future phosphorus labeling...

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Future Phosphorus

Labeling Considerations

Presented by:

Ron Alexander, R. Alexander Associates, Inc.

US Composting Council 2/12/19

Functions of Phosphorus

in Plants

Phosphorus is involved in many plant processes, including:

• Energy transfer reactions • Development of • reproductive structures • Crop maturity • Root growth • Protein synthesis

Phosphorus Cycle

• Phosphorus is primarily adsorbed by plants in the ionic forms H2PO4– and HPO4

=

• These orthophosphates originate largely from primary and secondary

minerals and/or from organic sources

• There are many factors that affect the availability of phosphorus in the soil

Phosphorus Reaction in Soil

• Phosphorus is found in soils both in an organic and mineral form; its solubility in soil is low

• Plants can only take up phosphorus dissolved in the soil solution, but since most soil phosphorus exists in stable chemical compounds, only a small amount is available to plants at any given time

• Active uptake is an energy consuming process, so conditions that inhibit root activity, such as low temperatures, excess of water etc., inhibit phosphorus uptake as well

Soil Phosphorus – P can be bound for years in finely textured soils;

especially in finer and calcareous soils

– In low pH conditions, P binds with Al (Fe and Mn)

– In higher pH conditions, P binds with calcium

P is a primary nutrient

needed to grow food / plants

Should avoid wasting or

over applying it

There are various State initiatives

to reduce P application and

remove it from fertilizers (and

sometimes soil amendments)

Picture courtesy of Dr. H.A. Elliott, PSU

States Installing P

Regulations • Minnesota and Florida were the first to address

P fertilizer usage and practices because of

environmental concern

• Typically states don’t ban P usage, just

severely reduce its usage

– 16 States – CT, DE, FL, IL, ME, MD, MA,

MI, MN, NH, NJ, NY, VT, VA, WA, WI

• Urban turf is the primary focus

(especially turf maintenance),

as well as agriculture through

nutrient planning

States Installing P

Regulations

• Problematic for soil amendments with innate

nutrient content, and/or making nutrient claims

• In some of these states, carbon-base soil

amendments are exempt; especially if no

nutrient claims are made

- Arguably, P regulations are often (politically

motivated) and don’t manage the ‘real’ or most

significant problems

- Sometimes they don’t rely on the ‘best available

science’

Phosphorus Reduction

Regulations State Actual P Ban? Compost Included?

CT Effective Jan. 2013 Exempt, unless reg. as a fertilizer

FL Yes, all products for lawn & turf Only exempt if un-manipulated with no claims

IL Yes, to commercial applicators only

Yes, IF applicator is using a compost claiming

nutrients

ME No actual ban, just must prove soil need for P Exempt, unless reg. as a commercial fertilizer

MD No actual ban, just must prove soil need for P Exempt, unless reg. as a fertilizer

MI Full effect in Jan. 2012 Compost not regulated unless reg. as a fertilizer

MN No actual ban, just must prove soil need for P Yes, if labeled as fertilizer, No if not reg. as fertilizer

NJ

Fertilizer consists of manipulated animal or vegetable manure

(organic sources). In this case, phosphorus can be included if no

more than 0.25 pound of phosphorus per 1,000 sq. ft. is applied,

when used according to instructions on the container

Not specific beyond the language about organic

sources

NY No actual ban, just must prove soil need for P Exempt, unless reg. as a commercial fertilizer

VT No actual ban, just must prove soil need for P Exempt

WA No actual ban, just must prove soil need for P Exempt, unless reg. as a commercial fertilizer

WI Turf & lawn fert. containing Phosphate Unadulterated animal & vegetable 'manures' exempt

- -Tracked to consider affect on compost usage

- -AAPFCO has been involved in creating model language for urban turf

Real

Problem

That stated,

P (and N) migration into water is a

‘real’ problem

50,000 impacted waterways in US

How Did We Get Here?

Causes…

• Many agricultural sites with a history of

manure application already have soil test P

beyond levels needed to maximize crop yields

• Applying manure and biosolids (and other

materials) to satisfy crop nitrogen need has

resulted in excess P applied

How Did We Get Here?

Causes…

• P is readily tied up in fine textured soils, so

we tend to over apply it to get plants the

amount they need

– Luxury applications of P in soil typically don’t hurt

crops

• Inorganic fertilizer based P has been over

applied in agricultural production and turf

management for many years

Lake Okeechobee and Chesapeake Bay are well known examples,

over fertilization and runoff in agricultural is the primary cause

Soil Phosphorus

Solution

Labile

Stable (Less labile)

From Craig Cogger, WSU

Treat more stable P source

materials differently ?

Environmentally

significant

Plant-Available

Complicated Issue • Phosphorus movement and availability is soil

(texture, chemistry [Fe, Al, Ca]) and P form

dependent

• Research is gathering data for P indexing and

creating P source co-efficient (rating P on WEP) as

a tool for agricultural usage of P

• ‘P Problem’ is 3 separate issues (More?)

-Confined Animal Feeding Operations (CAFO’s)

- Over application of manure

-Soil erosion*

-Fertilizer P application

PROBLEM …

Most state P regulations and

indices treat organic and inorganic

fertilizers, manures, compost,

biosolids, the same, in terms of

their P solubility and runoff /

leaching potential

This is Incorrect…

Regulation has to move towards using

Modified from Dr. H.A. Elliott

P Indexing Concept and

Components

Transport Factors

• Soil erosion

• Leaching potential

• Runoff potential

• Distance to water

body

Source Factors

• Soil test P

• P2O5 application rate

• Application method

• Application timing

and management

Slide courtesy of Dr. H.A. Elliott

-P Index – ag based risk assessment tool, quantify potential for P runoff

in specific fields (P usage dependent on field orientation/conditions)

-Determines base allowable amount of P on land based on above factors

P Source Co-Efficient Rating Suitability for Regulation

P Source Poor

(one-size-fits-all)

Better (categories)

Best* (continuous

parameter)

Mineral

Fertilizer

1.0

1.0 1.0 Biosolids,

Manures,

Composts,

Food

Processing

Residuals,

etc..

0.8 Source- specific values*

0.4

0.3

0.2 0

Ru

no

ff &

Le

ach

ing

Po

ten

tia

l

*P Source Co-efficient = 0.102 × WEP 0.99

Where: WEP = water extractable P test value for P

source

Slide courtesy of Dr. H.A. Elliott

-Using accurate data for individual products is key to

good regulation and environmental protection

-Started as agricultural tool, but has broad application in

fertilizer usage / planning / regulation

Conclusive Research Exists

Research data acknowledges that : Dr. Herschel Eliott

-Different products have different WEP %’s

-Total P in a product is NOT a good indicator of environmental risk,

especially with carbon-based products

University Research

Water Extractable vs. Total P

Phosphorus Source Water Extractable

Phosphate (% of Total P)

Heat dried biosolids

(such as Milorganite® 6-2-0)

<2 %

Biological Phosphate Removal –

type biosolids

5 – 25 %

Poultry manure 20 %

Dairy manure 50 %

Triple Super Phosphate (0-44-0

synthetic)

85 %

Dr. George O’Connor, University of Florida)

(Presented at AAPFCO in 2013)

Carbon-Based Fertilizer Products

& Water Extractable P

2-6-3 product was

approximately 23% WEP 6-2-0 product was

approximately 2% WEP

Feedstocks

Biosolids

Treatment Tot. Sol.

% pH

P2O5

% dw P % dw

P ppm

dw

WEP ppm

dw

WEP

% of Tot. P

Leaf/yard wastes NA 39.4 7.7 0.34 0.15 1,485 124.6 8.4%

Leaf/yard wastes/food NA 47.5 7.4 0.42 0.18 1,817 134.0 7.4%

Leaf/yard wastes/food NA 53.9 7.4 0.43 0.19 1,873 126.9 6.8%

Biosolids/wood chips No P removal 39.8 7.2 0.78 0.34 3,424 703.0 20.5%

Biosolids/wood chips / Yard

wastes No P removal 72.1 6.6 0.81 0.35 3,537 430.5 12.2%

Biosolids/wood chips No P removal 48.1 6.7 1.60 0.70 6,991 1,559 22.3%

Biosolids/Yard wastes / WTR No P removal 53.5 8.3 1.67 0.73 7,293 336.5 4.6%

Biosolids/Yard wastes / WTR No P removal 47.8 7.9 1.68 0.73 7,345 298.1 4.1%

Biosolids/wood chips

An. digest /No P

removal 59.2 7.2 1.87 0.82 8,183 633.7 7.7%

Leaf/yard wastes / Gelatin

residuals N/A 51.1 8.3 2.19 0.96 9,581 195.4 2.0%

Biosolids/wood shavings

Biological P

removal 42.8 5.7 2.41 1.05 10,524 1,398 13.3%

Biosolids/wood chips

Chemical P

removal 38.8 5.5 3.65 1.59 15,939 287.3 1.8%

Data courtesy of Dr. Geoff Kuter, Agresource

Testing through Penn State University, Dr. John Spargo

Compost

Total P2O5 vs. Water Extractable P

RESULTS / INTERPRETATION

• Amount of P (and forms) in compost varies significantly

• Amount of P that is WEP is low in comparison to the total P.

The WEP ranges from about 2% to 22% of the total P

• Amount of WEP is only loosely correlated with total P.

L/YW compost generally has lower WEP than biosolids

compost, but biosolids with high Fe, Al, Ca has low WEP

• Percentage of P that is WEP is very closely correlated with the

amount of Fe and Al in the individual product

• Total P in products IS NOT a viable predictor of mobility /

availability

• Other research - WEP highest in inorganic fertilizer,

manure typically higher than compost and biosolids

Compost

Total P2O5 vs. Water Extractable P

Organic Matter & P Availability

“There was no evidence that P solubility was enhanced in soils with higher levels of organic matter; in fact, soils with higher levels of organic matter tended to have less P in solution at all levels of soil test P than soils with lower levels of organic matter.

Higher SOM levels were associated with higher levels of oxalate-extractable Fe and Al and, therefore, higher P sorption capacities….”

- Ohno et al., Univ. of Maine, 2006

Slide courtesy of Ned Beecher, NEBRA

Definitions

– Phosphorus is expressed as Available Phosphate

– P-2 - Available phosphate (P2O5) – is the sum of the

water soluble and the citrate soluble phosphate (1993)

– T-76 – No Phosphate Fertilizer - products with

phosphate levels below 0.5% intended for established

urban or lawns (2009)

– T-77 - Low Phosphate Fertilizer – products intended for

established urban or lawns, with available phosphate

levels equal or above 0.5% P2O5 and an application rate

not to exceed 0.25 lb P2O5 / 1,000 sf / application and

0.5 lb P2O5 per 1,000 sf per year (2016)

– Plant available phosphate – not defined

AAPFCO Efforts

AAPFCO Efforts • Uniform State Fertilizer Bill p.40, section 4, (c)

(2) – allows certain P sources the ability to

claim Total Phosphate

• SUIP 34 – Fertilizer Restrictions for Urban

Landscapes - Lays out suggested format for states

implementing fertilizer restrictions (N/P relevance)

- Provides for recycled products - (d) whether to

support recycling programs for biosolids, compost,

natural organic fertilizers or manure-based products

by excluding them or allowing a low phosphorus

application rate to comply with the restrictions.

Consider doing more, to give states more options to regulate,

and gather additional data on risk and options to address

Current Labeling Status

OP (1993) allows N claims based on form (mobility)

GUARANTEED ANALYSIS

Total Nitrogen (N)* 10%

2.5% Ammoniacal Nitrogen

2.5% Nitrate Nitrogen

5.0% Urea Nitrogen

Available Phosphate (P2O5) 15%

Soluble Potash (K2O) 20%

Sulfur (S) 14%

*___% Slowly available nitrogen from _______

(list source material).

Current Labeling Status

2019 AAPFCO Product Labeling Guide illustrates slowly

releasing P claim (example for all P in slow release form?)

Guarantee for Two Slowly

Available Materials

GUARANTEED ANALYSIS

Total Nitrogen (N) x%

x% Ammoniacal Nitrogen

x% Nitrate Nitrogen

x% Urea Nitrogen*

Available Phosphate (P2O5)** x%

*x% Slowly available urea nitrogen from _______

(list source material).

**x% Slowly available phosphate from ______.

NUTRIENT USE WORKING GROUP PHOSPHORUS / PHOSPATE EMPHASIS

Issues / Goals

• Phosphorus/Phosphate is being more aggressively

regulated by States because of environmental reasons /

concerns

• Existing regulations typically do not distinguish the

mobility of the P when regulating its usage (some do for N)

• Helpful to provide end users / buyers with additional

information on the leachability / availability of the P

fertilizer they are purchasing

• Helpful to provide states with other options to improve /

manage P usage, as related to environmental risk


TEST METHODS

• Citrate extractable P method for P2O5 (current method)

• Current P test method (Available Phosphate) best for

mineral (inorganic) forms of P, not a good indicator of

available P from carbon-based product (various

university research has proven this)*

• Standard WEP test methods do exist*

• Several universities studying WEP as an indicator of P

movement and loss (environmental risk), as well as

plant availability

*Can provide data to Lab Services Committee for review


Requests

• Allow additional information on product labels

regarding release / availability / mobility of P

– Inside or outside of guaranteed analysis (HOW?)

• Create Necessary Definitions

– Slowly available phosphate (?)

– Water extractable phosphate (?)

• Use as indicator of P leachability (and availability)

• Put Labeling Guide allowance / example (B.5.) in

the Official Publication (modify first?)

Not suggesting moving away from citrate extractable P test method

for carbon-based products, just allow additional information on label

Labeling Considerations

•Allow labeling language that delineates release

rate / mobility of P (OPTIONS?)

Total Nitrogen (N) ………………...6.0%

5.0% Water Insoluble Nitrogen*

1.0% Water Soluble Nitrogen*

Available Phosphate (P2O5)…….2.0%

0.5% Water Soluble Phosphate**

Soluble Potash (K2O)……………..3.0%

Derived from Composted Buffalo Manure and

Sea Kelp.

*1.0% Slowly available nitrogen from

Composted Buffalo Manure

**0.5% Water soluble (extractable) phosphate

from Composted Buffalo Manure

Total Nitrogen (N) ……………….…..6.0%

5.0% Water Insoluble Nitrogen*

1.0% Water Soluble Nitrogen*

Available Phosphate (P2O5)…….….2.0**%

Soluble Potash (K2O)………………..3.0%

Derived from Composted Buffalo Manure and

Sea Kelp.

*1.0% Slowly available nitrogen from Composted

Buffalo Manure

**2.0% Slowly available phosphate from

Composted Buffalo Manure

OR

**This product contains phosphorus with a low

level of extractability (10% of Total Available

Phosphate)

If Approved, Next Steps

• Determine how to provide the additional

P data on the label

• Evaluate WEP test method, as

necessary

• Create new related definitions ? – Water extractable phosphorus

– Slow release phosphorus

– Ortho phosphorus

• Re-purpose existing definitions ? – Slow release fertilizer

Final Thoughts

• Promote science-based regulation

• Promote means to better generate

field data regarding P movement

• Provide the buyer more information

• Provide state regulations another

option to address P drift

QUESTIONS ?

Ron Alexander

R. Alexander Associates, Inc.

Apex, NC – www.alexassoc.net

[email protected]

919-367-8350 o, 919-349-0460 m

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