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User capabilities and next generation phosphorus (p) indices

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Full proceedings available at: http://www.extension.org/72814

The phosphorus (P) index is the primary approach to identify field management strategies and/or manure application strategies likely to lead to excessive risk of P loss. It has been over 40 years since the first research connecting agronomic P management and water quality and over 20 years since the initial publication defining a P Index. This session will consider opportunities to build on and expand existing P Index strategies to make them more effective at protecting water quality and friendlier to the target user.

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User capabilities and next generation phosphorus (p) indices

  1. 1. User Capabilities and Next Generation Phosphorus Indices Waste to Worth April 2, 2015 John A. Lory University of Missouri Nathan O. Nelson Kansas State University
  2. 2. Timeline of P Management Tools Initial use of chemical extracts to predict crop response to fertilizers (Anderson, 1960). Development of current soil test phosphorus extracts for agronomic assessment (Bundy et al., 2005). Initiation of the environmental assessment era. Resource Assessment 1850 1900 1940 1985 2014
  3. 3. Timeline of P Management Tools Initial research connecting soil test P to runoff water quality (e.g. Romkens and Nelson, 1974; Sharpley et al. 1977; 1978). Initial P Index framework (Lemunyon and Gilbert, 1993). EPA-NRCS Unified national strategy for CAFO’s calling for P loss assessment on agricultural fields. CAFO rule requiring P loss assessment for regulated applications. Environmental Assessment 1970 1994 1999 2008 2014
  4. 4. Apple Pie Effect The term “P Index” has come to mean different things in different places... …but the differences are not always appreciated because all are called “P Indices”. We have an opportunity sharpen our approach to P loss assessment.
  5. 5. Opportunities as we Re-consider P Loss Assessment Tools • Regional approach. • Focus on the user’s capabilities. • Clarify water quality goal. • Clarify temporal context of each P Index. – Multiple tools to solve multiple challenges? • Tools that promote voluntary adoption. • Tools with applicability beyond manure. We have an opportunity…
  6. 6. Opportunities as we Re-consider P Loss Assessment Tools • Regional approach. • Focus on the user’s capabilities. • Clarify water quality goal. • Clarify temporal context of each P Index. – Multiple tools to solve multiple challenges? • Tools that promote voluntary adoption. • Tools with applicability beyond manure. We have an opportunity…
  7. 7. Soil sampling protocol Fertilizer recommendation source Crop N & P need Manure sampling protocol P loss assessment protocol Nutrient availability coefficients Manure nutrient valueP loss rating Manure application rate Manure rate calculations Manure test results Soil test results Manure application methodTillage Yield goal determination Crop selection Management Options: Green Protocols: Red Outcomes: Black Nutrient Management: A process, not a result.
  8. 8. Thinking About Time NM Plan Soil test result Manure test result P Loss assessment 1-5 year Plan (state dependent) Sample every 3-5 years Annually Annually Annually AnnuallyAnnually <1 to 5-year assessment (state dependent) Future application rate cannot be known… Based on time sensitive information. Therefore – Initial planning is a strategic process: what is feasible? Nutrient Management: A process, not a result.
  9. 9. Strategic planning (1 to 5 years) • Determine long-term goals (strategic goals) and mapping out a strategy to attain those goals. • Feasibility. Tactical planning (1 to 12 months) • Adjustments to strategic plan based on incoming information. – New manure test results. – Changes in cropping system. Implementation (1 to 3 days) • Are conditions today appropriate for P application. Nutrient Management: A process, not a result.
  10. 10. Capabilities of the planner/decision maker – Certified nutrient management planner • Expectation for training and competency in use of complex decision support tools. • Experienced in sophisticated strategic nutrient management planning. – Farmer or farm manager • Familiarity with computers. • Experienced in strategic planning but not necessarily with specifics related to nutrient management. – Contract or professional manure applicator • Uncertain computer skills. • Experienced in short-term tactical assessments and implementation decisions. – Farm worker • Limited computer skills. • Experienced in implementation decisions.
  11. 11. Strategic Planning Tactical Planning Implementation Dedicated Planner Farm Manager Contract Applicator Farm Worker ? ? ? Who is needs to make these decisions? (Who needs to use the tool?) ? ? ? ? ? ? ? ? ?
  12. 12. Strategic Planning Tactical Planning Implementation Dedicated Planner Farm Manager Contract Applicator Farm Worker Yes Yes? No? No Yes YesYes? Yes Yes Yes? No No Who is needs to make these decisions? (Who needs to use the tool?)
  13. 13. P Index Implementation State STP Erosion Rate Application Method? Timing Apparent time step IA Yes RUSLE2 Total P Yes No By year KS Yes RUSLE2 Fertilizer/Manure Yes Yes By year, use highest year (5-yr plan) MO Yes RUSLE2 No No No 5-yr plan MD Yes RUSLE Fertilizer/Manure Yes Yes By year MS Yes RUSLE2 Fertilizer/Manure Yes No By year NC Yes RUSLE/ RUSLE2 Fertilizer/Manure Yes No Based on most erosive in 5-yr plan NY Yes RUSLE2 Fertilizer/Manure Yes Yes By year for 1-yr plan PA Yes RUSLE/ RUSLE2 Fertilizer/Manure Yes Yes By application for 1- yr plan
  14. 14. Examples of P Assessment Tools Existing Approaches Examples Complexity Data Needs Regional Strategic Risk: Which farms? Which fields in a watershed? Watershed models APEX, SWAT, SPARROW High Extensive Nutrient Balance Cornell Whole Farm Nut. Bal. Moderate Moderate Field Strategic/Tactical Risk: Which fields? Which strategies? Changes to my plan? Simplified model Nutrient Tracking Tool High Extensive APLE Moderate Moderate Decision support P Indices Low-Moderate Low-Moderate Implementation Risk: Application today? Decision support WI Runoff Risk Advisory Forecast Low Low BMP List NRCS Nutrient Mgt. Std. Low Low
  15. 15. Strategic Planning Tactical Planning Implementation Dedicated Planner Farm Manager Contract Applicator Farm Worker RUSLE2 Challenge: Often needed for strategic and tactical decisions. Ideally who is makes these decisions?
  16. 16. Opportunities as we Re-consider P Loss Assessment Tools • Regional approach. • Focus on the user’s capabilities. • Clarify water quality goal. • Clarify temporal context of each P Index. – Multiple tools to solve multiple challenges? • Tools that promote voluntary adoption. • Tools with applicability beyond manure. We have an opportunity…
  17. 17. P Index Implementation State STP Erosion Rate Application Method? Timing Apparent time step IA Yes RUSLE2 Total P Yes No By year KS Yes RUSLE2 Fertilizer/Manure Yes Yes By year, use highest year (5-yr plan) MO Yes RUSLE2 No No No 5-yr plan MD Yes RUSLE Fertilizer/Manure Yes Yes By year MS Yes RUSLE2 Fertilizer/Manure Yes No By year NC Yes RUSLE/ RUSLE2 Fertilizer/Manure Yes No Based on most erosive in 5-yr plan NY Yes RUSLE2 Fertilizer/Manure Yes Yes By year for 1-yr plan PA Yes RUSLE/ RUSLE2 Fertilizer/Manure Yes Yes By application for 1-yr plan
  18. 18. Strategic Planning Tactical Planning Implementation Long-term Average Rotational Losses Long-term Annual or Seasonal Losses Seasonal Forecasting Short-term Weather Forecast Your choices have direct implications on how you develop and validate your tools Establish Temporal Context
  19. 19. Event-based loss Long-term average loss by year Long-term average rotational loss 0 1 2 06/27/11 08/17/11 11/10/11 11/27/11 04/06/12 04/15/12 04/30/12 05/02/12 05/05/12 05/07/12 10/24/12 11/12/12 04/09/13 05/21/13 05/28/13 TotalPhosphorus (kgha-1) Measured Simulated Best Judgment Simulated Calibrated Establish a Temporal Context: Some Examples
  20. 20. Agronomic Soil Testing Farm- and field-level Strategic Assessment What fields will respond to phosphorus? What fertilizer rate should I apply to this field? Potential users Farmers Consultants/Ag. advisors
  21. 21. Our Challenge • Clearly define goals as a first step. • Tools must be accessible to those who need to use them. • We are not developing “the P Index”. Our goal is a suite of tools targeted at key decision points. Our tools can be complex – but they must be simple to use.

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