Implications of Manure Additives: Both Purposeful and Accidental

This webinar discusses purposeful additives like nitrification inhibitors and biochar as well as accidental additives like copper sulfate from disinfecting foot baths and how these things can and should impact our decisions when applying manure. This presentation was originally broadcast on September 22, 2023.

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Nitrification Inhibitors and Manure

Melissa Wilson, University of Minnesota (15:57)

Presentation Slides

Adding Biochar into Manure Management

Joe Stanford, University of Wisconsin-Platteville (16:54)

Presentation Slides

Impact of copper sulfate footbath use on eastern Wisconsin’s manure, soil, and forage copper concentrations

Aerica Bjurstrom, University of Wisconsin-Madison (17:08)

Presentation Slides

Questions from the Audience

All presenters (12:41)

More Information

Continuing Education Units

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American Registry of Professional Animal Scientists (ARPAS)

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Winter Manure Application: Research Needs and Future Direction

To better understand the state of the science and to lessen the present risk of winter manure application, a literature review was conducted that examined a wealth of studies dating back to 1945. Interest in winter manure application has increased, in part, due to the high-profile nutrient impacts to the Great Lakes and the several resulting new policies that have been implemented within the surrounding states. Based on this literature review, research needs and future directions were identified.

What did we do?

A comprehensive literature review was conducted that included scientific, technology transfer, and regulatory documents.  Contaminants of concern, emerging pollutants, case studies, existing best management practices, state level policy, and key data gaps were identified.

What we have learned?

The US Environmental Protection Agency (EPA) and the Natural Resource Conservation Service (NRCS) discourages the application of manure in winter because of the elevated risk of nutrient loss to the environment as demonstrated by several field, laboratory, and modeling studies (Srinivasan et al., 2006). The emergence of environmental issues downstream of livestock operations such as algae blooms and fish kills has led some States to ban winter manure application all together, although some states still allow emergency applications and exempt smaller farms from the regulations. Additionally, the loss of nutrients during spring thaws means a loss of soil productivity for farmers and added expense to purchase soil amendments.
There are several parameters that ultimately determine the impact winter manure spreading will have on the environment and the nutrient content that remains in the soil after application. Included, but not limited to, are slope, soil type, depth of freeze, rate of thaw, depth of snow, presence of cover crops, tilling practices, manure moisture content, and timing of application. Several are interdependent, often resulting in difficulty isolating the relative effects of any particular parameter compared to another and, in some cases, contradictory research results are found. However, several general findings may still be derived, as discussed below.


Runoff from winter-applied manure can be an important source of annual nutrient loadings to water bodies, with nitrogen and phosphorous being the most often reported. In a 1985 study, Moore and Madison (1985) estimated that 25% of annual phosphorus load to a Wisconsin lake was directly attributable to winter spreading of animal wastes. Brown et al. (1989) investigated the Cannonsville Reservoir in New York and determined that snowmelt runoff from winter manured cropland contributed more phosphorus to the reservoir than runoff from barnyards. Clausen and Meals (1989) estimated that 40% of Vermont’s streams and lakes experienced significant water quality impairments from the addition of just two winter-spread fields in their watersheds. Plot studies of winter-applied manure found 23.5 to 1,086 mg/L of total Kjeldahl nitrogen (TKN) and 1.6 to 15.4 mg/L of phosphorus in runoff (Lorimor and Melvin, 1996; Thompson et al., 1979). In two Vermont field studies, Clausen (1990; 1991) reported 165 to 224% increases in total phosphorus concentration, 246 to 1,480% increases in soluble phosphorus, 114% increases in TKN, and up to a 576% increase in NH3-N following winter application of dairy manure. Mass losses of nutrients are highly variable across studies. Several studies have noted elevated, though moderate, mass losses of nitrogen ranging from 10-22% of applied nitrogen (Converse et al., 1976; Hensler et al., 1970; Klausner et al., 1976; Lorimor and Melvin, 1996; Midgley and Dunklee, 1945; Phillips et al., 1981). However, Owens et al. (2011) reported total nitrogen losses of 35-94%, by mass. These numbers are highly variable due the extreme variance in weather conditions, with flash events contributing more nutrient loss than slower melt events. Authors noted that it is possible for nearly all loss to occur in a single storm event (Klausner et al., 1976; Owens et al., 2011).

Steenhuis et al., (1979) reported decreases in ammonia volatilization rates for winter spread manure relative to spring due to lower temperatures. Lauer et al. (1976) showed that manure covered by snow had no signs of ammonia volatilization. These results suggested that limiting ammonia volatilization may be critical to nutrient retention in soil. However, Williams et al. (2010) showed that manure applied under snow did not truly maintain this ammonia but lost it through runoff. No case studies have quantified the reduction of other odor causing compounds such as di-hydrogen sulfide in winter applied manure relative to other seasonal applications.

Losses are contingent upon fields exhibiting certain risk factors (Klausner et al., 1976; Young and Holt, 1977; Young and Mutchler, 1976). Important are variations in local weather conditions, depth and type of soil freeze, the position of manure relative to the snowpack, and the timing of application relative to snow melt. Because of the large number of unconstrained variables in the natural environment, there continue to be disagreements on best management practices to limit nutrient movement. Additionally, the form of nutrient is critical. All of these factors impact the mechanisms of nutrient loss: plant uptake, sorption, polymerization, microbial degradation, volatilization, advective movement, and dispersive transport. Consequently, the fate of particulate forms may be very different than soluble, depending on the site and management-specific conditions.  

As such, the industry will benefit from continued experiment and field research in an effort to account for very specific, definable variables and nutrient form. Further, because of the extensive list of relevant variables, the development of precise and accurate mathematical models is essential as experimentally modeling the infinite number of site and management-specific conditions is impossible.


Several varieties of pathogens are common in livestock excrement, though not all pose human health risks. Pathogens of concern include the following (USEPA 2004; Rogers and Haines 2005; Sobsey et al. 2006; Pappas et al. 2008; Bowman 2009).

  • Bacteria: Escherichia coli (E. coli) O157:H7 and other shiga-toxin producing strains, Salmonella spp., Campylobacter jejuni, Yersinia enterocolitica, Shigella sp., Listeria monocytogenes, Leptospira spp., Aeromonas hydrophila, Clostridium perfringens, Bacillus anthraxis (in endemic area) in mortality carcasses.
  • Parasites: Giardia lamblia, Cryptosporidium parvum, Balantidium coli, Toxoplasma gondii, Ascaris suum and lumbricoides, Trichuris trichuria.
  • Viruses: Rotavirus, hepatitis E virus, influenza A (avian influenza virus), enteroviruses, adenoviruses, caliciviruses (e.g., norovirus).

As with nutrients, application of animal manure to impervious surfaces such as frozen ground can increase the risk of pathogen loss through runoff events relative to application in other seasons (Reddy, et al., 1981). Cool temperatures have been shown to improve the survival of fecal bacteria (Reddy et al., 1981; Kibbey, et al., 1978). However, field studies found that freezing conditions can be lethal to fecal bacteria (Kibbey, et al., 1978). While these reports hint at fecal bacteria being able to survive cool but not freezing conditions, Kudva, et al. (1998) reported E. coli surviving more than 100 days in manure frozen at minus 20°C. Conversely, freezing and thawing of a soil manure mixture was found to reduce E. coli levels by about 90% (Bicudo, 2003).

More research on this topic is needed to identify conflicting results. Of particular interest is the impact of warming soil temperatures. Slight variations can result in substantial microbial ecological changes. Further, it is well understood that the use of fecal coliform as a pathogen indicator is flawed. New microbial genetics techniques enable the identification of pathogens of greatest risk. Research should monitor for these specific, likely pathogens and their fate during freeze-thaw cycles.

Emerging Pollutants

Land application of both solid and slurry excrement has been cited as a vector for introduction of antimicrobials into the environment (Boxall 2008; Klein et al. 2008). In the early 2000s, it was estimated that approximately 60% to 80% of livestock and poultry routinely received antimicrobials through feed or water, injections, or external application (NRC 1999; Carmosini and Lee 2008). Though new best management practices involving non-therapeutic use of antibiotics in livestock are likely to decrease these percentages, estimated changes are not available. Livestock animals are estimated to discharge 70-90% of antibiotics administered through excrement (Massé et al., 2014). Approximately 55% of antimicrobial compounds administered to livestock and poultry are also used to treat human infections (Benbrook 2001; Kumar et al. 2005; Lee et al. 2007). The utilization of such overlapping antibiotics has been cited as a potential cause of antimicrobial resistance (Sapkota et al. 2007), a grave concern in modern medicine (Levy and Marshall 2004; Sapkota et al. 2007).

Antimicrobials are hydrophilic and do not readily break down in the environment and are, consequently, at high risk of introduction into water bodies through runoff events (Chee-Sanford et al. 2009; Zounková et al. 2011). Critically, these compounds show high adsorptive tendencies in soils and clays (Chee-Sanford et al. 2009), thus providing a potential for interception by soil.

Because antibiotics are highly hydrophilic, movement with melt water results, similar to soluble nutrients. Although this mechanism seems clear, movement during winter application is poorly understood. The mechanisms that determine their fate are the same as those listed for nutrients. However, this fate is poorly understood, especially regarding the amount that will reach the field and streams when comparing different seasonal applications. Further, some studies suggest prolonged storage in aerobic manure environments helps facilitate breakdown particularly at higher temperatures (Kumar et al. 2005; Lee et al. 2007; Boxall et al. 2008). However, the question remains whether these effects are present in winter storage.

Fate studies under diverse farm field conditions are essential. Further, the original compound may be broken down into metabolites, some of which may be even more dangerous. All original and breakdown products should be reviewed.

Benefits of Winter Manure Application

The soil health benefits of winter manure application appear to be limited. However, the literature suggests that soil compaction and nitrogen volatilization can be reduced when applying to frozen soil, but at the potential expense of nutrient runoff. There are also many benefits to agriculturalists, as Fleming and Fraser (2000) noted:

  • Reducing size and number of manure storage structures.
  • Spreading the manure when logistics suite the farmer.
  • Reducing soil compaction by avoiding equipment use during compressible soil conditions.

Management Practices

There is little standardization in regard to winter manure application and most states cite the NRCS conservation practice standard 590 for nutrient management (NRCS, 2013). In regard to winter manure application, this standard states the following. “Nutrients must not be surface-applied if nutrient losses offsite are likely. This precludes spreading on: frozen and/or snow-covered soils, and when the top two inches of soil are saturated from rainfall or snow melt. Exceptions for the above criteria can be made for surface-applied manure when specified conditions are met and adequate conservation measures are installed to prevent the offsite delivery of nutrients” (NRCS, 2013). As a continuation of standard 590, the NRCS states that at a minimum the following factors should be considered before winter manure application (NRCS, 2013):

  • Field slope
  • Organic residue and living covers
  • Amount and form of nutrients to be applied
  • Setback distances to protect local water quality
  • Application timing

The ambiguity in standard practices for winter manure application has led to several different State policies. States with winter manure application guidelines include Ohio, Pennsylvania, Michigan, and Illinois. States that have some form of bans include Vermont, Iowa, Maryland, Indiana, Minnesota, and Wisconsin. States not listed have policies that are identical to the NRCS standard 590.

Future Plans

Based on this literature review, needed research has been identified:

  • Review the incidences of emergency spreading on frozen ground versus incorporation during cold weather. Understanding the frequency and timing of emergency spread events is critical to crafting policy and best management practices.
  • Evaluate compliance with new rules and if intended impacts are realized, including comparing watershed level of target pollutants across state lines and time lines to view the impacts of this policy change.
  • Determine if application in early spring, when soil is saturated and precipitation events are frequent, is more desirable than in winter application before a deep freeze allows for incorporation. Related is the impact of soil moisture content on the fate of target pollutants during thaw events.
  • Determine the economic impact on producers and the potential loss of small to medium sized farms. One of the most often cited criticisms of unconditional winter manure application bans is that it can disproportionately disadvantage smaller producers. In a Michigan survey of small producers, 27% of non-CAFO dairy farmers suggested that they would need to suspend operations if such a ban were instituted (Miller et al., 2017). This same survey found that a total ban on winter application in Michigan would collectively cost small farms in that state an estimated $30 million dollars (Miller et al., 2017). An important task is to survey, with time, states that have banned winter manure application to determine if significant shift with regard to average producer size occurred. If so, it is important to consider the resulting economics of the environmental benefits and if national biosecurity decreased with a reduction in producers.
  • Verify the effectiveness of risk indices such as the Manure Application Risk Index (MARI), Wisconsin’s Online Manure Advisory System, and other individual states’ P-indices. Many of these indices were developed based on recommendations from research and the practical experience of experts, but literature verifying this is scarce.
  • Determine the impact of climate change on winter manure application policies. Climate change effects the duration and intensity of winter temperatures and the frequency and intensity of precipitation events. Such conditions may require more adaptable metrics such as frost depth, depth of snow, ability to incorporate, and forecasted thaw events.


Steven I. Safferman1, Jason S. Smith2, and Rachelle L. Crow3

1Associate Professor; Michigan State University, Biosystems and Agricultural Engineering; Corresponding Author:

2Teaching Specialist, Michigan State University, Engineering CoRe

3Undergraduate Research Assistant, Michigan State University, Biosystems and Agricultural Engineering

Additional information

  • Benbrook, C.M. 2001. Quantity of antimicrobials used in food animals in the United States. American Society for Microbiology 101st  Annual Meeting. May 20-24, 2001. Orlando, FL.
  • Bicudo, J. R., Goyal, S.M. 2003. Pathogens and manure management systems: a review. Environmental technology 24.1 (2003): 115-130.
  • Bowman, J. 2009. Manure pathogens: manure management, regulations, and water quality protection. p. 562.Water Environmental Federation, McGraw-Hill, New York.
  • Boxall, A. 2008. Fate and transport of veterinary medicines in the soil environment. p 123-137. In D.S. Aga (ed.) Fate and transport of pharmaceuticals in the environment and water treatment systems. 1st ed. CRC Press, Boca Raton, FL.
  • Brown, M.P., Longabucco, P., Rafferty, M.R., Robillard, P.D., Walter, M.F., Haith, D.A. 1989. Effects of animal waste control practices on nonpoint-source phosphorus loading in the West Branch of the Delaware River watershed. J. Soil Water Conserv. 44, 67–70.
  • Carmosini, N., Lee, L.S. 2008. Sorption and Degradation of selected pharmaceuticals in soil and manure. p 139-165. In D.S. Aga (ed.) Fate and transport of pharmaceuticals in the environment and water treatment systems. 1st  ed. CRC Press, Boca Raton, FL.
  • Chee-Sanford, J.C., Mackie, R.I., Koike, S., Krapac, I.G., Lin, Y., Yannarell, A.C., Maxwell, S., Aminov. R.I. 2009. Fate and transport of antibiotic residues and antibiotic resistance genes following land application of manure waste. Journal of Environmental Quality. 38(3):1086-1108.
  • Clausen, J.C. 1990. Winter and Fall application of manure to corn land. Pages 179 – 180 invMeals, D.W. 1990. LaPlatte River Watershed Water Quality Monitoring and AnalysisProgram: Comprehensive Final Report. Program Report No. 12. Vermont WatervResource Research Center, University of Vermont, Burlington.
  • Clausen, J.C. 1991. Best manure management effectiveness. Pages 193 – 197 in Vermont RCWP Coordinating Committee. 1991. St. Albans Bay Rural Clean Water Program, Final Report. Vermont Water Resources Research Center, University of Vermont, Burlington
  • Clausen, J.C., Meals, D.W. 1989. Water quality achievable with agricultural best management practices. J. Soil Water Conserv. 44, 593–596.
  • Converse, J.C., Bubenzer, G.D., Paulson, W.H. 1976. Nutrient losses in surface runoff from winter spread manure. Trans. ASAE 19, 517–519.
  • Fleming, R., Fraser, H. 2000. Impacts of winter spreading of manure on water quality: Literature review. Ridgetown, Ontario, Canada Ridget. Coll. Univ. Guelph.
  • Hensler, R.F., Olsen, R.J., Witzel, S.A., Attoe, O.J., Paulson, W.H., Johannes, R.F. 1970. Effect of method of manure handling on crop yields, nutrient recovery and runoff losses. Trans. ASAE 13, 726–731.
  • Kibbey, H.J., Hagedorn, C., and McCoy, E.L. 1978. Use of fecal streptococci as indicators of pollution in soil.  Applied Environmental Microbiology. 35:711-717.
  • Klausner, S.D., Zwerman, P.J., Ellis, D.F. 1976. Nitrogen and phosphorus losses from winter disposal of dairy manure. J. Environ. Qual. 5, 47–49.
  • Klein C., O’Connor, S., Locke, J., Aga, D. 2008. Sample preparation and analysis of solid-bound pharmaceuticals. p. 81-100. In D.S. Aga (ed.) Fate and transport of pharmaceuticals in the environment and water treatment systems. 1st  ed. CRC Press, Boca Raton, FL.
  • Kudva, I. T., Blanch, K., Hovde, C. J. 1998. Analysis of Escherichia coli O157: H7 survival in bovine or bovine manure and manure slurry. Applied and environmental microbiology, 64(9), 3166-3174.
  • Kumar, K., Gupta, S.C., Chander, Y., Singh, A.K. 2005. Antibiotic use in agriculture and its impact on the terrestrial environment. Advances in Agronomy. 87:1-54.
  • Lauer, D.A., Bouldin, D.R., Klausner, S.D. 1976. Ammonia volatilization from dairy manure spread on the soil surface. J. Environ. Qual. 5, 134–141.
  • Lee, L.S., Carmosini, N., Sassman, S.S., Dion, H.M., Sepúlveda, M.S. 2007. Agricultural contributions of antimicrobials and hormones on soil and water quality. Advances in Argronomy.93:1-68.
  • Levy, S.B., Marshall, B. 2004. Antibacterial resistance worldwide: causes, challenges and responses.  Nature Medicine Supplement. 10(12):S122-S129.
  • Lorimor, J.C., Melvin, J.C. 1996. Nitrogen losses in surface runoff from winter applied manure. Final Report. Univ. Iowa, Ames, Iowa.
  • Massé, I.D., Saady, M.N., Gilbert, Y. 2014. Potential of Biological Processes to Eliminate Antibiotics in Livestock Manure: An Overview. Anim. . doi:10.3390/ani4020146
  • Midgley, A.R., Dunklee, D.E. 1945. Fertility runoff losses from manure spread during the winter. Agricultural Experiment Station; Burlington.
  • Miller, S.R., Mann, J.T., Leschewski, A., Rozeboom, D., Safferman, S., Smith, J. 2017. Survey of Small Michigan Livestock Winter Manure Handling and Economic Assessment of Policy Change, in: 2017 ASABE Annual International Meeting. American Society of Agricultural and Biological Engineers, p. 1.
  • Moore, I.C., Madison, F.W. 1985. Description and application of an animal waste phosphorus loading model. J. Environ. Qual. 14, 364–369.
  • NRC. 1999. The use of drugs in food animals: benefits and risks. Food and Nutrition Board, Institute of Medicine. National Academy Press, Washington, DC.
  • NRCS. 2013. Conservation Practice Standard 590: Nutrient Management [WWW Document]. URL (accessed 1.8.17).
  • Owens, L.B., Bonta, J. V, Shipitalo, M.J., Rogers, S. 2011. Effects of winter manure application in Ohio on the quality of surface runoff. J. Environ. Qual. 40, 153–165.
  • Pappas, E. A., Kanwar, R. S., Baker, J. L., Lorimor, J. C., Mickelson, S. 2008. Fecal indicator bacteria in subsurface drain water following swine manure application. Transactions of the ASABE, 51(5), 1567-1573.
  • Phillips, P.A., Culley, J.L.B., Hore, F.R., Patni, N.K. 1981. Pollution potential and corn yields from selected rates and timing of liquid manure applications. Trans. ASAE 24, 139–144.
  • Reddy, K. R., Khaleel, R., Overcash, M. R. 1981.  Behavior and transport of microbial pathogens and indicator organisms in soils treated with organic wastes. Journal of Environmental Quality, 10(3), 255-266.
  • Rogers, S., and J. Haines. 2005. Detecting and mitigating the environmental impact of fecal pathogens originating from confined animal feeding operations: review. EPA-600-R-06-021. USEPA, Office of Research and Development, National Risk Management Research Laboratory. Cincinnati, OH.
  • Sapkota, A.R., F.C. Curriero, K.E. Gibson, and K.J. Schwab. 2007. Antibiotic-resistant enterococci and fecal indicators in surface water and groundwater impacted by a concentrated swine feeding operation. Environmental Health Perspectives. 115(7):1040-1045.
  • Sobsey, M.D., Khatib, L.A., Hill, V.R., Alocilja, E., Pillai, S. 2006. Pathogens in animal wastes and the impacts of waste management practices on their survival, transport and fate. p. 609-666. In J.
  • Srinivasan, M.S., Bryant, R.B., Callahan, M.P., Weld, J.L. 2006. Manure management and nutrient loss under winter conditions: A literature review. J. Soil Water Conserv. 61, 200–209.
  • Steenhuis, T.S., Bubenzer, G.D., Converse, J.C. 1979. Ammonia volatilization of winter spread manure.  Trans.of ASAE. p 152-157, 161.
  • Thompson, D.B., Loudon, T.L., Gerrish, J.B. 1979. Animal manure movement in winter runoff for different surface conditions, in: Best Management Practices for Agriculture and Silviculture Proceedings of the 1978 Cornell Agricultural Waste Management Conference, P 145-157, 1979. 1 Fig, 4 Tab, 16 Ref.
  • USEPA. 2004. Risk management evaluation for concentrated animal feeding operations. EPA-600-R-04-042.USEPA, Office of Research and Development, National Risk Management Research Laboratory, Cincinnati, OH.
  • Williams, M.R., Feyereisen, G.W., Beegle, D.B., Shannon, R.D., Folmar, G.J., Bryant, R.B. 2010. Manure application under winter conditions: Nutrient runoff and leaching losses, in: 2010 Pittsburgh, Pennsylvania, June 20-June 23, 2010. American Society of Agricultural and Biological Engineers, p. 1.
  • Young, R.A., Holt, R.F. 1977. Winter-applied manure: Effects on annual runoff, erosion, and nutrient movement. J. Soil Water Conserv.
  • Young, R.A., Mutchler, C.K. 1976. Pollution potential of manure spread on frozen ground. J. Environ. Qual. 5, 174–179.
  • Zounková, R., Klimešová, Z., Nepejchalová, L., Hilscherová, K., Bláha, L. 2011. Complex evaluation of ecotoxicity and genotoxicity of antimicrobials oxytetracycline and flumequine used in aquaculture. Environmental Toxicology and Chemistry, 30(5), 1184-1189.


This project was funded by the North Central Regional Water Network Manure and Soil Heath Working Group and the Soil Health Institute.

The references for the original reports follow:



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. 2019. Title of presentation. Waste to Worth. Minneapolis, MN. April 22-26, 2019. URL of this page. Accessed on: today’s date.

The Michigan EnviroImpact Tool: A Supporting Tool to Help Farmers in Forecasting Manure Nutrient Runoff Risk

The purpose of the MI EnviroImpact Tool is to provide farmers with a daily runoff risk decision support tool that can aid in effectively planning short-term manure and nutrient application. This not only helps keep nutrients on the field and potentially saves money, but it also helps to protect our waterways in Michigan.

Lifecycle of manure nutrients
Figure 1. Livestock operations are a readily available source of manure nutrients. With effective nutrient application, farmers might be able to reduce the use of commercial fertilizers and save money.
With the MI EnviroImpact tool, farmers are able to plan for effective short-term manure application.
Figure 2. With the MI EnviroImpact tool, farmers are able to plan for effective short-term manure application.

What did we do?

Farmer interest groups were pulled together for initial piloting and testing of the MI EnviroImpact tool to hear what worked and what needed improvement. The goal was to make this a very user-friendly tool that everyone could use. Additionally, educational and outreach materials were created (factsheet, postcard, YouTube videos, and presentations) to help get the word out about this decision support tool. The ultimate goal of the MI EnviroImpact tool is for use as a decision support tool for short-term manure and nutrient application. The tool derives the runoff risk forecast from real-time precipitation and temperature forecasts. This information is then combined with snow melt, soil moisture and temperature, and other landscape characteristics  to forecast times when the risk of runoff will be higher. The MI EnviroImpact tool is applicable in all seasons and has a winter mode for times when the average daily snow depth is greater than 1 inch or the 3-day average soil temperature (top 2 inches) is below freezing.

The MI EnviroImpact tool displaying both winter and non-winter modes of daily runoff risk.
Figure 3. The MI EnviroImpact tool displaying both winter and non-winter modes of daily runoff risk.

What did we learn?

Through our work with the MI EnviroImpact Tool and those that helped to develop this tool, we were able to spread awareness of this user-friendly tool, so that more farmers would be likely to use it to help in nutrient application planning. Furthermore, those outside of the farming community have been very encouraged to see that agriculture is continuing to take steps in being environmentally friendly. Additionally, others have viewed this tool as a resource outside of farmers, showing that the MI EnviroImpact Tool has broader implications than just agriculture.

Future Plans

Future plans include continuing education about the MI EnviroImpact Tool as well as continued distribution of educational materials to help spread awareness of the tool itself.

Additional Information

Those who would like to learn more about the MI EnviroImpact Tool can visit the following links:


This project was prepared by MSU under award NA14OAR4170070 from the National Oceanic and Atmospheric Administration, U.S. Department of Commerce through the Regents of the University of Michigan. The statements, findings, conclusions, and recommendations are those of the author(s) and do not necessarily reflect the views of the National Oceanic and Atmospheric Administration, the Department of Commerce, or the Regents of the University of Michigan.

MSU is an affirmative-action, equal-opportunity employer, committed to achieving excellence through a diverse workforce and inclusive culture that encourages all people to reach their full potential. Michigan State University Extension programs and materials are open to all without regard to race, color, national origin, gender, gender identity, religion, age, height, weight, disability, political beliefs, sexual orientation, marital status, family status or veteran status. Issued in furtherance of MSU Extension work, acts of May 8 and June 30, 1914, in cooperation with the U.S. Department of Agriculture. Jeff Dwyer, Director, MSU Extension, East Lansing, MI 48824. This information is for educational purposes only. Reference to commercial products or trade names does not imply endorsement by MSU Extension or bias against those not mentioned.

Partners and funding sources involved in supporting, developing, and implementing the MI EnviroImpact tool.
Figure 4. Partners and funding sources involved in supporting, developing, and implementing the MI EnviroImpact tool.

Project Collaborators:

Heather A. Triezenberg, Ph.D.
Extension Specialist and Program Leader, Michigan Sea Grant
Michigan State University Extension
Community, Food and Environment Institute
Fisheries and Wildlife Department
Meaghan Gass
Sea Grant Extension Educator
Michigan State University Extension

Jason Piwarski
GIS Specialist
Michigan State University
Institute of Water Research

Dustin Goering
Senior Hydrologist
North Central River Forecast Center
NOAA National Weather Service

Cindy Hudson
Communications Manager, Michigan Sea Grant
Community, Food & Environment Institute
Michigan State University Extension

Jeremiah Asher
Assistant Director
Institute of Water Research
Michigan State University

Kraig Ehm
Multimedia Producer
ANR Communications and Marketing
College of Agriculture and Natural Resources
Michigan State University

Luke E. Reese
PhD, Associate Professor
Biosystems and Agricultural Engineering
Michigan State University

Marilyn L. Thelen
Associate Director, Agriculture and Agribusiness Institute
Michigan State University Extension

Todd Marsee
Senior Graphic Designer
Michigan Sea Grant
University of Michigan

Mindy Tape
ANR Communications & Marketing
Michigan State University Extension



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. 2019. Title of presentation. Waste to Worth. Minneapolis, MN. April 22-26, 2019. URL of this page. Accessed on: today’s date.

Wisconsin Professional Manure Applicator Education

Why Look at Manure Applicator Educational Programs?

Based on 2013 statistics, Wisconsin has a dairy herd of 1.2 million cows that produce 12,000,000,000 gallons of manure and waste water. Custom manure haulers in Wisconsin handle an estimated fifty percent of the dairy manure and forty per cent of all livestock manure generated in Wisconsin. Because custom manure applicators are a critical component of nutrient management plan (NMP) implementation, University of Wisconsin Extension initiated manure hauler education across the state in the early 1990’s. In 2000, the applicators sought UW – Extension advisory support in forming the Professional Nutrient Applicators Association of Wisconsin (PNAAW). This began a long term relationship between UW – Extension and the professional applicators in Wisconsin and across the upper Midwest.

Following a needs assessment of the industry, the board of directors of PNAAW expressed an interest in a voluntary training and certification program. The overall goal of the training was to educate the custom manure haulers and their employees in safe handling and application practices, spill response, regulations and nutrient management. Road safety, neighbor relations, and confined space safety education modules were added later.

What did we do?

In March of 2002, the board of directors of the PNAAW and a group of Michigan manure applicators independently approached Extension in each state to initiate a voluntary certification and training program. Over the next 5 months, applicators and Extension staff examined the 5 existing manure applicator certification programs and created the program currently in use in Wisconsin, Illinois and Michigan.

Field photo 2012

Manure expo 2012, checking out a new dragline applicator.

The UW – Extension Nutrient Management Team’s Custom Manure Hauler Workgroup joined with Extension faculty in Illinois and Michigan to develop a three-state certification program with three levels of training/certification. The certification includes a partnership with the insurance industry to provide a market-based incentive to participate. Business and employee management issues are addressed during an annual multi-state regional symposium coordinated by UW-Extension.

Certification: The program is segmented into three certification levels. Firms must meet level 1 requirement to gain level 2, and meet level 2 requirements to achieve level 3.

  • Level 1: Requires each employee to be trained and tested on spill response techniques, state specific regulations (including CAFO regulations) and common sense application techniques. Firms that document compliance are eligible for a 10% vehicle liability premium reduction. Training is ~3 hours in length and is completed annually.
  • Level 2: Requires crew supervisors and business owners to attend 6 hours of continuing education over a 2 year period. Classes are offered at field days and the annual conference. Once a firm has achieved Level 2, they may conduct Level 1 training in-house.
  • Level 3: Develop and implement an EMS (Environmental Management System). The EMS requires the firm to document their process and ensure all employees know their job responsibilities. Insurance auditors will evaluate each firm’s EMS annually to insure compliance. Premium reductions include 10-40% on vehicle liability and 50% on environmental liability.

Not your typical Wisconsin “boat” show. PNAAW 2014 manure boat agitation demonstration, organized with UW-Extension.

All certification levels also require that the firm complete the PNAAW Performance Standards Checklist at least once per year.

Membership in the state’s applicator association is required for certification, as certification is granted by the association and not by Extension. Each state association may also require additional performance standards, such as documentation of equipment calibration, to grant certification.

One area of continuing education began in 2002, when UW – Extension with permission from Wisconsin Department of Natural Resources (WDNR), conducted manure spill response training using actual manure. The basic educational focus was containing, controlling, cleaning up, and then meeting reporting requirements of a spill. Since 2002, 20 live action demonstrations have occurred. Training has expanded to include calibrating of manure equipment and determining manure application rate per acre.

What have we learned?

PNAAW requested that Extension assist in filling an educational need not met by current farm shows – being able to compare different manure agitation and application equipment side by side in the field (using actual manure) to help determine which best meets individual needs. The result was the first Manure Expo in August 2001, which drew 432 people from 5 states and Canada.

The Manure Expo has grown to an annual 2-day educational and demonstration event. 2015 is the 13th Expo; the event has been hosted by Extension and custom applicators in Wisconsin, Michigan, Minnesota, Ohio, Iowa, Missouri, Nebraska, and Pennsylvania in the US and Guelph, Ontario, Canada. An average Expo will draw over 1,000 people from industry, university, farm, and application professionals.

PNAAW 2014

PNAAW 2014

The pit before the boat demonstration begins 2014.

The voluntary certification program has saved Wisconsin and Michigan over $100,000 annually because regulatory mandates require state finances for staff and office to run mandated programs. In addition to the sharing of curriculum in multiple Midwestern universities the training and educational sessions are a success in the formation/enhancement of three state associations in Michigan (now inactive), Pennsylvania, and Indiana/Ohio.

Applicator and industry partnerships contributed to a multi – state agriculture weight study based at the Minnesota DOT/University of Minnesota, MN Road Research Center. Over $640,000 was pooled from applicators and Applicator Associations (WI, MI, MN, IA, and OH), industry and agencies to fund research on the impact of larger manure hauling and agriculture equipment on pavement.

Custom manure applicators are a key component in the environmental application of manure. The Wisconsin Department of Agriculture, Trade, and Consumer Protection (DATCP) has tracked crop acres managed with a NMP. In 2004, 0.7 million crop acres were managed using a NMP; in 2014 the NMP managed acres increased to 2.58 million acres in Wisconsin.

Future Plans

Each year a new need will arise. Education will be provided for employee relations, business planning, family/work balance and the need to review new technology. A few projects that began in 2014: manure boat agitation field day and precision manure application. Education will be developed in the future as a need arises from the manure application industry.


Richard Halopka, CCA, Clark County UW-Extension Crops & Soils Agent

George Koepp, Columbia County UWEX Agriculture Agent, Jerry Clark,Chippewa County UWEX Crops/Soils Educator, Ted Bay, Grant County UWEX Crops/Farm Management Agent, Kevin Erb, UWEX Conservation Professional Devp. & Training Cord., Becky Larsen, UW Biowaste Specialist, Jim Leverich, UW On Farm Research, Kim Meyer, UW Arlington ARS, Cheryl Skjolaas, UW Agriculture Safety Specialist

Additional information

In 2014, over 400 custom manure applicators in Wisconsin were certified in at least one level of the program. Eight PNAAW member application firms revised their level 3 status in 2013 and are saving $44,000 annually on pollution insurance policies, while PNAAW firms achieving level 1 and level 2 certification reduced pollution insurance policies premiums by an additional $78,000 per year.

The collaboration of PNAAW, University of Wisconsin Extension, University of Wisconsin Specialists, WDNR, DATCP and UW – Extension County Agents has provided the foundation of a proactive approach to education and training, leading to problem solving results from a knowledgeable application industry.  

2009 U.S.A. water quality poster, manure spills

2009 U.S.A. water quality poster, manure spills

Bulletin for manure spill response developed by UW-Extension nutrient management team PNAAW workgroup.

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. 2015. Title of presentation. Waste to Worth: Spreading Science and Solutions. Seattle, WA. March 31-April 3, 2015. URL of this page. Accessed on: today’s date.

Grid Soil Sampling to Guide Manure Application

Why Consider Grid Sampling for Manure Application?

Grid soil sampling for phosphorus and potassium can identify areas in fields with nutrient deficiencies and other areas with sufficient or excess nutrients. Nutrient maps can be used to define areas for manure application or exclusion, using supplemental fertilizer where manure is not applied or does not meet the crop requirements. The overall effect is to increase the fertilizer-replacement value of the manure, conserving its use for nutrient deficient fields and field areas. Related: LPELC Manure Nutrient Management

Each of the case studies was conducted on a Minnesota farm and presents the method to:

  • determine crop nutrient needs
  • create manure application and exclusion zones from nutrient maps
  • estimate the value of manure under whole-field vs zoned application, and
  • evaluate practices to reduce off-site soil and nutrient loss for the specific field analyzed.


The case studies do not discuss variable rate manure application, but do assume capability for supplemental fertilizer application, with or without variable rates.

For More Information

Les Everett, Agronomist, University of Minnesota Water Resources Center

How do you calibrate a manure spreader?

Calibrating a manure spreader is critical to ensure that the appropriate rate of manure nutrients is being applied to a field. For some livestock operations, this practice may be a required practice as part of their permit. Calibration will differ depending on the equipment and type of manure being applied.

If you know the capacity of the spreader, you need to determine the width of each pass and the distance it takes to empty the spreader to determine the rate of application. A measuring wheel is a useful tool and can often be borrowed from a local Cooperative Extension or Natural Resources Conservation Service (NRCS) office. After you have determined both of those measurements, use the charts in the publication linked below to determine application rate.

If the capacity of the manure spreader is unknown and solid manure is being spread, you can use a process that involves setting out plastic sheets or tarps of known size and driving the manure spreader over them and weighing the amount of manure that is collected on the sheets. A 22-square-foot tarp is a convenient size because the net weight of the manure on the sheet will be equal to the application rate in tons per acre. A step-by-step guide on making these calculations for other size tarps is available in the publication linked below.

For more, including specifics on calibrating solid, liquid, and irrigation manure equipment, visit Calibrating Manure Application Equipment.

Author: Jill Heemstra, University of Nebraska Extension Educator

A Review of Manure Injection to Control Odor and Ammonia Emissions During the Land Application of Manure Slurries

Reprinted, with permission, from the proceedings of: Mitigating Air Emissions From Animal Feeding Operations Conference.

The proceedings, “Mitigating Air Emissions from Animal Feeding Operations”, with expanded versions of these summaries can be purchased through the Midwest Plan Service.

This Technology is Applicable To:

Species: Swine, Dairy, Beef
Use Area: Land Application
Technology Category: Management (manure injection/incorporation)
Air Mitigated Pollutants: Odor, Ammonia

System Summary

Manure slurry injection provides a significant reduction in land application odor and ammonia emissions release when compared to conventional manure surface broadcasting. Release of odor and ammonia during land application can be reduced by more than 90% compared to conventional application methods (Ohio State University, 2007). Manure can be successfully injected in both conventional tillage and no-till systems with currently available equipment. Additionally, slurry tanker wagons currently used for broadcast application can also be retrofitted with Injection tool bars.

Research by Hanna et al., (2000) compared the odor and ammonia emissions from various types of manure injection techniques to slurry that was surface applied (broadcasted). Odor and ammonia tests were run for both fall and spring slurry application. Ammonia was below the detection limit (0.2 ppm) for all but two (measured at 0.6 and 1.3 ppm) of the 72 samples taken. Broadcast application required approximately four to five times more fresh air dilutions than injection to reach the odor threshold (the level at which the odor can no longer be detected) indicating much lower odor release associated with injection.

Applicability and Mitigating Mechanism

  • Injection tools create sub-surface cavities
  • Slurry is injected into the cavity directly behind the tool
  • Injection minimizes slurry exposure to air reducing odor and ammonia volatilization
  • Injection can be used with all slurry and liquid manures


  • Injection systems are not currently commercially available for solid manures
  • Injection can require up to 30% more tractor horsepower than broadcast
  • Injection may not be desirable when the producer does not want the soil or crop root system disturbed (forages, pasture/sod)
  • Injection equipment requires more maintenance than broadcast equipment


Generally, injection is more costly than broadcast application. Injection requires more tractor horsepower and more equipment (injection tool bars). Because tool bars are pulled through the soil, wear and maintenance is greater with injection systems. Cost increases as application rate decreases and distance from the manure storage site increases. The increase in cost as application rate decreases is due to wear on the application equipment. At lower application rates, field speed is increased causing wear (and eventually maintenance) on the equipment to increase. At a 5,500 gallons per acre application rate, commercial drag hose injection cost is currently $.014/gal compared to $.0085/gal for broadcast (Puck, 2008).


Ross Muhlbauer1, Jeremy Puck2, Ben Puck2, Robert Burns1, 1Iowa State University, 2 Puck Custom Enterprises
Point of Contact:
Ross Muhlbauer,

The information provided here was developed for the conference Mitigating Air Emissions From Animal Feeding Operations Conference held in May 2008. To obtain updates, readers are encouraged to contact the author.