1 / 33

L. Bundy, L.W. Good, P Kaarakka, W. Jarrell University of Wisconsin-Madison

Nutrient management tools for protecting environmental quality while maintaining economic sustainability: Tools that meet a regulatory requirement – The Wisconsin P Index L. Bundy, L.W. Good, P Kaarakka, W. Jarrell University of Wisconsin-Madison The Wisconsin P Index Structure of P index

lotus
Télécharger la présentation

L. Bundy, L.W. Good, P Kaarakka, W. Jarrell University of Wisconsin-Madison

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. Nutrient management tools for protecting environmental quality while maintaining economic sustainability:Tools that meet a regulatory requirement – The Wisconsin P Index L. Bundy, L.W. Good, P Kaarakka, W. Jarrell University of Wisconsin-Madison

  2. The Wisconsin P Index • Structure of P index • Research basis for P index estimates of P loss • Application of P index

  3. The Wisconsin P Index • Indicates potential of a field to deliver P to surface water • P index values used to rank fields for P loss • Identifies management options for reducing P loss

  4. Where does the P Index fit in nutrient management planning?

  5. The P Index and Nutrient Management Planning • Tool for implementing P-based planning • Options for P applications: • Use Wisconsin P index • Rates based on soil test P values

  6. Components of the Phosphorus Index (PI): PI = PP + SP PI =Total P index PP =Particulate P SP =Soluble P

  7. Sediment delivered to edge of field calculated by RUSLE2 Assumes no concentrated flow in field, but includes effects of in-field deposition if multiple field slope or management segments are entered in the program. Field Delivery point for P Index calculation: perennial or intermittent stream Sediment travels via concentrated flow from edge of field to waterway Particulate P Movement Particulate P = Sediment loss x Sediment P concentration x Sediment delivery ratio

  8. Dissolved P Movement Soluble P = Annual runoff volume x Dissolved P concentration Dissolved P delivered to edge of field calculated as annual rainfall plus snowmelt runoff volume times the average runoff P concentration Field No off-field infiltration. Volume of runoff and concentration of P in the runoff does not change with distance to delivery point. Delivery point for P Index calculation: perennial or intermittent stream

  9. Wisconsin Datasets used for P Index Development • Simulated rainfall runoff: • Alfalfa – 20 events • Corn – 267 events, 4 sites Varying: • Tillage • Manure applications • Timing • Soil test P

  10. Natural rainfall runoff: • Alfalfa – 24 plots • Corn- 36 plots Research ongoing. Datasets growing.

  11. Soil hydrol. group Field slope (%) Soil group Contour, Terrace, Residue Mgt. Crop Distance (Field to H2O) & Ave. Dist. slope (%) Erosion rate Bray P-1 soil test Manure rate & type Avail. P2O5 Month of manure application Fert. Rate, P2O5 % Incorporated (X) Frozen ground (X) Parameters needed to calculate P index values

  12. The Interpretation of the Wisconsin PI - field basis 0 - 2: Minimal risk, N-based management 2 - 6: PI should not increase over 4 years or length of average rotation 6 -10: Implement plans to decrease PI to <6 over two rotations (max. 6 years) > 10: Lower PI to <10 over one rotation or 4 years, anddecrease PI to <6 over two additional rotations or 6 years

  13. PP = Annual mass loss x sediment P concentration SP = Annual volume loss x runoff P concentration

  14. Soil water soluble P can be predicted from soil test P

  15. Runoff dissolved P can be predicted by soil test P and soil type Simulated rainfall runoff corn plots without manure applications

  16. Simulated rainfall runoff corn plots four to six months after incorporated manure

  17. New P additions to a field can be accounted for in P Index calculations adjusting soil test P concentrations used in dissolved P concentration calculations

  18. Natural runoff results show average runoff dissolved P concentrations related to soil test P

  19. Relationship between average runoff dissolved P concentrations and soil test P on corn plots at Arlington, April through July, two soils, varying manure history and tillage

  20. Particulate P concentrations can be predicted with soil test P PP concentration = STP x Enrichment ratio

  21. Relationship between soil test P and total P for soils from simulated rainfall runoff plots from three sites

  22. Enrichment ratio = Sediment P/Soil Total P

  23. Sediment P enrichment ratio for simulated rainfall runoff plot events No enrichment for simulated and natural runoff from corn!

  24. PP = Annual mass loss x sediment P concentration SP = Annual volume lossx runoff P concentration Concentrations are only half of the story! P Index web site http://wpindex.soils.wisc.edu/ has more information

  25. Single-event worst-case losses from surface manure applications are added to estimated annual P delivery

  26. Risks of manure P loss change by season of application: • Fall • Spring • Winter (frozen soil)

  27. Runoff dissolved P and particulate P from simulated rainfall event one week after a 32 ton per acre dairy manure surface applicationto silt loam soil in the Spring (Lancaster) and Fall (Arlington) 

  28. The additional SP load from • Spring manure = 0.5 % • Fall manure = 3.7 % • of the manure water soluble P. • The additional PP load from • Spring manure = 0 • Fall manure = 2.9 % • of the manure total P.

  29. Putting it all together: The P Index shows the relative effects of different field management practices on P loads

  30. Improved management practices to decrease PI if values are too high Lower Bray PI (see above for particulate P) Low-disturbance manure incorporation Eliminate mineral P supplements Soluble P too high Decrease soluble P in manure Chemically sorb or precipitate P Change winter spreading Storage Spread on low-risk sites

  31. P Index Values for Grant County Corn Field Rozetta silt loam soil, 6% slope, Bray P 50 ppm 7 6 Winter Manure Fall Manure Winter Manure 5 No Manure 4 Fall Manure Spring Manure P Index 3 Spring Manure No Manure 2 1 0 Chisel Plow No - till Particulate P Soluble P

  32. The P Index and Nutrient Management Planning • P index is not the ultimate solution to nutrient management • Balancing nutrient inputs and removals is the ultimate goal • Using the P index can minimize environmental problems until balance is achieved

  33. SNAP-Plus Output: Field by field fertilizer and manure application plan, P Index value, soil loss estimate Nutrient application calculator Entry: Field by field crop manage-ment info P Index calculator RUSLE2 soil loss calculator The SNAP-Plus program will produce field-by-field nutrient management plans that will meet the 590 Nutrient Management Standard with a P Index value and soil loss estimate for each field

More Related