SERA17: Organization to Minimize Phosphorus Loss from Agriculture

(Multistate Research Coordinating Committee and Information Exchange Group)

Status: Active

SERA17: Organization to Minimize Phosphorus Loss from Agriculture

Duration: 10/01/2023 to 09/30/2028

Administrative Advisor(s):

NIFA Reps:

Non-Technical Summary

Statement of Issues and Justification

Nutrient runoff from agriculture continues to be one of the major causes of water quality impairment in the U.S. and around the world.  Thus, there continues to be a need for information on the fate and transport of nutrients, especially phosphorus (P) and as appropriate nitrogen (N), where water quality is concerned, in order to develop and implement efficient and cost-effective conservation practices (CPs) to reduce the potential for loss.


Over the last 30 years, there has been a dramatic increase in the number and range of research and extension personnel investigating the fate and transport of P and N in agricultural and urban runoff.  This has increased the need for communication and collaborative research among extension personnel, which facilitates comprehensive and unified research-based extension information and reduces the possibility for fractured and contradictory information.  Thus, there continues to be a need for SERA-17 as a resource for research and extension on issues related to agricultural management that affect nutrients, runoff, conservation and water quality. The main justification for continuing the organizational entity of SERA-17 is to develop cost-effective solutions to manage P in agricultural systems to reduce environmental impact while ensuring sustained production. The impact of SERA-17 comes by ensuring that these solutions are used by policy makers and other important stakeholders (e.g., USEPA, NRCS, non- governmental organizations (NGOs), and state agencies) and educators. Our focus on P has been our strength. We are a volunteer group of over 300 members that consists largely of university faculty and USDA scientists who work to integrate research and extension around agricultural phosphorus management. A critical theme of SERA-17 is consensus-driven science. As new issues arise where scientific consensus is needed, the SERA-17 community develops such consensus through discussion and debate and produces findings that are used by the global community.

The SERA-17 community has four primary objectives, with specific goals over the next five years. The Universities of North Carolina State, Iowa State, Delaware, Kentucky, Florida, Maryland, Minnesota, Arkansas, Waterloo, and Saskatchewan will be participating in Objective 1. The Universities of Delaware, North Carolina, Saskatchewan and the USDA-ARS will participate in Objective 2. All of these universities as well as the USDA-ARS, and Environment and Climate Change Canada (ECCC) and Agriculture and Agri-food Canada (AAFC) will contribute to Objective 3. Objective 4 will be largely contributed to by the Universities of Delaware, North Carolina State, Tennessee, Minnesota, Kentucky, Waterloo, Saskatchewan and Wisconsin, as well us USDA-ARS, Canadian government (ECCC, AAFC) and industry consultants.


  1. Advance the science around P in the landscape, with an emphasis on agriculture.
  2. Develop standardized, robust protocols for field, lab and modeling efforts for advancing the science around P bioavailability, fate, and transport in the landscape
  3. Respond to stakeholders on priority areas related to P management in agriculture.
  4. Communicate the science to the knowledge-users through information-sharing and development of toolkits and indices

Procedures and Activities

An overarching goal of SERA-17 is to bring together a diversity of disciplines to discuss, disseminate, coordinate, and facilitate the research and management needs related to the management of nutrients (particularly P), their transport in surface and subsurface flows, and their impact on the quality of receiving waters.

Previous Activities

SERA-17 was launched in 1994 as a home for researchers, managers and others to collaborate in developing scientific consensus around the science and management of agricultural P. SERA-17 is inextricably linked to the P Index, a site assessment tool that has been adopted and adapted world wide, as well as the focus of the majority of SERA-17’s early activities. As a tool used in educating and guiding P management, the P Index offered a framework that integrated the many facets of P fate in agronomic systems. SERA-17 systematically organized researchers to carry out cross-site efforts that, through their coordination, were comprehensive and definitive. As a result, SERA-17 has been very successful in informing and guiding policies and programs aimed at mitigating P losses from agriculture, and has demonstrated an ability to respond rapidly to emerging issues where timely representation of scientific consensus was needed. While the majority of SERA-17’s members are from the U.S. and Canada, its membership extends across the globe. SERA-17 continues to represent a truly international activity and is the “go-to” organization for expert, up-to-date science-based information on mitigation of water quality impairment through nutrient stewardship (particularly P), and soil conservation. 


Over the past 25 years, SERA-17 has had accomplishments in 4 key areas:

  1. Advancing the science:

    1. Historically focused on understanding P losses; Tackled uncertainty/controversy and advanced the science around P in landscapes, especially agriculture. There has always been strong interaction between SERA 17 and other disciplines/groups.

    2. The P Index served to organize and direct science on P fate and transport, from representation of site hydrology related to P transport to experimentation that quantified interactions between source and transport factors.

    3. Provided foundation for understanding how P is represented in process-based models, including a review of the state of the science and direction on modeling priorities (Radcliffe and Cabrera).

    4. Understanding P mobilization in subsurface transport (Sims et al,; King et al.).

  2. Developed robust protocols and provided guidance on experimental and observational work

    1. Standardized methods for rainfall – runoff studies (Daniel et al.).

    2. Established relationships between STP and runoff (Sharpley et al).

    3. Standard protocols for analyzing P in soils, sediments and waters (Pierzynski 1, Kovar v 2).

    4. Standard method for measuring water extractable P in manure (Kleinman et al.).

  3. Responding to stakeholders

    1. Led the development and implementation of the P Index.

    2. Response to the revision of USDA’s Nutrient Management Standard.

    3. Development of CP fact sheets.

    4. Routine review of guidelines, including by locating the annual meetings in areas where P science and management are in need of input.

  4. Communicated the science – for example, SERA-17 developed ‘toolkits’ and ‘indices’ and communicated these to agencies and managers

    1. Development of a website:

    2. Development and refinement of P Indices.

    3. STP runoff relationships integrated into P indices.

    4. Fertilizer Recommendation Support Tool (FRST; - STP runoff relationships integrated into nutrient management planning process.

    5. White papers to communicate the state of the science.


Proposed New Activities:

Over the next five years our goals under these broad objectives are:

  1. Advance the Science around P in the landscape, with an emphasis on agriculture.

    1. Legacy P – advance understanding of the term overall, and identify critical legacy P sources and forms, and the time lags associated with legacy P in the environment

    2. P drawdown in soils as a means to reduce P losses in runoff

    3. Climate change – understanding the importance of extreme weather and the efficacy of conservation practices under such conditions to prepare for the future

    4. Improved understanding of P recovery from waste streams - exploring the potential for P recovery in struvite and capturing P from manures

  2. Develop updated standardized, robust protocols for field, lab and modeling efforts for advancing the science around P in the landscape

    1. Update methods of soil P testing

  3. Communicate the science to the knowledge-users through information-sharing and development of toolkits and indices

    1. Publish revised, updated factsheets

    2. Publish a manual for P testing in soils, sediments, residuals and waters (based on updated protocols in 2a).

  4. Respond to stakeholders as needed.

Working Groups

Subgroups within the SERA-17 community work together in “Working Groups” in response to emerging and priority issues. These workgroups become ‘dormant’ once they are no longer active. In the past, there have been working groups around topics such as: Aquatics, CPs, Modeling, and Policy, Testing, and Transport.  Our current active working groups include:

Legacy P - This working group is currently working on a paper that explores current views on legacy P in the landscape.

Testing- This group is looking at updating the methods manual for P analysis - soil, water, wastewater which was published in 2009.          

P drawdown - This group is working to gather data from published P drawdown studies and is extracting data  from those papers for analysis. The group will perform a meta-analysis and decision tree analysis looking for the strongest predictors of P drawdown pace, such as soil type, crops, and management.

CP Factsheets - This group is currently updating the SERA-17 factsheets, which identify and promote practices that control nutrient loss, especially P, from agriculture.

Modeling - We will seek to promote activities by SERA-17’s modelling workgroup, recruiting new modelers and evaluating the potential to update related SERA-17 publications. In particular, opportunities exist to examine new stochastic (machine learning/ai) and process-based models addressing P transport and cycling in agrocecosystems. Recent efforts around P fate-and-transport in cold regions, legacy P, and decision-support may be leveraged. An assessment of the state-of-the-practice will be encouraged.

Expected Outcomes and Impacts

  • An annual meeting of members. Currently, this is associated with the Annual American Society of Agronomy, Crop Science, and Soil Science Meeting for two years. The third year, SERA-17 meets independently at a different location in the U.S. or Canada, where local members volunteer to organize the meeting and obtain funds to support the meeting.
  • County agents, government officials and citizens will be educated on important and timely agricultural phosphorus issues through two-page factsheets. These factsheets will be available on the SERA-17 website.
  • Agricultural phosphorus policy issues will be relayed to federal and state government officials through whitepapers and state-of-the-science reports that are prepared and published by SERA-17 members on key, topical issues related to the management of agricultural nutrients and water quality impacts. These reports are available on the SERA-17 website.
  • Standardization of analyses for forms of P in soils, residuals, manures, water, and environmental risk assessments are critical for comprehensive, comparative research that transcends geo-political and disciplinary boundaries. Thus, state-of-the-science publications of methods of analyses for forms of will continue to be maintained and new results published.
  • Education is an important role of this organization and will be continued by the publication of books printed by commercial publishers on a range of issues ranging from conservation management to modeling the fate and transport of P in the environment.
  • To ensure that the best science is supported by federal agencies responsible for agriculture and water quality, recommendations for revision of NRCS and USEPA nutrient management policy, at the request of these agencies.
  • Water resource issues cross state boundaries and are increasingly contentious. This group will try to provide consensus-based scientific guidance and leadership when they are asked to help lessen potential litigation.

Projected Participation

View Appendix E: Participation

Educational Plan

One of the goals of the SERA 17 group is to Communicate the Science. Some of this is done at annual meetings in which researchers, industry, government and other stakeholders work together to exchange ideas and co-develop solutions.

The SERA 17 community also provides guidance through published works, available on the SERA 17 website (Publications). The SERA 17 group has also published a series of factsheets that are also available on the website. These are currently being updated. 


SERA-17 leadership is provided by an in-coming chair, a current-year chair, and a past-chair.  For each two-year period, a new chair is elected at the annual SERA-17 meeting and leadership begins on a calendar year basis.  The chair is responsible for the annual program in consultation with the past and in-coming chairs.  Each workgroup has a leader, who is selected every two years.  White paper development is provided by temporary committees composed of SERA-17 members with subject-matter expertise.

Literature Cited

Daniel, T. et al. National research project for simulated rainfall-surface runoff studies. Available online:

King, K.W., Williams, M.R., Macrae, M.L., Fausey, N.R., Frankenberger, J., Smith, D.R., Kleinman, P.J. and Brown, L.C., 2015. Phosphorus transport in agricultural subsurface drainage: A review. Journal of environmental quality, 44(2), pp.467-485.

Kleinman P, Sullivan D, Wolf A, Brandt R, Dou Z, Elliott H, Kovar J, Leytem A, Maguire R, Moore P, Saporito L, Sharpley A, Shober A, Sims T, Toth J, Toor G, Zhang H, Zhang T. 2007. Selection of a water-extractable phosphorus test for manures and biosolids as an indicator of runoff loss potential. J Environ Qual. 36(5):1357-67. doi: 10.2134/jeq2006.0450. PMID: 17636298.

Kovar, J.L., Pierzynski, G.M. 2009. Methods of Phosphorus Analysis for Soils, Sediments, Residuals, and Waters-Revised Edition. Southern Cooperative Series Bulletin. Available:

Pierzynski, Gary. (2000). Methods of Phosphorus Analysis for Soils Sediments Residuals and Waters. North Carolina S. Univ.. 396. 

Radcliffe, D.E. and Cabrera, M.L., 2006. Modeling phosphorus in the environment. CRC Press.

Sharpley, Andrew & Kleinman, Peter & Wright, Bob & Daniel, T. & Joern, Brad & Sobecki, Terry. 2002. The National Phosphorus Project: interfacing agricultural and environmental phosphorus management in the USA. 

Sims, J.T., Simard, R.R. and Joern, B.C., 1998. Phosphorus loss in agricultural drainage: Historical perspective and current research. Journal of environmental quality, 27(2), pp.277-293.


Land Grant Participating States/Institutions


Non Land Grant Participating States/Institutions

Log Out ?

Are you sure you want to log out?

Press No if you want to continue work. Press Yes to logout current user.

Report a Bug
Report a Bug

Describe your bug clearly, including the steps you used to create it.