 when a cover crop was not planted.  Even with the cover crop, the leachate (on average) exceeded the drinking water standard for nitrate concentration.  The application of manure in the spring likely contributed to this loss.

Future Plans

This study will continue for three more years.  The goal is to verify and demonstrate practices that improve soil health and minimize environmental impacts.

Authors

Presenting & Corresponding author

Rhonda Miller, Professor, Utah State University, rhonda.miller@usu.edu

Additional authors

Katie Hewitt, Graduate Student, Utah State University; Bruce Miller, Professor, Utah State University

Acknowledgements

Funding provided by NRCS CIG Grant “Utah Soil Health Partnership On-Farm Trials” – Agreement Number NR223A750013G009

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2025. Title of presentation. Waste to Worth. Boise, ID. April 7-11, 2025. URL of this page. Accessed on: today’s date.

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Using ManureTech Decision-Support Tools to Aid in Manure System Selection

Purpose

The purpose of the ManureTech Decision-Support Tools (DST) for Dairy and for Swine is to assist farmers, consultants, and others in the dairy/swine industry in optimizing the management of manure from collection to land application. By providing data-driven recommendations based upon customizable inputs and priorities, the ManureTech DST help users make informed decisions about manure management systems in consideration of the economic, environmental, and operational needs of farm management.

What Did We Do?

A multi-state team has developed Excel-based decision-support tools for selecting technology and systems for managing manure on dairy and swine operations as part of a USDA NIFA-funded project.

During this workshop, participants will be introduced to the ManureTech DST for Dairy and the ManureTech DST for Swine and will be provided with hands-on training in using the decision-support tool for dairy.  Major aspects of the tools that will be addressed in the workshop include an introduction to the user interface; entering primary inputs; prioritization of economic, environmental, and operational metrics; and reporting of results, including the ranking of manure system scenarios.

What Have We Learned?

In terms of learning, this effort has provided the project team with a fuller grasp of the complex nature of manure management!  In terms of accomplishments, the team has assembled a tool that considers the multi-faceted benefits and challenges of various manure management systems and presents users with a ranked list of systems for consideration, which should help expedite and enhance system selection.  Users of the ManureTech DST can provide farm-specific weight to economic, environmental, and operational criteria which allows ManureTech DST to rank alternative manure management scenarios in close alignment with individual priorities.

This visual illustrates what a user of the ManureTech Decision-Support Tool sees when weighing economic, environmental, and operational priorities of a farm, so that the rankings of the manure management systems reflect these farm priorities.  In the illustrated case, the user preferences favor economic priorities over others.
This visual illustrates what a user of the ManureTech Decision-Support Tool sees when weighing economic, environmental, and operational priorities of a farm, so that the rankings of the manure management systems reflect these farm priorities.  In the illustrated case, the user preferences favor economic priorities over others.

Future Plans

Future plans include completing beta testing / pilot-testing of the ManureTech DST and conducting additional training on using the tool.  Over a longer-range timeframe, the team would like to add some additional specialized capabilities and functionality, as a phase II effort.

Authors

Presenting authors

    • Erin Scott, Project/Program Manager, University of Arkansas
    • Varma Vempalli, Wastewater Treatment Specialist, City of Meridian (ID)
    • Jacob Hickman, Systems Analyst, University of Arkansas
    • Rick Stowell, Extension Specialist in Animal Environment, University of Nebraska-Lincoln
    • Teng Lim, Extension Professor and Engineer, University of Missouri

Corresponding author

Rick Stowell, Extension Specialist in Animal Environment, University of Nebraska-Lincoln, Richard.Stowell@unl.edu

Additional authors

    • Erin Scott, Project/Program Manager, University of Arkansas
    • Jacob Hickman, Systems Analyst, University of Arkansas
    • Jennie Popp, Associate Dean and Professor, University of Arkansas
    • Varma Vempalli, Wastewater Treatment Specialist, City of Meridian (ID)
    • Greg Thoma, Director of Agricultural Modeling and Lifecycle Assessment, Colorado State University
    • Teng Lim, Extension Professor and Engineer, University of Missouri

Additional Information

The ManureTech DST and related articles can be accessed at Decision-Support Tools – Livestock and Poultry Environmental Learning Community.

Acknowledgements

The authors acknowledge funding from the USDA NIFA AFRI Water for Food Production Systems program, grant #2018-68011-28691.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2025. Title of presentation. Waste to Worth. Boise, ID. April 7–11, 2025. URL of this page. Accessed on: today’s date.

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Summary of Manure Handling Certification Programs Across the United States

Purpose

Effective management of manuresheds is important to address regional mass nutrient imbalances of manure nitrogen and phosphorus (Speigal et. al., 2020). To date, a summary description of state-level certification programs of those that apply, transport, or broker manure has not been published in literature. The purpose of this research (Flynn et. al., 2025) was to: 1) enumerate and characterize manure handling certification programs across the US; 2) investigate correlation of state programs and manure surpluses/regional manureshed source areas; and 3) explore a Wisconsin case study focused on voluntary, market-based, statewide certification and correlation with reduced manure spills and safe land application.

What Did We Do?

Thorough internet examinations of state agency and university websites were used to compile descriptive data for state manure hauling, brokering, and application certification requirements. Data from a Qualtrics survey used to gather further details of certification programs received input from university or agency professionals from all 50 states. Data from the internet search and survey was compiled, quantified, and placed in a data repository (Erb, Inaoka, and Meinen, 2024). A case study summarized information from historical surveys, reports, and conference proceedings and reported impacts of certification and associated educational programming in the state of Wisconsin (e.g. Erb, 2022; Erb, 2024; Erb et. al., 2011; Erb et. al., 2021; Erb, Kostelny, et. al., 2024; Erb, et. al., 2009; Erb et. al., 2015; Erb and Stieglitz, 2007).

What Have We Learned?

Legal definitions of certification are diverse among states but can largely be defined as legal permissions to handle manure. Certification programs are present in 26 of 50 states. Certifications were placed into three categories: farmers, professional manure transporter/applicators, and manure brokers. Many states certify individuals in more than one category, that may be mandatory or voluntary. Categorization of certification programs revealed the following:

    • Producer certification existed in 21 states (15 mandatory, 6 voluntary).
    • Transporter/Applicator certification existed in 20 states (13 mandatory, 7 voluntary).
    • Broker certification existed in 10 states (7 mandatory, 3 voluntary).

When certification characterization was transferred to maps there were no clear standardization or spatial patterns between states. However, when compared to maps of animal concentrations and manureshed surplus areas, it was apparent that certification programs do cover much of the country’s intensive animal production regions. The largest lack of certification programs was in some Appalachian and western states.

Researchers concluded that state, watershed, and manureshed management goals can be assisted through certification of producers, transporters/applicators, and brokers that handle manure. Implementation of multi-state cooperation, standardization, and reciprocation of manure certification programs would assist in goals of parties across state, watershed, and manureshed boundaries.

Authors

Presenting author

Robert J. Meinen. Director Pennsylvania Nutrient Management Education Program, Department of Plant Science, The Pennsylvania State University, University Park, PA, rjm134@psu.edu

Additional author(s) (name, title, and affiliation for each)

    • Colton Flynn. USDA-ARS Grassland Soil and Water Research Laboratory, Temple, TX.
    • Kevin Erb. University of Wisconsin-Madison, Division of Extension, Green Bay, WI.
    • Jenifer L. Yost. USDA-ARS Grassland Soil and Water Research Laboratory, Temple, TX.
    • Mirai Inaoka. Department of Crop Sciences, University of Illinois at Urbana-Champaign, Urbana, IL.
    • Sheri Spiegal. USDA-ARS, Jornada Experimental Range, Las Cruces, NM.

Additional Information

Flynn, K.C., Erb, K., Meinen, R.J., Yost, J.L., Inaoka, M., and Spiegal, S. Manure Handling Certification Programs in Manuresheds Across the United States. Cleaner Waste Systems. February 27, 2025. https://doi.org/10.1016/j.clwas.2025.100241

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2025. Title of presentation. Waste to Worth. Boise, ID. April 7–11, 2025. URL of this page. Accessed on: today’s date.

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Soil Property Effect on Nitrogen Mineralization of Dairy Manure in the Pacific Northwest

Purpose

Growers often use total nitrogen (N) concentration of dairy manure to estimate plant available N for crop production. This estimate often does not take into account the role soil properties may have on N mineralization (Nmin) rates. This study aims to determine how soil properties impact Nmin rates of dairy manure and composted dairy manure by aerobic incubation. The soil properties investigated, including soil texture, percent organic matter, pH, EC, buffer pH, NO3-N, NH4-N, Olsen P, K, Ca, Mg, Na, CEC, S, Zn, Fe, Mn, Cu, B, and CaCO3 equivalent, which are all accessible to producers sending soil samples to a commercial soil laboratory. The goal of this project is to incorporate soil properties into N availability prediction models for dairy manure to improve N use efficiency of field-applied manure.

What Did We Do?

A total of 16 different soil series were sampled throughout Oregon, Washington, and Idaho in major dairy producing counties at a 12-inch depth. These soils represent over 1.6 million acres in the Pacific Northwest (PNW). One solid dairy manure was sampled in Idaho and one composted dairy manure was sampled in Oregon to be applied to the soils during incubation. All the soils were analyzed for a full suite of soil physiochemical properties at a local soil testing laboratory. The manures similarly received a full analysis at the same laboratory.

We conducted a 12-week incubation of manure-amended soils at 77°F (25°C), sampling periodically for nitrate and ammonium to determine the difference in Nmin rates with changes in soil physiochemical properties. Approximately 1.1 lbs (500 g) of soil was added to 1-gallon Ziplock bags and brought to 80% field capacity. The soils were treated with dairy manure, composted manure, or no manure at a rate of approximately 400 lb N/acre (200 mg N/kg soil) with four replicates for each soil and treatment. Each of the 192 samples were randomly assigned a sample number corresponding to their location inside the incubator. The closed and loosely rolled bags were stored in 12 by 9 by 7-inch cardboard boxes, then placed inside an incubator at 77°F for 12 weeks. Soils were sampled at weeks 0, 2, 4, 8, and 12, where part of the sample was used to monitor soil moisture, and the other was frozen for future analysis. Analysis of the frozen samples for nitrate and ammonium content was conducted using a microplate spectrophotometer using vanadium (III) chloride and sodium salicylate methods, respectively.

What Have We Learned?

The analysis of frozen samples has just begun at the time of submission. Initial results will be available on the poster presented.

Future Plans

The next steps of this project are to conclude the nitrate and ammonium analysis of the soil samples and create Nmin curves with this data for each soil and treatment. These curves will be analyzed to determine if the differences in Nmin rates correlate with any of the tested soil physiochemical properties and which properties are most influential. Finally, we will create a model based on correlation data to express the changes in nitrogen mineralization depending on soil physiochemical properties that can be used by producers to adjust their dairy manure application rates depending on their soil test results.

Authors

Presenting author

Ryan A. Auld, Soil Science Graduate Student, Oregon State University

Corresponding author

Amber Moore, Extension Soil Fertility Specialist, Oregon State University, Amber.moore@oregonstate.edu

Additional authors

Jennifer Moore, Research Soil Scientist, Forage Seed and Cereal Research Unit, U.S. Department of Agriculture Agricultural Research Service; Yakun Zhang, Associate Professor, Oregon State University; Christopher Rogers, Research Soil Scientist, Northwest Irrigation and Soils Research, U.S. Department of Agriculture Agricultural Research Service

Additional Information

Build DAIRY

Acknowledgements

I’d like to acknowledge the BUILD Dairy program and the Oregon Dairy Farmers Association for their support of this project, as well as the many producers who have allowed me to sample soils from their farms.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2025. Title of presentation. Waste to Worth. Boise, ID. April 7–11, 2025. URL of this page. Accessed on: today’s date.

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Use of Orchard Debris for Vermifiltration: Advancing Regenerative Agriculture and Wastewater Treatment

Purpose

This study assesses the economic and air quality benefits of using chipped apple orchard wood as a carbon source in a vermifiltration wastewater system. Instead of burning orchard debris, which releases harmful pollutants, the Perca system repurposes it as a substrate for earthworm-microbial wastewater treatment. The study also compares apple wood chips to traditional conifer chips, evaluating their effectiveness and the broader environmental and economic advantages of diverting orchard waste.

What Did We Do?

Image 1. Chipping process of apple orchard tear-out debris using Morbark, Eeger Beever, 1621” x 18”x 20.5” feeder throat with 140 horsepower motor.
Image 1. Chipping process of apple orchard tear-out debris using Morbark, Eeger Beever, 1621” x 18”x 20.5” feeder throat with 140 horsepower motor.

Apple orchard tear-out debris from a local orchard was collected, chipped, and transported for installation as a substrate for the Perca vermifiltration system. Debris was screened to remove foreign materials, chipped to less than ½ inch size, and weighed to calculate tons of usable wood per ton of orchard debris. Data from processing, including chipping costs and labor requirements, were used to assess economic feasibility and air quality impact. In addition, a bench-scale test was conducted to evaluate the efficacy of wastewater treatment by apple orchard chips when compared to the standard conifer chips used in the Perca vermifiltration system. Removal efficiencies of total suspended solids (TSS), biological oxygen demand (BOD), and polychlorinated biphenyls (PCBs) were measured for both substrates.

Image 2. Example of foreign objects (wire) embedded in apple wood pieces.
Image 2. Example of foreign objects (wire) embedded in apple wood pieces.

Market projections for Perca’s vermifiltration system show a compound annual growth rate (CAGR) of 113.45%, reaching 9.57% of the market over the next five years. Calculated market projection estimates over 16,000 tons of orchard debris could be converted into a value-added substrate product rather than burning. This shift could eliminate more than 500 tons of emissions between 2025 and 2029. Economic analysis shows that while chipping costs and wood size restrictions pose challenges for trellised orchards, non-trellised orchards offer better yields and lower costs, with market trends and technology advancements pointing toward broader economic feasibility. Bench-scale tests showed that both apple wood and conifer substrates effectively reduced TSS, BOD, and PCBs by more than 80% in all categories with no significant difference in performance, confirming apple debris works as well as conifer media. These findings demonstrate that apple orchard debris provides an environmentally sustainable alternative to burning, thus contributing to improved air quality, while also an efficient, cost-effective vermifiltration substrate for wastewater treatment.

Image 3. Pine media and apple orchard tear-out fines.
Image 3. Pine media and apple orchard tear-out fines.
Image 4. Rapid Assay Vermifiltration System (RAVS) used to test wastewater contaminant removal capability in traditional (pine) media and apple orchard tear-out fines.
Image 4. Rapid Assay Vermifiltration System (RAVS) used to test wastewater contaminant removal capability in traditional (pine) media and apple orchard tear-out fines.

Future Plans

Ongoing efforts focus on refining the use of apple orchard debris to create a cost-effective, reliable wood chip that matches or exceeds current substrates in reducing conventional and nonconventional wastewater pollutants, while offering an economic alternative to burning. Additionally, strategies are being developed to integrate vermifiltration into regenerative agriculture and circular bioeconomy practices by repurposing spent substrate as a nutrient-rich soil amendment or for soil remediation. This approach transforms agricultural waste into multiple value-added resources, supporting both environmental sustainability and economic viability through continued innovation, collaboration, and stakeholder engagement.

Authors

Presenting & Corresponding author

Sierra J. Smith, Director of Research and Development, Perca, Inc., sierrasmith@perca.net

Additional authors

Joseph S. Neibergs, Professor Extension Economist and Director Western Center for Risk Management Education, Washington State University

George A. Damoff, Chief Science Officer, Perca, Inc.

David A. Elmenhurst, Chief Financial Officer, Perca, Inc.

Additional Information

perca.net

https://ecology.wa.gov/about-us/accountability-transparency/partnerships-committees/boards-councils/agricultural-burning-research-task-force

Acknowledgements

Washington State Department of Ecology for funding and support

Washington State Agricultural Burning Practices & Research Task Force, under direction of the Department of Ecology, for funding and support

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2025. Title of presentation. Waste to Worth. Boise, ID. April 7–11, 2025. URL of this page. Accessed on: today’s date. 

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Reducing Ammonia Emissions from Poultry Litter with Lignite and Lignosulfonate

Due to a technical glitch, we did not get this presentation recorded. Please accept our apologies.

Purpose

The purpose of this study was to determine the effectiveness of lignite, a low-quality coal, and lignosulfonate, a byproduct of paper milling, in reducing ammonia emissions from poultry litter.

What Did We Do?

We utilized a laboratory

 acid-trap chamber system to assess the effectiveness of varying rates of lignite and lignosulfonate on ammonia reduction when compared to an industry standard, sodium bisulfate (PLT), and an untreated control. In the volatilization experiment, 12 treatments were tested, including five application rates of lignite and lignosulfonate (0.75, 1.5, 3, 4.5, and 6 kg m-2), PLT, and an untreated control. Acid traps of 0.02 M phosphoric acid were changed 11 times over the 14-day experiment. Acid trap solutions were then analyzed for ammonia to quantify cumulative ammonia emissions.  

What Have We Learned?

Both lignite and lignosulfonate were effective in reducing ammonia volatilization in this laboratory setting. While both lignite and lignosulfonate required higher application rates to achieve the same ammonia reduction as PLT, these could be effective alternatives and should be further studied on a larger scale.

Future Plans

While we have no active plans to continue this work, future efforts should include small scale testing in a commercial setting, cost analysis, and sourcing options.

Authors

Presenting & Corresponding author

Stephanie Kulesza, Assistant Professor, North Carolina State University, sbkulesz@nscu.edu

Additional Information

This research is not yet published. Reach out to Stephanie Kulesza at sbkulesz@ncsu.edu if you would like to know more about this work.

The authors are solely responsible for the content of these proceedings. The technical information does not necessarily reflect the official position of the sponsoring agencies or institutions represented by planning committee members, and inclusion and distribution herein does not constitute an endorsement of views expressed by the same. Printed materials included herein are not refereed publications. Citations should appear as follows. EXAMPLE: Authors. 2025. Title of presentation. Waste to Worth. Boise, ID. April 7–11, 2025. URL of this page. Accessed on: today’s date.