Southern p indicies osmond

D. Osmond (NC), C. Bolster (KY), M. Cabrera (GA), S. Feagley (TX), A. Forsberg (GA), C. Mitchell (AL), A. Mittelstet (NE), R. Mylavarapu (FL), L. Oldham (MS), D. Radcliffe(GA), J. Ramirez‐Avila (MS), A. Sharpley (AR), D. Storm (OK),

F. Walker (TN), and H. Zhang (OK)

Annual Soil & Water Conservation Society MeetingLouisville, KY

July 24‐27, 2016

1. Southern – AL, AR, FL, GA, LA, KY, MS, NC, OK, SC, TN, & TX

2. Chesapeake Bay – DE, NY, PA,VA, & WV

3. Heartland – IA, KS, MO, & NE

4. National synthesis project

Refine and Regionalize Southern Phosphorous Assessment Tools Based on

Validation and State Priorities

TX

OK

FL

AL GA

AR

LA

NC

MS

TN

KY

SC

²0 250 500125 Miles

Albers Equal-Area Conic

Southern States and Types of Phosphorus Indices

A

C

CC

Q

M

A

M

M

MM

M

Comparing Ratings of the Southern P Indices: Prior Work

Southern Phosphorus Indices CIG: Objectives

1. Determine pre‐existing watershed or plot‐scale (11) sites where accuracy of P Indices to estimate site P loss potential can be evaluated.

2. Compare fate and transport models against water quality data from benchmark sites.

3. Compare predictions of P‐Indices to water quality data from benchmark sites.

4. Compare predictions of P Indices against fate and transport water quality models (APEX, TBET, APLE) for calibrated and uncalibrated models.

5. Refine P Indices to ensure better consistency in ratings across state boundaries and within physiographic provinces.

Locations of Benchmark Data Sets for Southern P‐Index Analysis

Southern Field Site InformationState # Plots Date range Site‐years Crop STP range (ppm)

1 2 3 4AR 7 2009 – 2011 21 Pasture 81 ‐ 183 Captina (C)GA 6 1995 – 1998 24 Pasture 14 ‐ 142 Cecil (B) Altavista (C) Sedgefield (C) Helena (C)

NC 5 2011‐2013 15Corn with wheat

cover44‐121 Delanco (C)

MS 2 1996‐1999 8Cotton or soybens with wheat cover

37‐79 Dubbs (B) Tensas (D) Alligator (D) Dundee (C)

OK 1 1972‐1976 4 Cotton 20 McLain (C) Reinach (C)OK 1 2006‐2007 1.17 Pasture 50 Clarksville (B)OK 1 1977‐1992 16 Native grass 15 Bethany (C)OK 1 1980‐1985 6 Wheat 35 Norge (B)TX 1 1998‐2001 4 Hay 435 Duffau (B)TX 1 2005‐2008 4 Sorghum/Oats 34 Topsey (C) Brackett (C) Krum (D)TX 1 2005‐2008 4 Native grass 10 Nuff (C)

TX 1 2001‐2008 7Corn with wheat

cover51 Houston Black (D)

Soil Series (hydro group)

Benchmark Water Quality TP Losses vs Model (APEX, APLE, and TBET) Predictions: Arkansas

Benchmark Field Sites

TP DPDP/

TP RatioAPEX TP

APEX DP

APLE TP

APLE DP

TBET TP

TBET DP

NRCS†P Index Ratingkg ha‐1 yr‐1 % kg ha‐1 yr‐1

AR (Sharpley 2016)

Check 0.10 0.07 0.70 1.15 0.93 0.63 0.49 0.58 0.42 Low

Broadlitter 0.71 0.60 0.85 0.39 0.33 2.90 2.51 1.26 0.42 Low

Injectlitter 0.84 0.76 0.90 0.52 0.49 1.40 0.84 1.67 0.51 Low

Injectlitterx2 0.87 0.79 0.91 0.94 0.91 1.37 1.04 0.99 0.45 Low

RotGraz+litter 2.12 1.72 0.81 0.69 0.63 4.71 4.56 1.44 1.24 LowConGraz+litter 1.52 1.41 0.93 0.42 0.39 5.61 5.43 2.70 2.39 Low

Hay+litter 1.50 1.29 0.86 0.07 0.01 5.46 4.74 2.39 0.96 Low

† NRCS ranking equivalencies Low (< 2.2 kg ha‐1), Moderate (2.2 to 5.5 kg ha‐1), and High (> 5.5 kg ha‐1).

• Pasture with different litter management • Mehlich 3 soil test P, High to Very High

• Phosphorus applications, 0‐80 kg ha‐1 yr‐1

.

Benchmark Water Quality TP Losses vs Model (APEX, APLE, and TBET) Predictions: Georgia


Benchmark Field Sites TP DP

DP/TP Ratio

APEX TP

APEX DP

APLE TP

APLE DP

TBET TP

TBET DP


GA (Pierson et al., 2001)

Field 2,1 5.77 4.09 0.71 0.28 0.20 9.39 9.32 6.78 6.41 High

Field 2,2 5.05 3.20 0.58 0.36 0.32 13.13 13.02 5.38 5.02 Mod

Field 4,1 9.32 7.20 0.77 0.87 0.32 4.51 4.49 4.14 3.92 High

Field 4,2 13.68 11.69 0.86 0.33 0.27 13.65 16.82 8.90 5.88 High

Field 6,1 10.83 7.53 0.70 0.77 0.55 9.98 9.93 8.60 8.11 High

Field 6,2 19.77 13.40 0.68 0.51 0.50 17.13 13.73 8.85 5.97 High

• Pasture with different rates of litter management• Mehlich 3 soil test P, Low to Very High

• Phosphorus applications, 215‐237 kg ha‐1 yr‐1

Benchmark Water Quality TP Losses vs Model (APEX, APLE, and TBET) Predictions: NC


• Cropland: Conventional tillage vs no‐till and conventional vs organic management• Mehlich 3 soil test P Medium to Very High

• Phosphorus applications on conventional management, 0 kg ha‐1 yr‐1• Phosphorus applications on organic management, 62‐114 kg ha‐1 yr‐1

Benchmark Field Sites TP DP

DP/TP Ratio

APEX TP

APEX DP

APLE TP

APLE DP

TBET TP

TBET DP


NC (Edgell et al., 2015)CT,C 2011 7.88 0.18 0.02 0.84 0.33 2.9 0.30 5.3 0.10 HighCT,C 2012 1.62 0.07 0.04 0.84 0.33 4.0 0.26 10.3 0.15 LowNT,C 2011 0.69 0.15 0.22 0.09 0.03 4.0 0.58 5.8 0.17 LowNT,C 2012 0.27 0.06 0.22 0.09 0.03 5.5 0.35 9.8 0.16 LowCT,O 2011 3.08 0.63 0.20 0.23 0.06 11.9 6.29 9.2 0.26 ModCT,O 2012 1.79 0.26 0.15 0.23 0.06 10.1 2.66 15.6 0.23 LowNT,O 2011 1.05 0.30 0.29 0.05 0.01 9.4 5.57 9.3 0.76 LowNT,O 2012 0.47 0.14 0.30 0.05 0.01 7.8 2.07 11.7 0.28 Low

Arkansas Benchmark Data:Southern State P‐Index Ratings

AR Field Sites

NRCS† AL AR FL GA KY LA MS NC OK SC TN TX

Southern State P Index Ratings Using Measured Sediment for Erosion LossesCheck Low Low Low Low Low Low Low Low Low High Low Low LowBroadlitter Low High Mod Mod Low Low Low Mod Low High Low Low ModInjectlitter Low High Low Mod Low Low Low Mod Low High Low Low ModInjectlitterx2 Low High Mod Mod Low Low Low Mod Low Severe Mod Low ModRotGraz+litter Low High Mod Mod Low Low Low Mod Low High Mod Low ModContGraz+litter Low High Mod Mod High Mod Low Mod Low Severe Mod Low Mod

Hay+litter Low High Mod Mod Low Low Low Mod Low High Mod Low Mod† NRCS ranking equivalencies Low (< 2.2 kg ha‐1), Moderate (2.2 to 5.5 kg ha‐1), and High (> 5.5 kg ha‐1).

Georgia Benchmark Data:Southern State P‐Index Ratings

† NRCS ranking equivalencies Low (< 2.2 kg ha‐1), Moderate (2.2 to 5.5 kg ha‐1), and High (> 5.5 kg ha‐1).‡Oklahoma P Index would not allow this much P

GA Field Sites


Southern State P Index Ratings Using Measured Sediment for Erosion Losses

Field 2,1 HighEx. High Low

V. High

V. High Low Mod High High NA‡

V. High Mod High

Field 2,2 ModEx. High Low

V. High

V. High Low Mod High Mod NA

V. High Mod High

Field 4,1 HighEx. High Low High

V. High Low Mod High Low NA

V. High Mod Mod

Field 4,2 HighEx. High Low

V. High

V. High Low High High Mod NA

V. High High High

Field 6,1 HighEx. High Low Mod

V. High Mod Mod High Mod NA

V. High Mod High

Field 6,2 HighEx. High Low Mod

V. High Mod High High High NA

V. High High High

North Carolina Benchmark Data:Southern State P‐Index Ratings


NC Field Sites


Southern State P Index Ratings Using Measured Sediment for Erosion Losses

CT,C 2011 High Low NA Low Low Low Low Low Low Low Low Low Low

CT,C 2012 Low Low NA Low Low Low Low Low Low Mod Low Low Low

NT,C 2011 Low Low NA Low Low Low Low Low Low Mod Low Low Mod

NT,C 2012 Low Low NA Low Low Low Low Low Low Mod Low Low Mod

CT,O 2011 Mod V. High NA Mod V. High Mod Low Mod Low Mod High Mod Mod

CT,O 2012 Low V. High NA Mod High Low Low Mod Low Mod Mod Mod Mod

NT,O 2011 Low V. High NA Mod V. High Low Low High High Mod High High Mod

NT,O 2012 Low V. High NA Mod Mod Low Low Mod Mod Mod High High Mod


Southern State P‐Index Ratings: Translation of State Management Outcomes

NRCS P Index RatingState N‐based (Low) P‐based (Moderate) No P (High)

State P‐Index Ratings AL Low Moderate, High Very HighAR Low, Moderate High Very HighFL Low Moderate High, Very HighGA Low, Moderate High Very HighKY Low Moderate HighLA Low, Moderate High Very HighMS Low, Moderate High Very HighNC Low, Moderate High Very HighOK Low, Moderate High Very High, SevereSC Low, Moderate High Very HighTN Low Moderate, High Very HighTX† Low Moderate, High, Very High High, Very High with P

impairment† Rankings vary based on water quality impairment

Southern State P‐Index Rating: Number and Percentage by Category

Benchmark Field Sites

State NRCS†P‐Index Rating

Number of Southern P‐Index Ratings by Category

% Southern P‐Index Ratings by Category

Low Mod High Low Mod HighCheck

AR

Low 11 1 0 92 8Broadlitter Low 8 4 0 67 33Injectlitter Low 8 4 0 67 33Injectlitterx2 Low 8 3 1 67 25 8RotGraz + litter Low 8 4 0 67 33ContGraz + litter Low 6 5 1 42 50 8Hay + litter Low 8 4 0 67 33Field 2,1

GA

High 4 4 4 33 33 34Field 2,2 Mod 5 3 4 42 25 34Field 4,1 High 5 3 4 42 25 34Field 4,2 High 4 4 4 33 33 34Field 6,1 High 4 4 4 33 33 34Field 6,2 High 2 6 4 17 50 33CT,C 2011

NC

High 11 0 0 100 0 0CT,C 2012 Low 11 0 0 100 0NT,C 2011 Low 10 1 0 91 9NT,C 2012 Low 10 1 0 91 9CT,O 2011 Mod 5 4 2 46 36 18CT,O 2012 Low 6 5 0 55 45NT,O 2011 Low 4 5 2 36 46 18NT,O 2012 Low 7 2 1 64 27 9

Percent correspondence with NRCS loss rating

34

6152

48

6064

P INDICESTBET APLEAPEXAdded Multi Comp

Phosphorus Loss Tools• Additive Indices: AL (39%),

TX (28%) • Multiplicative Indices: AR

(54%), FL (52%), LA (61%), MS (58%), SC (81%), TN (55%)

• Component Indices GA (71%), KY (61%), NC (61%)

• Qualitative Index: OK (39%)

• Overall Rating: 54%

Conclusion1. “Correctness” of P Indices can change based on how ranking

losses are established.2. Most southern states have kept 4 loss rating categories but

tied them to 3 management practice outcomes, which causes variations in rating interpretation across states and makes comparisons difficult.

3. Southern P Indices are just as robust as the more hard to use water quality models but all only predict loss correctly ~ 55%.

4. Most Southern states have little political will to implement or use P Indices so major changes may be unrealistic.

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Southern p indicies osmond

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