EPA Report Collection
Regional Center for Environmental Information
U.S. EPA Region II!
Philadelphia, PA 19103
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Regional Center for Environmental Information
-------
Recommendations for Coordinating
Phosphorus-Based Nutrient Management
in the Chesapeake Bay Region
Developed by the Agriculture Nutrient Management Workgroup of the
Chesapeake Bay Program's Nutrient Subcommittee
Membership
Doug Goodlander, Pennsylvania State Conservation Commission
Jerry Griswold, NRCS with the Chesapeake Bay Program
Tom Juengst, Pennsylvania Department of Environmental Protection
Russ Parkinson, Virginia Department of Conservation and Recreation
F. Fred Samadini, Chair, Maryland Department of Agriculture
Randy Shank, Virginia Cooperative Extension
Julie Trask, Chesapeake Bay Program
Ron Wood, Virginia Chesapeake Bay Local Assistance Department
Contributors to the Report
Doug Beegle, Perm State University
Greg Binford, University of Delaware
Frank Coale, University of Maryland
Louise Lawrence, Maryland Department of Agriculture
Greg Mullins, Virginia Tech
Jim Pease, Virginia Tech
Jennifer Weld, Perm State University
Facilitators
Phil Favero, University of Maryland
Victor Tervala, University of Maryland
,>,S. EPA Region III
Regional Center for Environmental
Information
1650 Arch Street (3PM52)
Philadelphia, PA 19103
-------
INTRODUCTION
Recently, the Chesapeake Bay Program, the Natural Resource Conservation Service
(NRCS) and the scientific community have begun to place a greater emphasis on the role
phosphorus plays in nonpoint source1 pollution. This increased awareness of the risks of
excess phosphorus in the soil profile and its relationship to water quality has led to NRCS
guidance and Environmental Protection Agency-proposed regulations. These proposed
EPA regulations would require operators to implement nutrient control practices for
nitrogen and phosphorus in their farm nutrient management plans for confined animal
feeding operations (CAFOs). Nutrient control practices for nitrogen and phosphorus will
likely become a requirement for farms that meet certain federal criteria. Also, other
federal or state programs may require new practices with respect to phosphorus. For
farming operations that use only commercial fertilizers, this shift should not be
burdensome. However, due to the ratio of phosphorus to nitrogen in animal wastes and
biosolids, phosphorus-based nutrient management planning may be a more arduous task
for livestock and poultry operations as well as for permitted sewage sludge applications.
In addition to the nutrient content of manures, the economics of farming encourages
farmers to apply animal wastes based on nitrogen needs of the desired crop. These two
factors have led to the over-application of phosphorus, which in turn has resulted in
phosphorus-enriched soils in certain locations.
PHOSPHORUS-BASED NUTRIENT
MANAGEMENT-PLANNING WORKSHOP AND QUESTIONNAIRE
The Agriculture Nutrient Reduction Workgroup of the Chesapeake Bay Program's
Nutrient Subcommittee held a one-day conference on "Coordinating Phosphorus-Based
Nutrient Management Policies in the Chesapeake Bay Region" on March 29, 2001.
Agronomic scientists and program implementation staff came together and presented
information on phosphorus management in agricultural systems. The objective of the
conference was to begin building consensus concerning questions and issues pertaining to
phosphorus-based (P-based) nutrient management policies within the region.
Several weeks after the conference, the workgroup distributed a questionnaire to all
participants following up on a formal discussion at the end of the conference. The
follow-up discussion focused on remaining issues and the use of a phosphorus index.
(See Appendix 1 for a summary of the questionnaire and results.) The original workshop
focused on the current science and implementation of phosphorus management, and the
participants were selected accordingly.
'Nonpoint Source Pollution: A diffuse source of pollution that cannot be attributed to a clearly identifiable,
specific physical location or a defined discharge channel. This includes nutrients that runoff the ground
from any land use - croplands, feedlots, lawns, parking lots, streets, forests, etc. - and enter waterways. It
also includes nutrients that enter through air pollution, groundwater or from septic systems.
http://www chesapeakebay.net/commirtee.htm.
-------
PHOSPHORUS-BASED NUTRIENT MANAGEMENT PLANS:
THREE FEDERAL MANAGEMENT OPTIONS
NRCS guidelines and proposed EPA regulations would require states to use one of the
following three methods to develop phosphorus-based nutrient management plans for
recipients of NRCS technical and financial assistance or for those operations that fall
under the requirement to obtain animal waste permits.2
(1) Soil Test Phosphorus (STP)
When STP levels are used, phosphorus may be applied at rates consistent with the
following: If the STP level is low or medium, plans can be nitrogen-based. If the
STP level is high, very high or excessive, plans will be phosphorus-based. For
example, a high test level could allow phosphorus application based on crop
removal, and an excessive test level would not allow any phosphorus application.
(2) Soil Phosphorus Threshold Level (PTH)
When soil-specific phosphorus threshold values are available, phosphorus may be
applied at rates consistent with the following: If a soil test is less than 3/4 PTH,
plans can be nitrogen-based. If the STP is equal or greater than % PTH and less
than 1 !/2 PTH, phosphorus can be applied at the level of crop removal. If the soil
test phosphorus is equal or greater than 1 1A PTH and less than 2 PTH, phosphorus
can be applied at !/2 the level of crop removal. If the soil test phosphorus is equal
or greater then 2 PTH, no phosphorus can be applied.
(3) Phosphorus Index (PI)
When the PI is used, phosphorus may be applied at rates consistent with the
following. If the PI rating is low or medium risk, the plan can be nitrogen-based.
If the PI rating is high risk, phosphorus can be applied at the crop removal level.
If the PI rating is very high risk, phosphorus cannot be applied. (Some
jurisdictions refer to the PI as the Phosphorus Site Index, or PSI.)
A fourth alternative not addressed in NRCS guidance is a combination of any previously
mentioned options. For example, use of Soil PTH to determine if a PI needs to be used.
WORKGROUP ISSUES
In deciding which method to recommend, the individuals polled had to consider many
variables, for example, ease of administration, political feasibility, regional flexibility and
scientific validity, among others. Of those that responded, 60 percent recommended that
the Bay region states adopt the use of the PI. Of the 40 percent that did not pick the PI, 30
percent picked a combination of methods and 10 percent picked STP or the Phosphorous
Threshold. Eighty percent believed that if a PI is adopted for use, a simplified screening
tool, based on a limited number of inputs such as soil test and slope, should be used to
determine whether a detailed PI value must be calculated for the field. Key advantages of
a PI include: state-to-state flexibility, a balanced approach to protecting the environment
2 NRCS: www.nhq.nrcs.usda.gov/BCS/nutri/gm-190.htm]
-------
that would take into consideration farming constraints, and a consideration of all
parameters that affect water quality. While the majority of those responding chose the
use of a PI, it was also recognized that such a choice has its pitfalls.
Major concerns regarding the use of PI were the complexity and the feasibility of
performing it on every field or management unit. Of those responding, 78 percent
concurred that states should have the flexibility to incorporate a "screening tool" within
the PI, which should make its field use more practical. One probable such tool is STP.
The PI could be calculated for those sites that exceed a predetermined value of the
screening tool used. Other possible screening tools could include the amount of soil
erosion and the proximity to surface water.
The participants were asked to what degree of specificity the input data should be
gathered for the more subjective components of a PI, for example, field slope, soil
permeability, distance to stream, etc. Fifty percent of the respondents suggested that the
use of existing data sets, such as soil surveys, should be used to the maximum extent
practical. The remaining respondents were concerned about the validity of using such
broad data, adding that proper nutrient management planning requires a field visit during
which the necessary data is collected.
The workgroup also discussed the use of "caps" on each individual component of the PI.
A cap is a level of a particular PI element that, when reached by the single element of the
index, places that field or management unit into the highest level of phosphorus
restrictions, regardless of the level of the other PI parameters documented for that factor.
The group concluded that more study is needed to determine if caps on individual
components (e.g. erosion, runoff or leaching risks) of the PI would be beneficial to the
process.
The survey also centered on the bioavailability of phosphorus in the soil and the
subsequent risk to loss via biological and physical pathways. Specifically, should the
various forms of phosphorus (organic and inorganic) be weighted in the PI? The
respondents concluded that further analysis is needed to quantify the effects of various
forms of phosphorus on water quality. Regarding the use of aluminum sulfate (alum), the
general consensus was that because of the many questions associated with the use of
alum (such as the potential for aluminum toxicity); a credit for alum use should not be
considered at this time. Again, further work is needed to assess the long-term benefits and
risks of alum use.
See Appendix 2 for a list of potential information gaps and research needs identified by
the workshop and survey results.
MOVING SURVEY RESULTS INTO RECOMMENDATIONS
Results of the questionnaire were reviewed at a September 13, 2001 follow-up meeting
(see Page 3 for list of attendees). From that meeting, the results of the questionnaire were
evaluated and a list of recommendations developed for consideration by the Chesapeake
Bay Program's Nutrient Subcommittee. The recommendations were developed based on
consensus. Consensus was defined as a decision that everyone could support. The
-------
Agricultural Nutrient Reduction Workgroup prepared the following summary of the
recommendations from that meeting. The survey and the survey results are also included.
RECOMMENDATIONS FOR PHOSPHORUS MANAGEMENT
IN THE CHESAPEAKE BAY REGION
The Chesapeake Bay Program should consider the following recommendations when
promoting phosphorus management within the Bay watershed:
1. States should consider adopting a PI approach as the basis for the phosphorus
component of their nutrient management planning. The PI may incorporate a screening
tool in the nutrient management planning process (where the site exceeds a
predetermined screening tool value).
2. Implementation of the PI should be simplified as much as possible while still
maintaining technical credibility by using existing data sets, such as the use of soil survey
map units to determine the average slope of each site.
3. Sensitivity analysis concerning the effects of various forms of phosphorus (e.g.,
ortho, organic or insoluble paniculate phosphorus) on Bay water quality should be
performed as a basis for individual weights for the forms of phosphorus within the index.
4. The benefits of placing caps on individual components of the PI should be based on
existing and future research. Caps could be placed on relevant components of the PI (for
example, those that exceed certain soil test or erosion levels) that would automatically
require full PI analysis.
5. There is a nutrient imbalance in the Chesapeake Bay region. The PI is a tool to assist
farmers and nutrient management planners in prioritizing the application of animal
wastes to minimize the impact of the current imbalance, but in itself the PI is not a
solution to the nutrient surplus in the Bay region. The members of this group and the
Chesapeake Bay Program should continue to investigate a broad array of solutions to the
nutrient surplus problem.
-------
APPENDIX I
QUESTIONNAIRE RESULTS SUMMARY
Question 1: What assistance is needed to implement P-based nutrient management
planning in your area?
General Responses: Education, financial assistance for manure transport, other off-farm
uses, value-added processing and marketing. Planning and research where applicable is
also needed.
Question 2: NRCS guidance and proposed EPA regulations would require states to use
one of three methods to develop phosphorus-based nutrient management plans for
permits. Which of the following methods should be adopted by states in the region: A.
STP Level; B. Threshold; C. PI; or D. a combination of the above?
Question 3: If a PI is adopted, should a simplified screening tool based on a very limited
number of inputs such as soil test phosphorus and slope be used to determine if a detailed
PI value needs to be calculated?
Related Considerations Provided for Question 3:
1. Ease of implementation.
2. Ability to exclude areas that do not contribute to the phosphorus problem.
3. Discriminating quality of the method used.
4. Political feasibility: citizens, producers and political representatives.
5. Scientific validity.
6. Overall effectiveness in treating the problem.
7. Prior experience in using the method (education).
8. Includes the ability to evaluate or measure the transport potential.
9. Accounts for all factors affecting P export from agricultural lands.
10. Site specific.
11. Flexible instrument.
12. Provides management options for producers.
13. Serves as an educational tool.
14. Impact on producers' burden.
15. Possess the technical capacity to implement.
16. Ease of monitoring outcome.
17. Allows phosphorus application at replacement rate.
18. Cost to landowners.
Final recommendation for questions 2 and 3: We recommend the adoption of a PI as
the basis for the phosphorus component of nutrient management planning. The PI may
incorporate a screening tool as an integral element of the nutrient management planning
process.
Question 4: If a screening tool is adopted, should the method: A. Require a PI to be
calculated for all sites that exceed a predetermined value of the screening level; B.)
-------
Require a PI to be calculated for all sites below a predetermined value of the screening
level; or C.) a combination of the above?
Final Recommendation: If a screening tool is adopted, the complete PI should be
calculated for all sites that exceed a predetermined screening tool value(s).
Question 5: Inorganic, water-soluble forms of phosphorus are immediately available to
aquatic plants, while particulate phosphorus associated with sediment or organic matter
becomes available slowly, over time. Both forms are lost to surface waters. How should
particulate phosphorus be weighted relative to inorganic water-soluble phosphorus losses
in a PI?
Final Recommendation: Consideration of the relative weighting of the various forms of
phosphorus should be based on the short- and long-term impact of each form on water
quality.
Question 6: Should there be caps on individual components of the PI?
Final Recommendation: The consideration of caps on individual components of the PI
should be based on existing or future research. Possible caps could include soil test
phosphorus level, erosion loss and fertilizer/manure phosphorus loading rates.
Question 7: Concerning the level of complexity of data input for a PI, what process
should be adopted in the Chesapeake Bay region—detailed field data collection vs. use of
existing data sets and proxies?
Final Recommendation: Collect and assess data onsite and use existing data sets where
relationships have been established.
Question 8: Should alum use be given credit in phosphorus-based nutrient management
plans?
Final Recommendation: There is promising research that could qualify the use of alum,
but researchers are not able to answer this question at the present time. More study of the
long-term affects and use of alum is needed.
Question 9: A previously unmanured site that tests medium in soil test phosphorus is
being considered for a new swine operation. A PI is calculated to arrive at a moderate
risk. However, once soil test phosphorus levels reach 280 ppm phosphorus for this site,
the PI will be very high, indicating that no further phosphorus applications are
recommended. If you are the permit issuing authority, what should you do?
-------
Final Recommendation: Farmers should be advised of their options and the
consequences of every action. Ultimately this is a business decision made in relation to
program and permit requirements. The permit issuing authority needs to educate the
farmer in all the implications of the law.
Question 10: If phosphorus-based nutrient management planning identifies a surplus of
manure for a given farming operation, what policy should be put in place to deal with the
exported manure?
General Responses: Financial assistance for manure transport. Keep manure in the state
where it is generated. A nutrient management plan should be required for receiving
farms. Rely on the market value approach. Use a phosphorus screening tool and run the
PI on the receiving farm. Soil test the receiving farm. Nitrogen- and phosphorus-based
plans - all users of fertilizer should be treated equally.
Question 11: Do you think the use of a PI will improve water quality?
General Responses: The bulk of the responses supported use of the PI for improving
water quality. The detailed comments stated that the PI is currently the best method to
achieve P reductions, but monitoring and efficient implementation is needed. The water
quality effects of the PI were not discussed extensively in follow-up discussions.
Question 12: What other suggestions or questions do you have pertaining to
implementation of phosphorus-based nutrient management policies in the Chesapeake
Bay region?
General Responses: We need to educate citizens and farmers, and to promote research
and monitoring; other tools need to be explored as well, such as dietary changes.
Consider the remediation and redistribution of manure. We need more education and
technical training, and to understand the economics of phosphorus-based nutrient
management planning. In addition, there should be uniformity on phosphorus-based
planning among the states. Nutrient balances should be completed county-by-county for
all sources. We need to understand overtime how soil phosphorus levels change as
phosphorus-based nutrient management takes place.
10
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APPENDIX II
INFORMATION AND RESEARCH NEEDS
RELATED TO THE PHOSPHORUS INDEX
The following items are extracted from the report text and questionnaire results:
• The complexity and the feasibility of performing the PI on a large number of
fields or management units.
• The validity of using existing reference data sets compared to onsite collected
data.
• More study is needed to determine if "caps" on individual components (e.g.,
erosion, runoff or leaching risks) of the PI would be appropriate.
• Long-term effects of alum use.
• Continue to investigate a broad array of solutions to the nutrient surplus problem.
• Further analysis of the scientific validity of the PI.
• Overall effectiveness in treating phosphorous problems.
• Capacity to implement phosphorus management programs.
• Monitoring results.
• Understanding economics related to the PI.
• How soil phosphorus levels change as phosphorus-based nutrient management
takes place.
11
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-------
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Recommendations for Coordinating
Phosphorus-Based Nutrient Management
in the Chesapeake Bay Region
Developed by the Agriculture Nutrient Management Workgroup of the
Chesapeake Bay Program's Nutrient Subcommittee
Membership
Doug Goodlander, Pennsylvania State Conservation Commission
Jerry Griswold, NRCS with the Chesapeake Bay Program
Tom Juengst, Pennsylvania Department of Environmental Protection
Russ Perkinson, Virginia Department of Conservation and Recreation
F. Fred Samadini, Chair, Maryland Department of Agriculture
Randy Shank, Virginia Cooperative Extension
Julie Trask, Chesapeake Bay Program
Ron Wood, Virginia Chesapeake Bay Local Assistance Department
Contributors to the Report
Doug Beegle, Penn State University
Greg Binford, University of Delaware
Frank Coale, University of Maryland
Louise Lawrence, Maryland Department of Agriculture
Greg Mullins, Virginia Tech
Jim Pease, Virginia Tech
Jennifer Weld, Penn State University
Facilitators
Phil Favero, University of Maryland
Victor Tervala, University of Maryland
Information pM52)
1650 Arch Street v
-------
INTRODUCTION
Recently, the Chesapeake Bay Program, the Natural Resource Conservation Service
(NRCS) and the scientific community have begun to place a greater emphasis on the role
phosphorus plays in nonpoint source1 pollution. This increased awareness of the risks of
excess phosphorus in the soil profile and its relationship to water quality has led to NRCS
guidance and Environmental Protection Agency-proposed regulations. These proposed
EPA regulations would require operators to implement nutrient control practices for
nitrogen and phosphorus in their farm nutrient management plans for confined animal
feeding operations (CAFOs). Nutrient control practices for nitrogen and phosphorus will
likely become a requirement for farms that meet certain federal criteria. Also, other
federal or state programs may require new practices with respect to phosphorus. For
farming operations that use only commercial fertilizers, this shift should not be
burdensome. However, due to the ratio of phosphorus to nitrogen in animal wastes and
biosolids, phosphorus-based nutrient management planning may be a more arduous task
for livestock and poultry operations as well as for permitted sewage sludge applications.
In addition to the nutrient content of manures, the economics of farming encourages
farmers to apply animal wastes based on nitrogen needs of the desired crop. These two
factors have led to the over-application of phosphorus, which in turn has resulted in
phosphorus-enriched soils in certain locations.
PHOSPHORUS-BASED NUTRIENT
MANAGEMENT-PLANNING WORKSHOP AND QUESTIONNAIRE
The Agriculture Nutrient Reduction Workgroup of the Chesapeake Bay Program's
Nutrient Subcommittee held a one-day conference on "Coordinating Phosphorus-Based
Nutrient Management Policies in the Chesapeake Bay Region" on March 29, 2001.
Agronomic scientists and program implementation staff came together and presented
information on phosphorus management in agricultural systems. The objective of the
conference was to begin building consensus concerning questions and issues pertaining to
phosphorus-based (P-based) nutrient management policies within the region.
Several weeks after the conference, the workgroup distributed a questionnaire to all
participants following up on a formal discussion at the end of the conference. The
follow-up discussion focused on remaining issues and the use of a phosphorus index.
(See Appendix 1 for a summary of the questionnaire and results.) The original workshop
focused on the current science and implementation of phosphorus management, and the
participants were selected accordingly.
'Nonpoint Source Pollution: A diffuse source of pollution that cannot be attributed to a clearly identifiable,
specific physical location or a defined discharge channel. This includes nutrients that runoff the ground
from any land use - croplands, feedlots, lawns, parking lots, streets, forests, etc. - and enter waterways. It
also includes nutrients that enter through air pollution, groundwater or from septic systems.
http:/7 www.chesapeakebay.net/committee.htm.
-------
PHOSPHORUS-BASED NUTRIENT MANAGEMENT PLANS:
THREE FEDERAL MANAGEMENT OPTIONS
NRCS guidelines and proposed EPA regulations would require states to use one of the
following three methods to develop phosphorus-based nutrient management plans for
recipients of NRCS technical and financial assistance or for those operations that fall
under the requirement to obtain animal waste permits.2
(1) Soil Test Phosphorus (STP)
When STP levels are used, phosphorus may be applied at rates consistent with the
following: If the STP level is low or medium, plans can be nitrogen-based. If the
STP level is high, very high or excessive, plans will be phosphorus-based. For
example, a high test level could allow phosphorus application based on crop
removal, and an excessive test level would not allow any phosphorus application.
(2) Soil Phosphorus Threshold Level (PTH)
When soil-specific phosphorus threshold values are available, phosphorus may be
applied at rates consistent with the following: If a soil test is less than 3A PTH,
plans can be nitrogen-based. If the STP is equal or greater than 3A PTH and less
than 1 1/2 PTH, phosphorus can be applied at the level of crop removal. If the soil
test phosphorus is equal or greater than 1 '/2 PTH and less than 2 PTH, phosphorus
can be applied at 1A the level of crop removal. If the soil test phosphorus is equal
or greater then 2 PTH, no phosphorus can be applied.
(3) Phosphorus Index (PI)
When the PI is used, phosphorus may be applied at rates consistent with the
following. If the PI rating is low or medium risk, the plan can be nitrogen-based.
If the PI rating is high risk, phosphorus can be applied at the crop removal level.
If the PI rating is very high risk, phosphorus cannot be applied. (Some
jurisdictions refer to the PI as the Phosphorus Site Index, or PSI.)
A fourth alternative not addressed in NRCS guidance is a combination of any previously
mentioned options. For example, use of Soil PTH to determine if a PI needs to be used.
WORKGROUP ISSUES
In deciding which method to recommend, the individuals polled had to consider many
variables, for example, ease of administration, political feasibility, regional flexibility and
scientific validity, among others. Of those that responded, 60 percent recommended that
the Bay region states adopt the use of the PI. Of the 40 percent that did not pick the PI, 30
percent picked a combination of methods and 10 percent picked STP or the Phosphorous
Threshold. Eighty percent believed that if a PI is adopted for use, a simplified screening
tool, based on a limited number of inputs such as soil test and slope, should be used to
determine whether a detailed PI value must be calculated for the field. Key advantages of
a PI include: state-to-state flexibility, a balanced approach to protecting the environment
2 NRCS: www.nhq.nrcs.usda.gov/BCS/nutri/gm-190.html
-------
that would take into consideration farming constraints, and a consideration of all
parameters that affect water quality. While the majority of those responding chose the
use of a PI, it was also recognized that such a choice has its pitfalls.
Major concerns regarding the use of PI were the complexity and the feasibility of
performing it on every field or management unit. Of those responding, 78 percent
concurred that states should have the flexibility to incorporate a "screening tool" within
the PI, which should make its field use more practical. One probable such tool is STP.
The PI could be calculated for those sites that exceed a predetermined value of the
screening tool used. Other possible screening tools could include the amount of soil
erosion and the proximity to surface water.
The participants were asked to what degree of specificity the input data should be
gathered for the more subjective components of a PI, for example, field slope, soil
permeability, distance to stream, etc. Fifty percent of the respondents suggested that the
use of existing data sets, such as soil surveys, should be used to the maximum extent
practical. The remaining respondents were concerned about the validity of using such
broad data, adding that proper nutrient management planning requires a field visit during
which the necessary data is collected.
The workgroup also discussed the use of "caps" on each individual component of the PI.
A cap is a level of a particular PI element that, when reached by the single element of the
index, places that field or management unit into the highest level of phosphorus
restrictions, regardless of the level of the other PI parameters documented for that factor.
The group concluded that more study is needed to determine if caps on individual
components (e.g. erosion, runoff or leaching risks) of the PI would be beneficial to the
process.
The survey also centered on the bioavailability of phosphorus in the soil and the
subsequent risk to loss via biological and physical pathways. Specifically, should the
various forms of phosphorus (organic and inorganic) be weighted in the PI? The
respondents concluded that further analysis is needed to quantify the effects of various
forms of phosphorus on water quality. Regarding the use of aluminum sulfate (alum), the
general consensus was that because of the many questions associated with the use of
alum (such as the potential for aluminum toxicity); a credit for alum use should not be
considered at this time. Again, further work is needed to assess the long-term benefits and
risks of alum use.
See Appendix 2 for a list of potential information gaps and research needs identified by
the workshop and survey results.
MOVING SURVEY RESULTS INTO RECOMMENDATIONS
Results of the questionnaire were reviewed at a September 13, 2001 follow-up meeting
(see Page 3 for list of attendees). From that meeting, the results of the questionnaire were
evaluated and a list of recommendations developed for consideration by the Chesapeake
Bay Program's Nutrient Subcommittee. The recommendations were developed based on
consensus. Consensus was defined as a decision that everyone could support. The
-------
Agricultural Nutrient Reduction Workgroup prepared the following summary of the
recommendations from that meeting. The survey and the survey results are also included.
RECOMMENDATIONS FOR PHOSPHORUS MANAGEMENT
IN THE CHESAPEAKE BAY REGION
The Chesapeake Bay Program should consider the following recommendations when
promoting phosphorus management within the Bay watershed:
1. States should consider adopting a PI approach as the basis for the phosphorus
component of their nutrient management planning. The PI may incorporate a screening
tool in the nutrient management planning process (where the site exceeds a
predetermined screening tool value).
2. Implementation of the PI should be simplified as much as possible while still
maintaining technical credibility by using existing data sets, such as the use of soil survey
map units to determine the average slope of each site.
3. Sensitivity analysis concerning the effects of various forms of phosphorus (e.g.,
ortho, organic or insoluble particulate phosphorus) on Bay water quality should be
performed as a basis for individual weights for the forms of phosphorus within the index.
4. The benefits of placing caps on individual components of the PI should be based on
existing and future research. Caps could be placed on relevant components of the PI (for
example, those that exceed certain soil test or erosion levels) that would automatically
require full PI analysis.
5. There is a nutrient imbalance in the Chesapeake Bay region. The PI is a tool to assist
farmers and nutrient management planners in prioritizing the application of animal
wastes to minimize the impact of the current imbalance, but in itself the PI is not a
solution to the nutrient surplus in the Bay region. The members of this group and the
Chesapeake Bay Program should continue to investigate a broad array of solutions to the
nutrient surplus problem.
-------
APPENDIX I
QUESTIONNAIRE RESULTS SUMMARY
Question 1: What assistance is needed to implement P-based nutrient management
planning in your area?
General Responses: Education, financial assistance for manure transport, other off-farm
uses, value-added processing and marketing. Planning and research where applicable is
also needed.
Question 2: NRCS guidance and proposed EPA regulations would require states to use
one of three methods to develop phosphorus-based nutrient management plans for
permits. Which of the following methods should be adopted by states in the region: A.
STP Level; B. Threshold; C. PI; or D. a combination of the above?
Question 3: If a PI is adopted, should a simplified screening tool based on a very limited
number of inputs such as soil test phosphorus and slope be used to determine if a detailed
PI value needs to be calculated?
Related Considerations Provided for Question 3:
1. Ease of implementation.
2. Ability to exclude areas that do not contribute to the phosphorus problem.
3. Discriminating quality of the method used.
4. Political feasibility: citizens, producers and political representatives.
5. Scientific validity.
6. Overall effectiveness in treating the problem.
7. Prior experience in using the method (education).
8. Includes the ability to evaluate or measure the transport potential.
9. Accounts for all factors affecting P export from agricultural lands.
10. Site specific.
11. Flexible instrument.
12. Provides management options for producers.
13. Serves as an educational tool.
14. Impact on producers' burden.
15. Possess the technical capacity to implement.
16. Ease of monitoring outcome.
17. Allows phosphorus application at replacement rate.
18. Cost to landowners.
Final recommendation for questions 2 and 3: We recommend the adoption of a PI as
the basis for the phosphorus component of nutrient management planning. The PI may
incorporate a screening tool as an integral element of the nutrient management planning
process.
Question 4: If a screening tool is adopted, should the method: A. Require a PI to be
calculated for all sites that exceed a predetermined value of the screening level; B.)
-------
Require a PI to be calculated for all sites below a predetermined value of the screening
level; or C.) a combination of the above?
Final Recommendation: If a screening tool is adopted, the complete PI should be
calculated for all sites that exceed a predetermined screening tool value(s).
Question 5: Inorganic, water-soluble forms of phosphorus are immediately available to
aquatic plants, while particulate phosphorus associated with sediment or organic matter
becomes available slowly, over time. Both forms are lost to surface waters. How should
particulate phosphorus be weighted relative to inorganic water-soluble phosphorus losses
in a PI?
Final Recommendation: Consideration of the relative weighting of the various forms of
phosphorus should be based on the short- and long-term impact of each form on water
quality.
Question 6: Should there be caps on individual components of the PI?
Final Recommendation: The consideration of caps on individual components of the PI
should be based on existing or future research. Possible caps could include soil test
phosphorus level, erosion loss and fertilizer/manure phosphorus loading rates.
Question 7: Concerning the level of complexity of data input for a PI, what process
should be adopted in the Chesapeake Bay region—detailed field data collection vs. use of
existing data sets and proxies?
Final Recommendation: Collect and assess data onsite and use existing data sets where
relationships have been established.
Question 8: Should alum use be given credit in phosphorus-based nutrient management
plans?
Final Recommendation: There is promising research that could qualify the use of alum,
but researchers are not able to answer this question at the present time. More study of the
long-term affects and use of alum is needed.
Question 9: A previously unmanured site that tests medium in soil test phosphorus is
being considered for a new swine operation. A PI is calculated to arrive at a moderate
risk. However, once soil test phosphorus levels reach 280 ppm phosphorus for this site,
the PI will be very high, indicating that no further phosphorus applications are
recommended. If you are the permit issuing authority, what should you do?
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Final Recommendation: Farmers should be advised of their options and the
consequences of every action. Ultimately this is a business decision made in relation to
program and permit requirements. The permit issuing authority needs to educate the
farmer in all the implications of the law.
Question 10: If phosphorus-based nutrient management planning identifies a surplus of
manure for a given farming operation, what policy should be put in place to deal with the
exported manure?
General Responses: Financial assistance for manure transport. Keep manure in the state
where it is generated. A nutrient management plan should be required for receiving
farms. Rely on the market value approach. Use a phosphorus screening tool and run the
PI on the receiving farm. Soil test the receiving farm. Nitrogen- and phosphorus-based
plans - all users of fertilizer should be treated equally.
Question 11: Do you think the use of a PI will improve water quality?
General Responses: The bulk of the responses supported use of the PI for improving
water quality. The detailed comments stated that the PI is currently the best method to
achieve P reductions, but monitoring and efficient implementation is needed. The water
quality effects of the PI were not discussed extensively in follow-up discussions.
Question 12: What other suggestions or questions do you have pertaining to
implementation of phosphorus-based nutrient management policies in the Chesapeake
Bay region?
General Responses: We need to educate citizens and farmers, and to promote research
and monitoring; other tools need to be explored as well, such as dietary changes.
Consider the remediation and redistribution of manure. We need more education and
technical training, and to understand the economics of phosphorus-based nutrient
management planning. In addition, there should be uniformity on phosphorus-based
planning among the states. Nutrient balances should be completed county-by-county for
all sources. We need to understand overtime how soil phosphorus levels change as
phosphorus-based nutrient management takes place.
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APPENDIX II
INFORMATION AND RESEARCH NEEDS
RELATED TO THE PHOSPHORUS INDEX
The following items are extracted from the report text and questionnaire results:
• The complexity and the feasibility of performing the PI on a large number of
fields or management units.
• The validity of using existing reference data sets compared to onsite collected
data.
• More study is needed to determine if "caps" on individual components (e.g.,
erosion, runoff or leaching risks) of the PI would be appropriate.
• Long-term effects of alum use.
• Continue to investigate a broad array of solutions to the nutrient surplus problem.
• Further analysis of the scientific validity of the PI.
• Overall effectiveness in treating phosphorous problems.
• Capacity to implement phosphorus management programs.
• Monitoring results.
• Understanding economics related to the PI.
• How soil phosphorus levels change as phosphorus-based nutrient management
takes place.
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