fractionation of soil phosphorus by hedley’s procedure:...

Núcleo Regional Sul

Fractionation of Soil Phosphorusby Hedley’s Procedure:Uses and Limitations

Luciano Colpo GatiboniSanta Catarina State University

[email protected]

Seminário"Disponibilidade e manejo de fósforo no solo”

26/11/2012, Piracicaba-SP

Núcleo Regional SulNúcleo Regional Sul

I – Soil phosphorus forms

II – Some procedures for P fractionation

III – Limitations

IV - Examples of use

Presentation Parts




III - Limitations

IV – Examples of use

Presentation Parts


PHOSPHORUS FACTS:

80% of soils in Latin America are P-limiting

(Sanches & Salinas, 1981)

Highly weathered soils havehigh P-sorption

What mechanisms are involved?


Ca5(PO4)3X

Cl-

OH-F-

CO3-2

APATITES

PRIMARY P MINERALS

P

Ca

O

X


Tetrahedric shapeMolecular geometry

PHOSPHORUS FACTS:


“attachment”

2:1

Clay


Monodentate bond

- Commom for all types of clay

- Reversible

CHEMISORPTION Parfitt (1978)

INORGANIC PHOSPHORUS


Bidentate bond

- Occurs in Silicated clays and oxides (Fe, Al)

- Low reversibility


Binuclear Bond- Occurs in Oxides (Fe, Al)

- IRREVERSIBLE ???


ELETROSTATIC ADSORPTION

Cation

Anion

-

-

-

-

-

-

distance

Cla

y s

urf

ace

Electrostaticattraction

DiffusionElectrostatic

repulsion

P

P

P

P

PP

P

INORGANIC PHOSPHORUS

P diffusion


Chemisorption

(colloid surface)Monodentate

BidentateBinucleate

Physic adsorption

Diffuse double layer

Soil solution P

P max

Precipitation

Soil solution

ad

sorb

ed

P


How can we extract from soil

these different kinds of

inorganic P?


ORGANIC PHOSPHORUS

Monoester-Po

Inositol-6P

Glucose-P

Polyphosphates

ATPPhosphonates

Phosphonic acid

Diester-Po

P-choline

phospholipids

PPBMSBMS

Microbial Po

DE

CO

MP

OS

ITIO

N

DE

CO

MP

OS

ITIO

N

DE

CO

MP

OS

ITIO

N

80%




organic P?

P

PMINERALS

PoPiPi

PPBMSBMS


SOIL P DYNAMICS


Labile Pi

Available Pi

Fast Pi

Exchangeable Pi

Non-labile Pi

Recalcitrant Pi

High-energy Pi

Slow Pi

Ocluded Pi

Moderately-labile Pi

??PiPi

Binuclear Bidentate Monodentate Physic adsorption ?


?

?PoPo

Labile Po

Available Po

Fast Po

Exchangeable Po

Non-labile Po

Recalcitrant Po

High-energy Po

Slow Po

Ocluded Po

Moderately-labile Po

Monoester Diester Phosphonates Poliphosphates ?Microbial-P




inorganic and organic P?

Maybe using extractants

with differents mode of actions

or with difference in power of

extraction ?!




III - Limitations


Presentation Parts


Soil P fractionation

Different extractants used SEQUENCIALLY

- different mode of actions

- increasing power of extraction

Method validationMethod validationP solubilization from synthetic compoundsCo-solubilization of another ionsX-rays analysisSpectroscopic analysis

Soil

Extactant AP-form A

Extactant BP-form B

Extactant CP-form C


Soil P fractionation

FIRST FRACTIONATION:

FRAPS, G.S. Availability of phosphoric acid of the soil. J. Amer. Soc. Agron. 28:823-834, 1906. (apud Chang & Jackson, 1957)

FIRST FRACTIONATION WIDELY USED :

CHANG, S. C.; JACKSON, M. L. Fractionation of soil phosphorus. Soil Sci. 84:133-144, 1957.


Types of P fractionation

a) Pi Frac.

a) Po Frac.

a) Pi + Po Frac.

a) Pi + Po + Pm Frac.

Ivanoff et al. (1998)

Tiessen & Moir (2008)

Chen et al. (2000)

Condron & Goh (1989)

Chang & Jackson (1957)

Bowman & Cole (1978)

Hedley et al. (1982)


1 g soil +50 mL NH4Cl

1 mol L-130min. de agitationcentrifugation extract

Pi-water

50 mL NH4F

0,5 mol L-1

60min. de agitationcentrifugation extract

Pi-Aluminiun

50 mL NaOH

0,1 mol L-1

17h agitationcentrifugation extract Pi-Iron

60min. agitationcentrifugation extract

Pi-Calcium

50 mL H2SO4

0,25 mol L-1

60min. or 17 h agitationcentrifugation extract

Pi-Ocluded

50 mL NH4F

0,5 mol L-1

or50 mL NaOH

0,1 mol L-1

Chang & jackson(1957)

Advantages:

- Widely used

- Many papers correlatingwith plants

- Many papers correlatingwith extractants

Limitations:

- Po is not determined

-P forms aren’t linkedwith availability


Bowman & Cole (1978) and Ivanoff et al. (1998)

1 g soil +2 mL CHCl3 +50 mL NaHCO3

0,5 mol L-1

1 g soil +50 mL NaHCO3

0,5 mol L-1

Discard

the soil

16 horas de agitationcentrifugation extract

Ptf-Pt = microbial P

50 mL NaOH

0,5 mol L-1 16h agitationcentrifugation Extract digestion

Pt-NaOH

Acidification until pH 0,2

centrifugation

Pt-Pi =Po-AF

Precipitate

(Humic ac.)

Dry Digestion (550ºC, 1h)

Extract (fulvic ac.)Pi-NaOH

digestion Pt-AF

Pt-NaOH – Pt-AF = Po-AH

Set A Set B

16h agitationcentrifugation extract Pi-NaHCO3

digestion

Pt-Pi =Po-NaHCO3

Pt-NaHCO3

50 mL HCl

1 mol L-1 3 horas de agitationcentrifugation extract Pi-HCl

Residual P

soil

Ptf-NaHCO3

fumigated

Alkaline soultionsExtract Pi and

SOM (Po)

Microbial PFumigation with CHCl3


Bowman & Cole (1978) and Ivanoff et al. (1998)

Advantages:

- Po forms related to lability: - Labile-Po- Fulvic Ac.-Po- Humic Ac-Po

- Po forms related to SOM fractionation

- Quantification of Microbial P

Limitations:

- Pi is not determined

- Humine-Po is notdetermined

(only by difference if PoT is determinated)


30 mL NaOH

0,1 mol L-1 16h agitationcentrifugation

extractPi-NaOH I

digestionPt-Pi =Po-NaOH IPt-NaOH I

Set B

16h agitationcentrifugation

extract Pi-resin

Discard

the soil

16h agitationcentrifugation extract Pi-NaHCO3

digestion

Pt-Pi =Po-NaHCO3

Pt-NaHCO3

0,5 g soil +30 mL H2O +RESIN

Set A


Discard

extract

1 mL CHCl3


extract

digestion Ptf-NaHCO3 Ptf-Pt =Microbial P

30 mL NaOH

0,1 mol L-1 +Sonification(75 w, 2 min.)


extractPi-NaOH II

digestionPt-Pi =Po-NaOH IIPt-NaOH II

30 mL HCl

1 mol L-1 16h agitationcentrifugation

extract Pi-HCl

Soil digestion

(H2SO4 + H2O2)

P residual

30 mL NaHCO3

0,5 mol L-1




Advantages:

- Extaction of inorganic and organic P forms

- Extraction of Microbial P during the process

- The first extractant is resin (available-P to plants)

- P forms extracted since labile until non-labile forms

- Widely used in the last 30 years

Limitations:

- High complexity- Time consuming


Hedley et al. (1982)modificated by

Condron & Goh (1989)

30 mL NaOH

0,1 mol L-1


extractPi-NaOH I


extract Pi-resin

extract Pi-NaHCO3

digestionPt-Pi =Po-NaHCO3

Pt-NaHCO3

0,5 g soil +30 mL H2O +resin



30 mL NaOH


extractPi-NaOH II


30 mL HCl

1 mol L-116h agitationcentrifugation

extractPi-HCl

Soil digestion (H2SO4 + H2O2)P residual

30 mL NaHCO3

0,5 mol L-1Modifications:

- Microbial P was excluded

- NaOH 0,1 M + Sonification wassubstituted by NaOH 0,5M

- NaOH 0,5 M was introducedafter HCL extraction


Tiessen & Moir (2008)

Modifications:

- NaOH 0,5 M was substituted byHCL conc.


30 mL NaOH

0,1 mol L-1


extractPi-NaOH I


extract Pi-NH4Cl

extract Pi-NaHCO3

digestionPt-Pi =Po-NaHCO3

Pt-NaHCO3

0,5 g soil +30 mL NH4Cl

1 mol L-1



30 mL NaOH


extractPi-NaOH II


30 mL HCl

1 mol L-116h agitationcentrifugation

extractPi-HCl

Soil digestion (HNO3 + HCLO4)P residual

30 mL NaHCO3

0,5 mol L-1


Chen et al. (2000)

Modifications:

- Resin extraction wassubstituted by NH4CL 1 M

- NaOH 0,5 M was substituted byNaOH 0,1 M

- Perchloric digestion




III - Limitations


Presentation Parts


Hiper-manipulation of samples

LIMITATIONS (HEDLEY’S frac.)

Accumulative errors (sucessive extractions)

High complexity and Time consuming

Many modifications made by authors (low padronization)

Wet soil sample or dry soil sample?

Sieved soil (2,00mm) or Crushed soil (0,5mm)? (small soil samples)

Centrifugation: sandy soils: (3000 g) clayed soils (25000 g) (ultracentrifugation)


Separation of Pi and Po in NaOH and NaHCO3 (alkaline extracts)

extract Pi

Ptdigestion

Pt – Pi = Po

� Analysis of Pi immediately, because Po mineralization is continuos. (48h if at 4ºC)

� Dissolved Organic Matter interfers on the absorbance measure

Murphy & Rilley (1962) Prior to colorimetric reaction:

- Acidification until pH 1.5- Centrifugation or filtration in 0.45 μm

May occur co-precipitation of P

with DOM (30-50%)

May occurmineralization of Po

Dick & Tabatabai (1977) DOM Precipitation

occurs naturallyHigh toxity (NaAsO2)

Not occursmineralization of Po

Doesn’t work if pH >9.0(NaOH 0.5 M extracts)

Pyrophosphates aren’t detected


Separation of Pi and Po in NaOH and NaHCO3 (alkaline extracts)

extract Pi

Ptdigestion

Pt – Pi = Po

� Sulfuric digestion (digestion block)� Perchloric digestion (block/microwave)� Aqua regia digestion (block/microwave)� Pesulfate digestion (autoclave)

Murphy & Rilley (1962)

Method validationP solubilization from synthetic compounds, Co-solubilization of another ions, X-rays analysis, Spectroscopic analysis

Synthetic compounds behave like the similar soil

compounds?It's impossible predict all

physicochemical interactions that occur in the soil.

Limited selectivityof extratants:

Be carefull with

interpretation!


Changes in frac. protocol can affect markedly the results

NaOH 0.1 � NaOH 0.1 M � HCL 1 M or NaOH 0.1 � HCL 1 M � NaOH 0.1 M(affects directly the P-residual fraction)

Use of ANION RESIN without CATION RESIN overestimates the P-HCL fraction(P-Ca formed during alkaline extractions)

Washing the soil with NaCl after each extraction increase extraction(avoids neutralization of next extractant )

Be carefull with the “lability” of P forms

Many papers show that in specific conditions all P-forms are used by plants

First extractant:First extractant:Labile P

Final extractant:Final extractant:Recalcitrant P


Do not confuse:

Real Soil P-forms are:- Chemisorbed Pi (monodentate, bidentate and binuclear bond)

- Electrostatic Pi (Difuse double layer)

- Primary minerals Pi

- Soil Solution Pi

- Pyrophosphate Pi

- Monoester Po

- Diester Po

- Phosphonates Po

- Polyphosphates Po

- Microbial Po

P-FORMS FROM

FRACTIONATION ARE:

Pi-resin, Pi-NaHCO3, Po-NaHCO3, Pi-NaOH I, Po-

NaOH I, Pi-NaOH II, Po-NaOHII, Pi-HCl, P-residual




IV - Limitations


Presentation Parts


Main Uses:

- Soil phosphorus changes with weathering

- Soil phosphorus dynamics with fertilization

- Soil phosphorus changes with different plants

- Soil phosphorus changes with use of organic residues

- To identify forms of phosphorus absorbed by plants

- To identify forms of phosphorus acessed by extractants

- To identify forms of phosphorus in sediments

- To identify environmental riscs


Tiessen et al. (1984):

Low wheathered:86% of absorbed P from Pi

High wheathered:80% of absorbed P from Po

Guo & Yost (1998)

Cross & Schlesinger (1995)

...


If P balance (fertilization/exportation) is positive: only Pi is usedby plants

If balance is negative: all P forms (including recalcitrants) are used by plants

P dynamic with fertilization

Hedley et al. (1982)Beck & Sanches (1994)Guo & Yost. (1998)Blake et al. (2003)


Gatiboni et al. (2008)

0

500

1000

1500

2000

2500

PiRTA Pibic Pobic Pihid Pohid Pihid05 Pohid05 PiHCL Presidual

P forms

P,

mg

kg

-1

0 m3 ha

-1

20 m3 ha

-1

40 m3 ha

-1

P accumulation in a sandy soil with pig slurry use


Pavinato et al. (2009)

0-5 cm

P accumulation with fertilization in highly weathered soil

(Oxisol - Luziânia-Go)


Residual

NaOH II

NaOH I

NaHCO3

Resin

HCL

Residual

NaOH II

NaOH I

NaHCO3

Resin

HCL

After 15 sucessive extractions

with Mehlich 1After 15 sucessive extractions

with Anion resin

Extractants: Mode of action

Gatiboni et al. (2002)


Schimidt et al. (2012)

0-10 cm

30 years with High fertilization in a vineyard (Urusanga-SC)

0

5

10

15

20

25

30

35

40

Pi-RTA Pi-bic Po-bic Pi-hid Po-hid Pi-HCl Pi-hid5 Po-hid5 P-res

P, m

g/L

P forms

Campo nativo

vinhedo

Natural pasture

vineyard

P


NT Vs

CT

54

20

38

21

51

27

0,67

0,10

174

14485

80

49

21

38

16 118

74 91

45 36

34

69

51Rotation: vetch+oat/corn+cowpea

Depth 0-10cm

No tillage or Convention tillage: 18 years

Rheinheimer (2000)No tillage system

P


Availability of accumulated P in NT

+2% (15 crops)

(21)

(30)

(99)

(435)

(12)

(19)

(128)

-15%

(92)

NT: 10 years

Depth: 0-10cm

15 sucessive crops without P

Gatiboni (2003)

-32%

+61%+1%

+7% +32%

+13% -54%

-19% -61%

-37% -83%

-17%

+61%

+10%

-51%-23%

(35)

-43%(11ppm)

+10% (3 crops)


www.mpb.ou.edu

Current and future work:

Shoninger et al. (2012)

Colaborative work:

Gatiboni (UDESC); Pavinato (ESALQ);

Brunetto (UFSC); Calegari (IAPAR)

PPBMSBMS

Microbial Po

climosequence


P fractionation by Hedley´s procedure is a powerfultool for understanding the dynamics of soil phosphorus

The main benefit is to "see" beyond the phosphate extracted by routine methods.

but the limitations of the method should be considered to avoid erroneous conclusions.

Final Considerations


Fracionamento químico das formas de

fósforo do solo: usos e limitações

Gatiboni, L.C.; Brunetto, G., Rheinheimer,D.S.; Kaminski, J.

TÓPICOS EM CIÊNCIA DO SOLO, VOLUME VIII

LANÇAMENTO: FLORIANÓPOLIS, JULHO 2013 no CBCS


Thank you for your attention

[email protected]

Acknowledgements

fractionation of soil phosphorus by hedley’s procedure:...

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