Legacy PhosphorusThe Perplexing Pollution Problem from

People’s Poultry Preference

Amy L. Shober Associate Professor and Extension Specialist

Nutrient Management and Environmental QualityUniversity of Delaware

University of Delaware Cooperative Extension

People Increasingly Prefer Poultry

University of Delaware Cooperative Extension 1

0

20

40

60

80

100

Per C

apita

Mea

t C

onsu

mpt

ion

(lbs)

BeefPorkChickenTurkey

National Chicken Council (2015)

Dela…Where?

2University of Delaware Cooperative Extension

Near lots of those people who prefer poultry!

• Annual broiler production exceeds 200 Million

• Proximity to fresh markets• Sussex county 1st in U.S.• Grain crops grown to

support poultry industry• 2012 grain production

– 182,000 acres corn for grain– 168,000 acres soybean

Poultry Rules the Roost in DE

3

Sussex County Broiler Production

Source: USDA-NASS, 2014

University of Delaware Cooperative Extension

Artificial Drainage Networks are Common on Delmarva

• Required for production of grain crops in some areas – Poorly drained soils– High water tables

• Mainly open ditch networksengineered to remove excess water

• Conduit for nutrients to sensitive waterbodies

University of Delaware Cooperative Extension 4

Source: DPI, 2012

Grain Imported (2010)Corn = 19 million buSoy = 8 million bu

≈2,728 Tons of Pimported!

Delmarva Grain Yields Unable to Meet Poultry Industry Needs

01020304050607080

Produced Consumed

Gra

in (M

illio

n bu

)

Corn Soybeans

5University of Delaware Cooperative Extension

Grain P

Manure P

Manure P

P Rock

Manure Produced on the Shore Stays on the Shore

6University of Delaware Cooperative Extension

Top SourcesMorocco

IraqChinaAlgeriaSyria

Historical Manure Management• Beneficial recycling of nutrients & organic matter• “Nitrogen-based” application rates• Environmental protection strategies

– Groundwater: nitrate leaching

– Surface waters: soil erosion

– Human health: metals, organics, pathogens….

P?University of Delaware Cooperative Extension 7

0 25 50 75 100 125 150

Manure-PCorn

SoybeansWheatAlfalfa

PotatoesSweet Corn

P Added in 10 Mg ha-1 of Poultry Manure* vs. Crop P Removal (kg ha-1)

Average annual P excessfor poultry manure use in a

corn-soybean rotation:~100 kg P ha-1 yr-1*

N-based Manure Applications Led to Over-application of P

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*Prior to industry adoption of phytase in feed

Phosphorus Behavior and TransportSoil erosion & particulate P

Subsurfaceflow

Tile flow

P leachingis small Total P – 5%

Crop P harvest15%

Soil P immobilization – 80%

Release ofsoil P dissolved P

9

Soil solutionH2PO4

-Soil solution

H2PO4-

Soil solutionH2PO4

- Al-P & Fe-PAl-P & Fe-PAl-P & Fe-PSATURATED

Build Up of Soil Test PFertilizer PManure P

10

LEGACY P

Delaware Soil Test P Distribution Agronomic Samples

University of Delaware Cooperative Extension 11

FY 2011-2015

0%

20%

40%

60%

80%

100%

New Castle Kent Sussex

Low (0-25) Med (26-50) Opt (51-100) Ex (>100)

Relationship Between Soil Test P and Soluble P in Delaware Soils

02468

101214161820

0 200 400 600 800 1000 1200 1400

Solu

ble

P (m

g/kg

)

Mehlich 3 Soil Test P (mg/kg)

SussexKentNew Castle

12

Opt

imum

STP

Ran

ge

Pautler and Sims, 2000

(n = 122)

University of Delaware Cooperative Extension

Soluble P is Susceptible to Runoff Losses (Overland Flow)…

0 10 20 30 40 500.00

0.25

0.50

0.75

r = 0.74**

DRP = 0.1 mg L-1

Water soluble P at 0-5 cm (mg kg-1)

Run

off D

RP

(mg

L-1)

Vadas et al. (2005)

University of Delaware Cooperative Extension 13

200

150

100

50

0300 mg kg-1

10 mg kg-1

5 mg kg-1

5 mg L-1

2 mg L-1

0.5 mg L-1

Mehlich-3 P P concentration Drainage ditch

90 %

10%

…and Losses through Artificial Drainage Networks

University of Delaware Cooperative Extension

Dep

th b

elow

land

sur

face

(cm

)

14

Slide credit: Ray Bryant (USDA-ARS)

• Delaware Nutrient Management Law 1999– DE Nutrient Management

Commission– Certification– Animal Waste and Nutrient

Management Plans• Poultry industry adopts

phytase feed additive

Pfiesteria Hysteria Leads to Mandatory Nutrient Management

15University of Delaware Cooperative Extension

Delaware Nutrient Management Commission

• Consists of 15 Voting members:– Administrator of Conservation Districts, DNREC– 7 full-time farmers– 1 commercial/agricultural nutrient applicator– 1 commercial nursery industry– 1 golf course/lawn care industry– 2 environmental group representatives– 1 nutrient consultant– 1 public citizen

16University of Delaware Cooperative Extension

• Program Administrator– Chris Brosch

• Environmental Scientists– Bob Coleman– Brooke Walls– Aaron Givens– Clint Gill

DE Department of Agriculture

302-698-4500, 800-282-8685

http://dda.delaware.gov/nutrients/index.shtml

Nutrient Management Program

University of Delaware Cooperative Extension 17

• Current Members– Amy Shober– Jennifer Volk– Sydney Riggi– Terra Eby– Shawn Tingle– Rebecca Rothweiler

• Former Members– Greg Binford– Dave Hansen

UD Nutrient Management Extension Team

18University of Delaware Cooperative Extension

8 Animal Units 10+ Acres Fertilized

Who Is Affected By the Law?

19University of Delaware Cooperative Extension

Golf Courses

Turf & Athletic Fields

Lawn Care Companies

Agriculture

3200 Broilers

8 Beef Cattle

32 Brood Sows

7 Saddle Horses

40 Sheep

Categories for Certification

• Nutrient Generator: Generates nutrients (i.e. litter) but no land-application

• Private Nutrient Handler: Apply nutrients only to privately managed land

• Commercial Nutrient Handler: Apply nutrients as part of a commercial business

• Nutrient Consultant: Writes nutrient management plans

20University of Delaware Cooperative Extension

Certification RequirementsCertification Level

Session I & II

Session III

SessionIV Exam Continuing

EducationNutrient Generator X 6 CEUs every 3 years

PrivateNutrient Handler

X X 6 CEUs every 3 years

Commercial Nutrient Handler

X X X X 6 CEUs every 3 years

Nutrient Consultant X X X X 5 CEUs every year

21University of Delaware Cooperative Extension

What Topics Do We Cover?

Water Quality Manure Storage & Management

Mortality Management

State/Federal Law Basic Soils Fertilizers & Fertility Calculations

22University of Delaware Cooperative Extension

* Indicates the number that completed training and passed the exam.

Certification Program Statistics

23University of Delaware Cooperative Extension

Certification Level

Number of Certifications2001-2003 2004-2013 2013-2016 Total

Nutrient Generator 486 255 136 870

Private Nutrient Handler 1106 424 140 1624

Commercial Nutrient Handler N/A 102 46 145

Nutrient Consultant N/A 93 35 126

All Levels 1592 874 357 2765

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Impact of Certification

Other Details of the DE Law• Animal Waste and Nutrient Management plan

requirements• Annual Reports• Manure and Fertilizer applications are:

– Limited on “High” phosphorus soils– Prohibited between Dec. 7 and Feb. 15 (exceptions on

a case-by-case basis for dairies with storage issues)• Regulation of Concentrated Animal Feeding

Operations (CAFOs)

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High Phosphorus Soils• High P soils currently defined as any soil with a

soil test value greater than 150 FIV.– Phosphorus applications are limited to a

THREE-YEAR crop removal rate on soils that are considered high in P, unless…

– Phosphorus Site Index indicates another application method is appropriate.

• The DNMC has recommended the PSI as a BMP (Best Management Practice).

University of Delaware Cooperative Extension 26

Soil Test P Threshold Approach

Steep

Steep

Moderate

Soil Test Phosphorus (lb/acre)

Cro

p R

espo

nse

orEn

viro

nmen

tal I

mpa

ctAgronomicCritical SoilTest P Value

Environmental Impact

(e.g., P loss in runoff)

CropResponse

“Threshold P Value”

27University of Delaware Cooperative Extension

44

4620

92

Risk Assessment Tools ID Critical Source

Areas177

144

DP78

97

55

0

Tony Buda, USDA-ARS

Soil P – ppmP added – kg P/ha/yrRunoff – litersP loss – kg P/ha/yr

28

1

<1

DP

8

Critical Source Area• Overlap of source & transport indicators• Identify and manage the critical source areas• Phosphorus Index

- ID critical source areas

- Target management changes to high risk areas

- Maximize return on effort

Source Transport

Critical Source Area

Mahantango Creek Watershed, USDA-ARS

90% of P Loss comes from 10% of the watershed

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The P Index Version 1.0• Developed in 1992 (Lemunyon and Gilbert, 1993)• The initial goals of the P Index were to:

1. Assess the risk of P transport from a field to water body,

2. Identify critical parameters that influence P loss, and

3. Help identify management practices that would decrease P loss from a site.

30University of Delaware Cooperative Extension

The P Index Version 1.0CHARACTERISTIC(Weighting Factor)

PHOSPHORUS LOSS RATING (Value)NONE (0) LOW (1) MED (2) HIGH (4) V. HIGH (8)

Soil Erosion (1.5) N/A <5 5-10 10-15 >15Soil Runoff Class (0.5) N/A Low Medium High Very High

Soil Test P (1.0) N/A Low Medium Optimum ExcessiveP Fertilizer Rate (0.75) None <31 31-90 91-150 >150

P Fertilizer Method (0.5)

None Placed w/ planter >

2 in.

Incorp. <3 mo. before

crop

Inc. >3 mo. before crop;

surface <3 mo.before crop

Surfaceto pasture; >3 monthsbefore crop

Organic P Rate (1.0) None <31 31-90 91-150 >150

Organic P Method (1.0)

None Injected >2 in

Incorp. <3 mo. before

crop

Incorp. >3 mo.before crop;

surface <3 mo.before crop

Surfaceto pasture;

>3 mo.before crop

31University of Delaware Cooperative Extension

• Integral part of agricultural P management

• Written into USDA 590 standard and EPA CAFO rule

• State specific versions

Additive

Multiplicative

ComponentParticulate

Surface

Subsurface

Evolution of the P Index

Source Transport

Source Transport

+

×Source Transport

×

×Source Transport

×Source Transport+

University of Delaware Cooperative Extension 32

Part A – Transport

• Soil Erosion (RUSLE)• Surface Runoff Class• Subsurface Drainage• Leaching Potential• Distance from Water• Priority of Water

Part B – Source

• Soil Test P Level• P Fertilizer Rate• P Fertilizer Application

Method • Organic P Rate• Organic P Application

Method

The DE/MD P Site Index

PSI Rating = (Transport [A]) × (Source [B])

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Delaware PSI Risk CategoriesPSI Rating

Risk Category

Generalized Interpretation

< 50 Low N-based nutrient management acceptable. Soil P may increase.

51-75 Medium N-based nutrient management no more than 1 year out of 3. P-based nutrient management 2 years out of 3; P applications limited to crop removal or soil test P based application recommendations, whichever is greater.

76-100 High P applications limited to crop removal or soil test P based application recommendations. All practical management practices for reducing P should be implemented.

> 100 Very High No P application*. Active remediation techniques should be implemented to reduce P loss potential.

34University of Delaware Cooperative Extension

NRCS Funded P Index Evaluation

35

Chesapeake Bay

Heartland

Southern States

Single State

University of Delaware Cooperative Extension

• Establish 9 benchmarkwatersheds for testing/ evaluation of current P index using actual and modeled data

• Expert panels ID important site conditionsand management practices

• Refine and evaluate new P Indices

Chesapeake Bay CIG Project

University of Delaware Cooperative Extension 36

2011-2015

MD Develops the Phosphorus Management Tool (PMT)

Transport Source

Management

+ +P loss risk of dissolved P by subsurface movement

P loss risk of particulate Pby erosion

P loss risk of dissolved P by surface runoff

Transport Source

Management

Transport Source

Management

University of Delaware Cooperative Extension 37

Nicole Fiorellino, UMD

Maryland PMT Risk CategoriesPSI Rating

Risk Category

Generalized Interpretation

< 50 Low Total P application should be limited to no more than a three-year crop removal rate applied over three years.

51-100 Medium P applications should be limited to the amount expected to be removed from the field by crop harvest or soil-test P based application recommendations.

> 100 High No P application*. Active remediation techniques should be implemented to reduce P loss potential.

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Maryland P Management Tool Regulations Effective 2015

• P Management Tool (UM-PMT) phased in for new/updated nutrient management plans through 2018

• P application banned to soils with >500 FIV Mehlich 3 P

• Required reporting of soil test data to MDA every 5 years

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Subsurface Drainage Remains Poorly Understood

• Issues initializing WQ models (SWAT) in Coastal Plain limit P Index evaluation

• EPA pressures other Bay states to adopt UM-PMT approach

• Unable to fully evaluate MD-PMT subsurface transport using WQ data

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• Limited P load data available for evaluation

• MD-PMT approach appears to be better than DE-PSI approach

• Need more monitoring data

Subsurface Risk

41University of Delaware Cooperative Extension

y = 0.15x - 0.46r² = 0.33

00.5

11.5

22.5

3

0.0 5.0 10.0 15.0

y = 2E-09x4.017

r² = 0.72

00.5

11.5

22.5

3

0.0 100.0 200.0

Est.

Dis

solv

ed P

Loa

d in

Ditc

h D

rain

age

(kg/

ha) DE-PSI

MD-PMT

• Inconsistency in scoring across state lines

• Work needed to normalize scores and management

• Soil datasets may provide options for improvement

Discrepancies in Scoring

42University of Delaware Cooperative Extension

MD-PMT MD-PMT2 DE-PSI NC-PLAT VA-PI

P In

dex

Scor

e

0

50

100

150

200

250

300

N-based P-based 1.5x crop removal P-based 2 of 3 years P-based 3 yr crop removal P-based 1 yr crop removal No P application

UMES Subsurface P Transport Research

• Characterize subsurface flow paths and P movement at two ditched field sites on the Delmarva Peninsula (Atlantic Coastal Plain) using conservative tracers (Cl- and Br-) and ERI

University of Delaware Cooperative Extension 43

3D Images of Oct 2015 Event

Department of Plant and Soil Sciences 44

1-Oct 2015@1:10 PM

0

2

4

2

40 2 4 6 82480.2

0.8 1-Oct 2015@3:10 PM

0

2

4

2

4 0 2 4 6 82480.20.8

Changes in conductivity are shown as Log10(σi/σbkg) where i=ith dataset. These images have been scaled to show maximum changes.

3-Oct 2015@8:39 PM

0

2

4

2

4 0 2 4 6 82480.20.8

Scale in meters0.70.5750.450.3250.2

3D View--Tracer Infiltration

45

1-Oct 2015@1:10 PM

03.5

7

0.250.5

0.751.0

1-Oct 2015@3:10 PM

03.5

7

0.250.5

0.751.0

3-Oct 2015@8:39 PM

03.5

7

0.250.5

0.751.0

1.25

--0.7--0.575--0.45--0.325--0.2

Department of Plant and Soil Sciences

Scale in meters

• Understand how soil and hydrology can influence water flow and subsurface nutrient transfers

• Method to assess risk of subsurface P transport for use in next-generation P risk assessment tools

Potential Implications of This Research

46University of Delaware Cooperative Extension

• P Indices help guide management, but do not eliminate the underlying problems:– Regional P imbalance– Legacy P losses from

high P soils• NO current BMPs

address legacy P

P Index is NOT the Solution to the Perplexing Pollution Problem!

47University of Delaware Cooperative Extension

Phosphorus Drawdown Takes a Long Time (Forage > Grain)

University of Delaware Cooperative Extension 48

0

100

200

300

400

500

600

1990 1995 2000 2005 2010 2015 2020

0 kg/ha400 kg/ha800 kg/ha1200 kg/ha1600 kg/ha

Manure applications

Meh

lich

3 P

(mg/

kg)

Fiorellino et al. (2017)

28 years

19 years

Innovative BMPs: Filtration Structures for Treatment of Phosphorus

49University of Delaware Cooperative Extension

UMES Experiment StationEffective for 7-8 months: 25% overall dissolved P removal

Structure has handled flow rates over 100 gpm

University of Delaware Cooperative Extension

Innovative BMPs: Managing Ditch “Dip-Out” Spoils

• Spoils dredged to restore drainage are placedon adjacent field, spread, and incorporated

• Farmers do not like• Mixing spoil and soil near

ditch can reduce soluble P losses and impact less land

50

Department of Plant and Soil Sciences

Innovative BMPs: Si and Other Amendments to Solubilize Soil PAgrowSil (CaSiO4) Switchgrass Ash Silicic Acid

• Applied at 0, 0.25, 0.5, 1, and 2 Mg Si ha-1 (3 replicates)

• Legacy P is not your grandfather’s problem anymore!

• We’ve improved manure management

• Continued improvement of risk assessment tools

• Still lots to learn!

After Decades of P Research in Delaware and the Mid-Atlantic..

52University of Delaware Cooperative Extension

1

2

43

5

6

7

1. Cornell University2. Penn State Univ./ USDA-ARS3. Univ. of Maryland – College Park4. Univ. of Maryland – Eastern Shore5. Univ. of Delaware6. Virginia Tech7. West Virginia University

Along with…Federal and state agencies; Industry groups; Commodity groups, etc.

Nutrient Management Research through Regional Collaboration

53University of Delaware Cooperative Extension

Cooperators:– Tom Sims– Nicole

Fiorellino– Josh McGrath– Chad Penn– Jennifer Volk– Shawn Tingle– Ray Bryant– Tony Buda– Lee Slater– Art Allen

– Doug Beegle

– Doug Beegle– Quirine

Ketterings– Tom Basden– Frank Coale– Pete Kleinman

Graduate Students:– Kathryn Clark– Zhixuan Qin– Melissa Savin

Funding provided by:– USDA-NRCS– DE Department of Natural

Resources and Environmental Control

– Delmarva Land Grant University Seed Grant

Work Completed at:– National Synchrotron

Light Source– Advanced Photon Source

Acknowledgements

54University of Delaware Cooperative Extension