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:
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- 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)
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- 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
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