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Evaluation of Nutrient Management Practices
Mark Dubin, University of MarylandSteve Dressing, Tetra Tech
Agriculture Workgroup (AgWG) Meeting January 12, 2012
Tetra Tech Support-Collect Technical and Modeling Information on NM BMPs
N-based nutrient management P-based nutrient management Precision/Decision agriculture Enhanced nutrient management Form, Method, Rate, and Timing Cropland, Nurseries*, and Pasture*
N mineralization
P indexes*Have expertise on Panel
Tetra Tech Support -Collect Technical and Modeling Information on NM BMPs
Technical information on practices implemented in federal/state programs in CB Watershed
Operational conditions relative to these practices: Program guidelines Permits Regulations Restrictions
Tetra Tech Support -Collect Technical and Modeling Information on NM BMPs
Work with modelers to identify how BMPs will be handled in current applicable CBP models
Help incorporate into BMP definitions and effectiveness estimation information to support data tracking, reporting, and analysis requirements of CB models
Tetra Tech Support-Interviews
Why? To obtain research papers, project reports, fact sheets,
websites, etc. that can provide information on NM BMPs To obtain information on areas where BMPs are
implemented and programs that have adopted the BMPs Who?
Expert Panel members State agriculture program experts Other experts identified by AgWG and Panel
Tetra Tech Support-Scientific Literature Search
To assist NM Expert Panel BMP definitions BMP effectiveness
Tt searches and screens articles for applicability, usefulness, and quality
Peer-reviewed literature back to January 1, 1985 Tt provides citations and abstracts
Tetra Tech Support-Teleconferences and Meeting Support
Help set up teleconferences for Expert Panel Assist with meetings as appropriate
Tetra Tech Support-Evaluation Recommendations
Compile available information for each BMP identified by Panel for recommendation
Assist Panel in developing BMP definitions and effectiveness values
Follow criteria for Phase II TMDL, Current Progress Reporting (Phase 5.3.2), and Phase III TMDL Planning (Phase 6.0)
Seek a balance between the science and practicality
Tetra Tech Support-Review Process
Source Sector Review Assist with presentations of Panel recommendations for review by AgWG for
recommendation of approval by the Water Quality Goal Implementation Team (WQGIT)
Technical components of recommendation
Technical Review Assist with presentation of Panel recommendations for review by the
Watershed Technical Workgroup (WTWG) for recommendation of approval by the WQGIT
Modeling components, tracking, and reporting
Recommendation Approval Assist with presentation of Panel recommendations for review by the WQGIT
for final approval Process used and consistency with existing approved BMPs
Tetra Tech Support-Documentation and Reporting
Documentation and Reporting Fully document completed and approved BMP
evaluations Report to include the documentation and reporting
elements delineated in BMP Protocol.http://archive.chesapeakebay.net/pubs/Nutrient-Sediment_Control_Review_Protocol.pdf
AgWG Recommendations to Expert Panel
Use pre-1995 nutrient recommendations as a reference for determining non-NM rates.
Non-NM application rates should be higher than NM in all cases (a possible minimum of 5% of the NM rate).
Apply bio-solids in the model monthly to accurately represent field conditions; may need to develop a separate land use and condition vs. manure.
Application of NM as a BMP vs. a land use change to improve transparency and reflect actual field level changes.
Programmatic differences between states due to programs and regulations.
Agricultural NM will be evaluated separately from urban NM but a summit will be held to ensure a uniform
approach.
Considerations:
AgWG Recommendations to Expert Panel (cont.)
Manure volumes, fate, and distribution in the models for NM and non-NM on a regional and local scale.
Decision ag is very broad in definition; affects sequencing in the models which can occur differently for various operations. Soil testing Crop tissue testing Variable rates Split applications Incorporation/injection Slow release materials
Incorporating program changes into the future. Organic sources of N on legumes – intermediate (base applications on P vs. N) Limiting fall fertilization of small grains on residual N – intermediate (track as
commodity cover crops)
AgWG Recommendations to Expert Panel (cont.)
Applications setbacks for 10-35 ft. depending on nutrient source and application method.
Eliminate winter applications to turn off nutrient applications for all nutrients; bio-solids, manure, and fertilizer.
Use interim or alternative methods with the current modeling to better represent current NM benefits; e.g. report as decision ag in the future.
More clearly define levels of NM to assist with tracking, reporting, and verification.
Values of one- vs. three-year NM plans for reporting and model credit. NM management changes for irrigation; e.g. more consistent nutrient
uptakes.
AgWG Recommendations to Expert Panel (cont.)
P management tools and data such as from P-I applications to represent P NM changes due to genetics, yields, and production management over time
affecting nutrient updates and removal. Current conditions of agronomic recommendations that may more closely
match plant requirements; e.g. limited benefit of Yield Reserve. Fertilizer application methods in the models which are currently automatic;
should be able to “turn off” applications. Edge of stream delivery for sediment does not appear to be representative
similar to P processes.
AgWG Recommendations to Expert Panel (cont.)
Creating increased transparency of model representation of NM applications and BMPs; capable to reflect regional and local conditions.
Total N and P pools of nutrients available for application in the models versus automated applications.
The balancing of time required for NM planning and implementation vs. tracking, reporting, verification and model data support.
NM evaluation approaches that demonstrate actual impacts vs. standard values; empower the states to report performance through NM effectiveness, soil tests, etc.
CEAP results in evaluation; recommend an NRCS representative on panel. Standard tracking and reporting by jurisdictions is needed, growing
importance of NM and production data in the model; specific definitions are needed to reclassify “NM”.
AgWG Recommendations to Expert Panel (cont.)
Alternate forms of nutrient losses from field applications such as tile drainage (vertical) that could impact effectiveness.
NM may be different for nutrient sources; e.g. manure sources, fertilizer, nursery, pasture, etc.
The averaging of data in the models now cannot provide the level of detail needed to drive water quality for the future – consider new data sets to define performance such as PSNT and CSNT as examples.
AgWG Recommendations to Expert Panel (cont.)
The ability of the models to accept new sources of data from the states to supplement existing data sources.
The concern with transparency of the models is due to complexity – decisions made may have other consequences; adding more rules decreases transparency.
Averaging an acre for nutrient management is not applied in the field, decisions are made by specific crops and conditions – the models need to represent actual processes for nutrient applications and recommendations.
Yield data are currently used to drive plant uptake; which does not adequately represent changes in weather, crop acreages, etc.
PSNT and CSNT are taken to perform adaptive management based on soil and plant processes, but may be able to back calculate performance levels for modeling.
AgWG Recommendations to Expert Panel (cont.)
Changes to defined land uses and appropriate management scenarios are within the ability of the AgWG and the Panel to recommend for the 2017 models.
Alternative options, pilot counties, distributive model vs. lump parameter model, may take longer than a 2017 model.
Evaluate research data from individual farms not only of the effectiveness values but also inputs and outputs (mass balance) for comparing to the model processes.
SB needs to account for multi-year process of nutrients not a single year as of now.
Mineralized N for manure is three years and bio-solids is for 10 years under university recommendations; SB only represents year 1 and the WSM represents years 2-3 as well.
Formula for N forms could be changed; e.g. nitrates vs. ammonia.
AgWG Recommendations to Expert Panel (cont.)
P soil saturations, P limiting applications, etc. with regard to the reporting of P-based plans for future reporting/planning.
Plant genetics changes to nutrient uptake requirements is not reflected in the model data; yield data over past Ag Census data is represented but may not be a good measure of genetic changes.
Negative nutrient balances are not adequately represented in the models, all crop needs are in reality not always met or supplied by manure vs. fertilizer- a model structure question.
Proposal for Interviews
Nutrient Management Expert Panel Survey tool
• Emphasis on BMP definition and effectiveness• Literature, fact sheets, studies, etc.
Sent to Panel in advance of scheduled call Call to discuss Panel responses and more
• Dr. Michael D. Smolen• Dr. Deanna Osmond
Summary of calls for Panel
Proposal for Interviews
State agriculture program experts Survey tool
• Emphasis on State programs• Program guidelines, permits, regulations, restrictions
State profiles sent to experts in advance of call Call to discuss expert responses and more Summary of calls for Panel
Other experts identified by AgWG or Panel
Discussion and Additional Experts
Discussion of interview proposal Recommendations for additional experts to
interview
Schedule
December: Tt starts literature search. Panel selection.
January: Panel conference call. Interviews and collection of program info.
Early February: Summary of interviews.
Early February: Citations/abstracts for retrieved literature-first draft. Summary of program information.
Mid February: Consult with modelers on BMP incorporation.
Mid February: Panel initial findings to AgWG.
Early March: Preliminary information for use in Phase 2 WIPs.
March–June: Panel continues research on BMPs. Prepares for reviews and approvals.
June/July: Final recommendations from Panel.
July: Source Sector Review. July: Technical Review. August: Approval meeting for
WQGIT. August/September: Final report
Contact Information
Steve DressingTetra Tech, Inc.10306 Eaton Place, Suite 340Fairfax, VA 22030
