What The Revised P Index Will Look Like - Libby Dayton, from the 2018 Conservation Tillage and Technology Conference, March 6 - 7, Ada, OH, USA. More presentations at https://www.youtube.com/channel/UCZBwPfKdlk4SB63zZy16kyA

1. On-Field Ohio !
Evaluate/Revise the Ohio P Risk Index
using
Field-Scale Edge-of-Field Monitoring Data
Dr. Elizabeth (Libby) Dayton, Shane Whitacre, Dr. Chris Holloman,
Dr. Kim Love,

2. 2
Revised Conservation Practice Standard
Nutrient Management, Code 590
USDA-NRCS-Ohio
Increased Emphasis on
Ohio P Risk Index
which includes
Tri-State Fertilizer Recommendations
4Rs, Nutrient Stewardship
On-Field Ohio!

3. 3
On-Field Ohio!
OSU / USDA-NRCS
Long-term, Field-Scale Average Estimate of
Erosion Potential and P Runoff Risk
Quantifies how voluntary changes
in practices contributes to target P
runoff reduction goals

4. 4
• Introduction
• Findings
• On-Line Tool
• Across Ohio
Agenda
On-Field Ohio!

5. 5
Evaluate Relationship Between
On-Field Properties & Practices
& Edge-of-Field P Runoff
Special Thanks to
Participating Farmers29 Study Fields

6. 6
What Did We Measure?
Surface & Tile P Runoff Concentration
Dissolved (DRP)
filtered
Particulate
(RPP)
Total (RTP)
unfiltered/digested
Runoff Flow Volume
On-Field Ohio!

7. 7
Every Runoff Event
Surface & Tile Runoff:
• DRP Dissolved P
• RPP Particulate P
• RTP Total P
• RSS Suspended Sediment
• Runoff Flow Volume
Erosion Potential
• Each CY and Rot. Avg
Annual Soil Test P (M3-P)
On-Field Ohio!
Annual Farmer Management

8. 8
Erosion Potential
Revised Universal Soil Loss Equation v2
(RUSLE2)
Soil Loss (t/a/y)
Related to
RSS & RPP
Muddy Runoff Water
• How much sediment?
• How rich in P is sediment?
On-Field Ohio!

9. 9
Revising Ohio P Risk Index
Process:
• Establish equations to estimate runoff P
• Additional P runoff risk due to fert/man. App.
• Provide users unambiguous results
Empirical relationships based on EOF data
Tailoring APLE* using EOF data
Measured EOF vs OFO Estimates
*APLE = Annual Phosphorus Loss Estimator (Peter Vadas, USDA-ARS)
On-Field Ohio!
Correlating
Edge-of-Field Runoff Results
With
On-Field Properties and
Practices

10. 10
Agronomic
Range
On-Field Ohio!
Study Fields
M3-P(0-8",ppm)
0
50
100
150
200
250
300
350
400
450
Agronomic
Range
On-Field Ohio!

11. 11
DRPb vs Mehlich3-P, Avg. across Yrs
DRPb = 0.003(M3-P, 0-8") + 0.055, r2
= 0.94****
DRPb = 0.0032(M3-P, 0-2") - 0.004, r2
= 0.95****
Mehlich3-P (STP, mg/kg)
0 50 100 150 200 250 300 350 400
RunoffDissolvedP(DRP,mg/L)
0.0
0.2
0.4
0.6
0.8
1.0
1.2
1.4
M3-P, 0-8"
M3-P, 0-2"
Surface DRP vs M3-P 0-8” & 0-2”
On-Field Ohio!

12. 12
Surface DRP Runoff Load
Meas. DRP = 0.93(Estimated) - 0.07, r
2
= 0.904****
Ln Estimated DRP (lb P/A)
-7 -6 -5 -4 -3 -2 -1 0 1
LnMeasuredEOFDRP(lbP/A)
-6
-5
-4
-3
-2
-1
0
1
2
On-Field Ohio!
Measured vs Estimated Surface Runoff DRP (lb/A)
On-Field Ohio! Estimated
Edge-of-FieldMeasured

13. 13
B. Ln EOF vs Ln OFO/APLE RPP (lb/A)
LnEOF = 0.92(LnOFO/APLE) - 0.7, r
2
= 0.83****
Ln OFO/APLE RPP (lb/A)
-6 -4 -2 0 2 4
LnEOFRPP(ppm)
-6
-4
-2
0
2
Measured vs Estimated Surface RPP (lb/A)
Using Rotation Avg. Erosion
On-Field Ohio!

14. 14
B. Ln EOF vs Ln OFO/APLE RTP (lb/A)
LnEOF = 0.92(LnOFO/APLE) - 0.44, r2
= 0.89****
Ln OFO/APLE RTP (lb/A)
-4 -3 -2 -1 0 1 2 3
LnEOFRTP(lb/A)
-4
-3
-2
-1
0
1
2
Measured vs Estimated Surface RTP (lb/A)
Using Rotation Avg. Erosion
On-Field Ohio!

15. 15
Measured vs Estimated DRP & RTP (ppm)
Meas. DRP = 1.03(esti.) - 0.001, r2 = 0.94****
Meas. RTP = 1.09(esti.) + 0.003, r2 = 0.84****
Estimated (ppm)
0.0 0.5 1.0 1.5 2.0 2.5 3.0
Measured(ppm)
0
1
2
3
RTP
DRP
On-Field Ohio!
Measured vs Estimated Tile DRP & RTP (ppm)

16. 16
Tile, Measured vs Estimated (lb/A)
Ln EOF DRP = 1.01(Ln esti.) + 0.04, r
2
= 0.73****
Ln EOF RTP = 1.06(Ln esti.) + 0.12, r2
= 0.77****
Tile Ln OFO Estimated P Load (lb/A)
-4 -3 -2 -1 0 1
TileLnMeasuredEOFPLoad(lb/A)
-5
-4
-3
-2
-1
0
1
2
DRP
RTP
Measured vs Estimated Tile DRP & RTP (lb/A)
On-Field Ohio!

17. 17
Coming Soon
On-Field Ohio!
On-line Calculator
Using:
RUSLE2 plus
Developed Equations
• Erosion (t/a/y)
• Surface & Tile (lb/A)
DRP & RPP
Fertilizer/Manure
additional DRP (lb/A)
• Save, Print Report

18. 18
On-Field Ohio!
Tool Functions
Find New Field or Import a Stored Field

19. 19
Google Map Tool
Map or Satellite
mode
Search by
City/Town
Address
Zip code
eyeball

20. 20
Field information
Map Unit (Legend)
Soil survey data
Area
Climate
CMZ
Assign
Field Name

21. 21
Crop Year
Nov. 1
to
Oct. 31
Start w/ CMS template
Amend as needed
Tool runs RUSLE2 Erosion Program

22. 22
Field Drainage
• Yes/No
Soil Organic Matter
• Default/measured value
Soil Test P
• Mehlich3-P ppm
• Tool can convert from
Bray and other units
User Provides
Field Specific Information

23. 23
Planned: Solid/Liquid Manure, Fertilizer
When? Amount P2O5? Placement Method?
4Rs

24. 24
Results
Each CY & Rotation Avg., Download Report

25. 25
Demonstrate How
Voluntary Practices
Achieve Target Reduction
On-Field Ohio!
Results
Example

26. 26
2 crop management scenarios (CMS A & B)
A: Fall chisel, spring disk & field cultivate
corn, no-till beans
B: No-till corn, no-till beans
3 Soil test P (15, 50, 150 mg/kg, Mehlich3-P)
Power of Comparison
Example: Blount Silt Loam with 2 – 4% Slope
Compare rotation average On-Field Ohio! results for
corn/bean rotations across:
On-Field Ohio!

27. 27
CMS A B A B A B
Soil Test P (mg/kg) 15 50 150
Erosion (t/a/yr) 2.2 0.43 2.2 0.43 2.2 0.43
Runoff P Loss (lb P/acre)
Surface Particulate 1.12 0.32 1.69 0.49 2.90 0.84
Tile Particulate 0.16 0.16 0.21 0.21 0.37 0.37
Surface Dissolved 0.05 0.04 0.15 0.12 0.46 0.36
Tile Dissolved 0.04 0.04 0.08 0.08 0.29 0.29
Total P Loss 1.4 0.56 2.1 0.90 4.0 1.9
On-Field Ohio!
80.5% Reduction in erosion
71% Reduction in Surface RPP
STP Increase 15 to 150 mg/kg increase:
Tile: >2x particulate P, >7x dissolved P
Surface: >9x dissolved P

28. 28
Accounts for 4Rs
• Time, Source, Amount & Placement Method
Availability for P to Runoff
• Assumes Portion of P is water extractable (WEP)
• Assumes portion not WEP can mineralize to WEP
• Liquid (<15% solid) assume 60% of P infiltrates
• Tool estimates WEP or can use measured value
Placement Method
• Portion of liquid that does not infiltrate or was not
incorporated is vulnerable to runoff
• Incorporation directly related to runoff risk reduction
Manure Land Application Specifics
On-Field Ohio!
*APLE = Annual Phosphorus Loss Estimator (Peter Vadas, USDA-ARS)

29. 29
Solid Liquid
P2O5 Applied lb/A 100 100 100 100
% solids 60 60 10 10
% WEP 35 35 35 35
% Incorporation 0 90 0 90
P Runoff lb/A 1.17 0.12 0.3 0.03
Example
Solid vs. Liquid, Surface vs Incorporated
On-Field Ohio!

30. 30
How is Ohio Doing?

31. 31
Statewide Simulations
P Index Tool Equations
Assign CMS
Assign STP
Criteria Tile Yes/No
>6000 Point Locations
STP, Random Selection
Thanks to Survey:
A&L Great Lakes Labs
Brookside Labs
Spectrum Analytic
On-Field Ohio!

32. 32
Statewide
M3P
STP (ppm)
Range
3 to 1011 ppm
Mirrors Ohio
Soil Test Lab
Data Survey

33. 33
Test Simulations of Erosion
Compare Crop Management Scenarios (CMSs)
Across
Full range Soil Tillage Intensity Rating (STIR, 0 - 100)
CMS STIR CMS
1 2.6 No-Till CY1, No-Till CY2
2 7.8 Vertical Tillage Fall CY1
No-Till CY2
3 38.3 Rotational Tillage, Chisel Fall CY1
Spring Cultivate CY2
4 93.6 Spring Chisel/Cultivator, Fall Moldboard
plow CY1 Spring disk/cultivate CY2
On-Field Ohio!

34. 34
A. CY1 Erosion (t/a/y), across CMSs
Range: 0.004 to 15.8, Med: 0.42 (t/a/y)
0 2 4 6 8
Count
0
1000
2000
3000
4000
5000
6000
B. CY2 Erosion (t/a/y), across CMSs
Range: 0.007 to 31.4, Med: 0.91 (t/a/y)
Erosion (t/a/y)
0 1 2 3 4 5 6 7 8
Count
0
1000
2000
3000
4000
5000
6000
Erosion Across all CMSs/Point Locations
On-Field Ohio!

35. 35
Erosion (t/a/y)
<0.25
>0.25 to 0.8
>0.8 to 2
>2 to 4
>4
CMS1
CMS4CMS3
CMS2
RUSLE2
Erosion
(t/a/y)

36. 36
A. Surf. Runoff Dissolved P (DRP, lb/A)
Range: 0.008 to 5.5 lb/A
Med: 0.13 lb/A
Count
0
1000
2000
3000
4000
B. Surf. Runoff Particulate Bound P (RPP, lb/A)
Range: 0.023 to 64.5 lb/A
Med: 1.15 lb/A
0.0 0.5 1.0 1.5 2.0 2.5 3.0 3.5 4.0 4.5
Count
0
1000
2000
3000
4000
5000
Surface Load
On-Field Ohio!NOTE
RPP ≈ 10x > DRP

37. 37
A. Tile Runoff Dissolved P (DRP, lb/A)
Range: 0.037 to 8.28 (lb/A)
Med: 0.077 (lb/A)
Count
0
2000
4000
6000
B. Tile Runoff Particulate P (RPP, lb/A)
Range: 0.180 to 3.11
Med: 0.234
0.0 0.2 0.4 0.6 0.8 1.0
Count
0
500
1000
1500
2000
2500
3000
Tile Load
On-Field Ohio!NOTE
RPP ≈ 3x > DRP

38. 38
Surf. + Tile Runoff Total P (RTP, lb/A)
Rotation Avg. Erosion
Range: 0.0 9 to 70, Med: 1.6
S+T RTP (lb/A)
0 1 2 3 4 5 6 7 8 9 10
Count
0
1000
2000
3000
4000
Surface + Tile RTP Load
On-Field Ohio!

39. 39
• Need to REDUCE P load to Ohio surface waters
•Reduce Erosion
•Reduce Soil P Levels
Conclusions
BIG MOVE From Qualitative to Quantitative
for Ohio P Risk Index
• Increasingly Used to Judge Farmer Performance
So We Have to Get it Right !
• Comparisons of CMSs allow farmers to prioritize
time and resources in effective management
decisions
On-Field Ohio!

40. 40
Thank you
Questions???
On-Field Ohio!