water quality modeling – Livestock and Poultry Environmental Learning Community

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Purpose

A Best Management Practice (BMP) Expert Panel was convened under guidance of the Chesapeake Bay Program’s (CBP) Water Quality Goal Implementation Team to assess and quantify Nitrogen and Phosphorus load reductions for use in the Phase 6 Chesapeake Bay Watershed Model when manure is injected or incorporated into agricultural lands within the watershed. (Further description of Expert Panels and processes can be found in the 2017 Waste to Worth Proceedings and Presentation by Jeremy Hanson and Mark Dubin).

What Did We Do?

The Expert Panel first created definitions of injection and incorporation practices, which allowed technologies utilized in research to be categorized within each definition. Categorization considered the manner in which manure was placed beneath the soil surface as well as the level of surface disturbance. Manure injection was defined as a specialized category of placement in which organic nutrient sources (including manures, biosolids, and composted materials) are mechanically applied into the root zone with surface soil closure at the time of application with soil surface disturbance of 30% or less. Manure incorporation was defined as the mixing of dry, semi-dry, or liquid organic nutrient sources (including manures, biosolids, and compost) into the soil profile within a specified time period from application by a range of field operations (≤24hr for full ammonia loss reduction credit and 3 days for P reduction credit(s)). Incorporation was divided into categories of high disturbance (<30% residue retention) and low disturbance (>30% residue retention). Both liquid and solid manures were considered.

The panel conducted an extensive literature review of research that allowed comparison of nutrient loss after manure injection and incorporation with a baseline of surface manure application without incorporation. These comparisons were assembled in a large categorical table in percentage form, that reflected loss reduction efficiency. Many manuscripts offered a percentage comparison of application treatments to the surface application baseline. For research reports that did not provide a percentage comparison, the panel interpreted results into a percentage comparison when possible.

Consideration to soil variability and location in the Chesapeake Bay Watershed was considered on a very broad basis and in a manner consistent with work of other panels and modeling team recommendations. Loss reduction efficiencies were provided for soils or locations listed as either Coastal or Upland regions. Nitrogen efficiencies did not vary between the regions, but Phosphorus efficiencies did.

What Have We Learned?

Nitrogen and Phosphorus loss reduction efficiency reported or derived from literature varied within categories. For some categories, the volume of literature was small. Research providing these efficiencies is often conducted on small plots with simulated rainfall. Literary reduction results were often provided as a range and not as a single value. Professional scrutiny and judgment was applied to each value provided from literature and to all values within injection and incorporation categories to determine loss reduction efficiencies to be used in the broad categories of the model. The final loss reduction efficiencies of the Expert Panel’s final report are provided in Tables 1 (Upland Region) and 2 (Coastal Region).

Table 1. Loss reduction efficiency values for Upland regions of the Chesapeake Bay Watershed.

Category	Nitrogen			Phosphorus
Category	Time to Incorporation	Ammonia Emission Reduction	Reduction in N Loading¹	Time to Incorporation	Reduction in P Loading²
Injection	0	85%	12%	0	36%
Low Disturbance Incorporation	≤24 hr 24-72 hr	50% 34%	8% 8%	≤72 hr	24%
High Disturbance Incorporation	≤24 hr 24-72 hr	75% 50%	8% 8%	≤72 hr	0%³

¹ Reduction in N loading water achieved only for losses with surface runoff. The portion of total N loss through leaching is not impacted by the practices. 25% of total N losses to water are assumed to be lost with runoff (both dissolved N and sediment-associated organic matter N).

² Reduction in P loading water achieved only for losses with surface runoff. The portion of total N loss through leaching is not impacted by the practices. 80% of total P losses to water are assumed to be lost with runoff (both dissolved and sediment-bound P) in upland regions of the watershed.

³ Reduction in dissolved P losses typically offset by greater sediment-bound P losses due to greater soil erosion with tillage incorporation in upland landscapes.

Table 2. Loss reduction efficiency values for Coastal Plain region of the Chesapeake Bay Watershed.

Category	Nitrogen			Phosphorus
Category	Time to Incorporation	Ammonia Emission Reduction	Reduction in N Loading¹	Time to Incorporation	Reduction in P Loading²
Injection	0	85%	12% 12%	0	22%
Low Disturbance Incorporation	≤24 hr 24-72 hr	50% 34%	8% 8%	≤72 hr	14%
High Disturbance Incorporation	≤24 hr 24-72 hr	75% 50%	8% 8%	≤72 hr	14%

² Reduction in P loading water achieved only for losses with surface runoff. The portion of total N loss through leaching is not impacted by the practices. 48% of total P losses to water are assumed to be lost with runoff (both dissolved and sediment-bound P) in Coastal Plain.

Future Plans

The report of the Manure Injection and Incorporation Panel were accepted by the Chesapeake Bay Program’s Agricultural Workgroup in December 2016. The values will be utilized in Phase 6 of the Chesapeake Bay Watershed Model. Future panels may revisit the efficiencies as future model improvements are made.

Corresponding author (name, title, affiliation)

Robert Meinen, Senior Extension Associate, Penn State University

Corresponding author email address

rjm134@psu.edu

Other Authors

Curt Dell (Panel Chair), Soil Scientist, USDA-Agricultural Research Service

Art Allen, Associate Professor and Associate Research Director, University of Maryland – Eastern Shore

Dan Dostie, Pennsylvania State Resources Conservationist, USDA-Natural Resources Conservation Service

Mark Dubin, Agricultural Technical Coordinator, Chesapeake Bay Program Office, University of Maryland

Lindsey Gordon, Water Quality Goal Implementation Team Staffer, Chesapeake Research Consortium

Rory Maguire, Professor and Extension Specialist, Virginia Tech

Don Meals, Environmental Consultant, Tetra Tech

Chris Brosch, Delaware Department of Agriculture

Jeff Sweeney, Integrated Analysis Coordinator, US EPA

For More Information

Two related presentations given at the same session at Waste to Worth 2017

Acknowledgements

Funding for this panel was provided by the US EPA Chesapeake Bay Program and Virginia Tech University through an EPA Grant.

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. 2017. Title of presentation. Waste to Worth: Spreading Science and Solutions. Cary, NC. April 18-21, 2017. URL of this page. Accessed on: today’s date.

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Purpose

The Chesapeake Bay Program (CBP) is a regional partnership that leads and directs Chesapeake Bay restoration and protection. The CBP uses a suite of modeling and planning tools to estimate nutrient (nitrogen and phosphorus) and sediment loads contributed to the Bay from its watershed, and guide restoration efforts. Non-point source (NPS) pollutant sources (e.g., agricultural and urban runoff) are largely related to diverse land uses stretching across six states and the District of Columbia. On-the-ground pollutant reductions are achieved by implementing both management and structural best management practices (BMPs) on those diverse land uses. Short and long-term reductions in NPS pollutant loads that result from BMP implementation are estimated using the CBP modeling suite of tools. The CBP recognizes (i.e., represents pollutant reduction credits for) over 150 BMPs across 66 land uses total for all sectors in its Phase 6 suite of modeling tools. The estimated pollutant reduction performance (i.e., effectiveness) of each BMP is parameterized in the CBP modeling suite. Within the CBP, BMP effectiveness is determined by groups of qualified scientific and technical experts (BMP Expert Panels) that review the relevant literature and make an independent determination regarding BMP performance which are reviewed and approved by the CBP partnership before being integrated in to the modeling tools by the CBP modeling team.

BMP Expert Panels are primarily convened under the auspices of the CBP’s Water Quality Goal Implementation Team and tasked to specific sector workgroups for oversight and management. Panels are tasked with addressing a specific BMP, or a suite of related BMPs. Panel members, in coordination with the CBP partnership, are selected based on their scientific expertise, practical experience with the BMP, and expertise in fate and transport of nutrients and sediment. Panels review the relevant literature and through a deliberative process and form recommendations on BMP pollutant production performance, and how the BMP(s) should be accounted for/incorporated into the CBP modeling tools and data reporting systems. Convening BMP Expert Panels is an ongoing focus and priority of the CBP partnership, given the integral role BMP implementation plays in achieving the pollution reduction goals required by the 2010 Chesapeake Bay Total Maximum Daily Load (TMDL).

What Did We Do?

Expert panels follow the process and adhere to expectations outlined in the Chesapeake Bay Program Partnership’s Protocol for the Development, Review, and Approval of Loading and Effectiveness Estimates for Nutrient and Sediment Controls in the Chesapeake Bay Watershed Model (aka the “BMP Protocol”). The expert panel process functions as an independent peer review, similar to that of the National Academy of Sciences.

Each panel reviews and discusses all current published literature and available unpublished literature and data related to the BMP(s), and formulates recommendations using the guidance provided in the BMP Protocol to help weigh the applicability of each data source. Consensus panel recommendations are recorded in a final report, which is presented to relevant CBP partnership groups, including the CBP partnership’s Agriculture Workgroup for feedback and approval.

Panel recommendations are built into the modeling tools following CBP partnership approval of the panel’s report.

Chesapeake Bay Watershed Map

Basic Diagram of the Chesapeake Bay Program Expert Panel BMP Review Process

What Have We Learned?

The availability of published, peer-reviewed data varies greatly based on the scope of the panel. Some panels have dozens of articles to analyze while others may have a limited number of published studies to supplement gray literature, unpublished data and their best professional judgment. Even panels with a large amount of relevant literature at their disposal identify important gaps and future research needs. Given the wide range of stakeholders in the CBP partnership, regular updates and communication with interested parties as the panel formulates its recommendations is extremely important to improve understanding and acceptance of final panel recommendations.

Future Plans

The Chesapeake Bay Program evaluates BMP effectiveness estimates as new research or new conservation and production practices become available. Thus, expert panels sometimes revisit BMPs that were previously reviewed, but new and innovative BMPs are also considered. The availability of resources and new research limit the frequency of these reviews in conjunction with the priorities of the CBP partnership. Given the CBP partnership’s interest in adaptive management and continually improving its scientific estimates of BMP effectiveness, there will continue to be BMP expert panels for the foreseeable future.

Corresponding author (name, title, affiliation)

Jeremy Hanson, Project Coordinator – Expert Panel BMP Assessment, Virginia Tech

Corresponding author email address

jchanson@vt.edu

Other Authors

Mark Dubin, Agricultural Technical Coordinator, University of Maryland Extension

Brian Benham, Professor and Extension Specialist, Virginia Tech

Each expert panel has at least several other authors and contributors, which is not practical for listing here. Each individual report identifies the panel members and other contributors for that specific panel.

Additional Information

The BMP Review Protocol is available online at http://www.chesapeakebay.net/publications/title/bmp_review_protocol

All final expert panel reports are posted on the Chesapeake Bay Program website under “publications”: http://www.chesapeakebay.net/groups/group/bmp_expert_panels

Acknowledgements

These BMP expert panels would not be possible without the generosity of expert panel members who volunteer their valuable time and perspectives. Staff support, coordination and funding for these panels is provided by the EPA Chesapeake Bay Program, specifically through Cooperative Agreements with Virginia Tech and University of Maryland, with additional contract support from Tetra Tech as needed. The work of these expert panels is strengthened through the participation, review and comments of the CBP partnership.