Josan

Manure-component Effects on P Release from Manure-amended

Sandy Soils

M. S. Josan

IntroductionIntroduction

Active and abandoned dairiesActive and abandoned dairies

Continuous release of P from these soils Continuous release of P from these soils even years after abandonment (Nair et al., even years after abandonment (Nair et al., 2003)2003)

Paucity of P retaining mineralsPaucity of P retaining minerals

Manure components are important in the Manure components are important in the fate of P in dairy manure-impacted soilsfate of P in dairy manure-impacted soils

Importance of Mg in P dynamics in these Importance of Mg in P dynamics in these soils has not been recognizedsoils has not been recognized

Properties of Manure Impacted Properties of Manure Impacted and Unimpacted Soilsand Unimpacted Soils

Impacted Unimpacted

pH 6.7-7.5

EC (dS m-1) 0.4-0.8

Total Ca (mg kg-1) 3200-8400

Total Mg (mg kg-1) 700-2100

Total P (mg kg-1) 1000-3200

Total Fe (mg kg-1) 190 – 1200

Total Al (mg kg-1) 300 - 4000

Impacted Unimpacted

pH 6.7-7.5 3.8 - 5.0

EC (dS m-1) 0.4-0.8 0.07 – 0.20

Total Ca (mg kg-1) 3200-8400 50 – 640

Total Mg (mg kg-1) 700-2100 10 – 50

Total P (mg kg-1) 1000-3200 58 – 190

Total Fe (mg kg-1) 190 – 1200 300 – 1800

Total Al (mg kg-1) 300 - 4000 120 - 1138

RationaleRationale

High Ca concentrations and pH should High Ca concentrations and pH should favor the formation of relatively stable favor the formation of relatively stable calcium phosphatescalcium phosphates

Stable Ca-P minerals (such as apatite) Stable Ca-P minerals (such as apatite) have not been found in heavy manure-have not been found in heavy manure-impacted soils (Wang et al. 1995)impacted soils (Wang et al. 1995)

Non-formation of Ca-P minerals could be Non-formation of Ca-P minerals could be due to inhibition by Mg, biogenic Si, and due to inhibition by Mg, biogenic Si, and DOCDOC

HypothesesHypotheses

The release of phosphorus (P) in dairy The release of phosphorus (P) in dairy

manure-impacted soils is controlled by manure-impacted soils is controlled by

sparingly soluble Ca and/or Mg-sparingly soluble Ca and/or Mg-

phosphate phasesphosphate phases

Magnesium phosphate is a manure Magnesium phosphate is a manure

component rather than a component component rather than a component

formed in soil after manure applicationformed in soil after manure application

ObjectivesObjectives

Assess the release of Ca, Mg and P in Assess the release of Ca, Mg and P in soil solution from dairy manure-soil solution from dairy manure-impacted soilsimpacted soils

Evaluate Ca and/or Mg-P association in Evaluate Ca and/or Mg-P association in dairy manure and manure-impacted dairy manure and manure-impacted soilssoils

Materials and MethodsMaterials and Methods

Soil and manure samplingSoil and manure sampling

Particle size fractionation and chemical Particle size fractionation and chemical characterization of soil and manure samplescharacterization of soil and manure samples

Repeated water Repeated water extractionsextractions

Column leachingColumn leaching

Materials and MethodsMaterials and Methods

Chemical equilibrium modeling (V-Chemical equilibrium modeling (V-MINTEQ)MINTEQ)

– Soil and dairy manure column Soil and dairy manure column effluentseffluents

– Saturation paste extractsSaturation paste extracts

Chemical fractionationChemical fractionation

Josan

Fractionation Scheme

Soil (2g)

NH4Cl-P

20 mL 1M NH4Cl

2-h shaking

Labile -P

Total P

Org. –P=

(Total P- In -P) Nair et al., 1995

NaOH-P

20 mL 0.1M NaOH

17-h shaking

Fe/Al -P

HCl-P

20 mL 0.5M HCl

24-h shaking

Ca/Mg -P

Residual-P

Ignition at 550o C

Acid solubilization

Mainly organic -P

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Percentage of P Fractions in A-horizon of a Heavily Manure-impacted soil

(TP= 2900 mg kg-1) 1st NH4Cl Extraction10%

69%

3%

10%

8%

Ca/Mg -PN

H4C

l -P

Resid

ual -P

Al/Fe -POrg. -P

Hieltjes and Lijklema (1980)

Nair et al. (1995)

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Percentage of P Fractions in A-horizon of a Heavily Manure-impacted soil

(TP= 2900 mg kg-1) 2nd NH4Cl Extraction

20%

59%

3%

10%

8%

Ca/Mg -P

Resid

ual -P

NH4Cl -PAl/Fe -POrg. -P

Josan

Percentage of P Fractions in A-horizon of a Heavily Manure-impacted soil

(TP= 2900 mg kg-1) 3rd NH4Cl Extraction

35%

44%

3%

10%

8%

Ca/Mg -P

Resid

ual -P

NH4Cl -PAl/Fe -POrg. -P

Josan

Percentage of P Fractions in A-horizon of a Heavily Manure-impacted soil

(TP= 2900 mg kg-1) ‘n’ Extractions

70%

9%

3%

10%

8%

Ca/Mg -P

Resid

ual -P

NH4Cl -P

Al/Fe -POrg. -P

Josan

Modified Fractionation Scheme

Soil (2g)

NH4Cl-P

20 mL 1M NH4Cl

2-h shaking

1st Extraction

NH4Cl-P

20 mL 1M NH4Cl

2-h shaking

10th Extraction or Greater

NH4Cl-P

20 mL 1M NH4Cl

2-h shaking

2nd Extraction

NH4Cl-P

20 mL 1M NH4Cl

2-h shaking

3rd Extraction

Residual-P

Ignition at 550o C

Acid solubilization

NaOH-P

20 mL 0.1M NaOH

17-h shaking

HCl-P

20 mL 0.5M HCl

24-h shaking

• Ca, Mg, and P concentrations will be determined in each extraction

Materials and MethodsMaterials and Methods

Solid state assessments: Solid state assessments:

– Density separationDensity separation

– X-ray diffraction (X-ray diffraction (XRD) XRD)

– Thermogravimetery (Thermogravimetery (TG) TG)

– Scanning electron microscopy (Scanning electron microscopy (SEM) SEM)

and Energy dispersive X-ray analysis and Energy dispersive X-ray analysis

(EDS)(EDS)

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Solid State Assessment

XRD

TG

SEM

Air-dried soil Air-dried manure

Particle size fractionation and pre-concentration

? P with Mg or Ca

Density separation

<2.0 g cm-3

>2.0 g cm-3

Density separation

<2.0 g cm-3

>2.0 g cm-3

Silt Clay

Statistical Analysis Statistical Analysis

Analysis of variance (ANOVA)Analysis of variance (ANOVA)

– The Student-Newman-KeulsThe Student-Newman-Keuls

Non-parametric statistics (the Kruskal-Non-parametric statistics (the Kruskal-

Wallis test)Wallis test)

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Preliminary Results

Josan

SRP, Mg and Ca Relationships for Active Dairy Manure Soils during Repeated Water Extractions

Josan et al. 2005 (in press)

y = 1.98x - 3.81

r 2 = 0.68 (Mg)

y = -0.19x + 79.4

r 2 = 0.01 (Ca)

0

20

40

60

80

100

120

140

160

0 20 40 60 80 100 120 140Mg or Ca (mg kg-1)

SR

P (

mg

kg-1

)

Mg Ca

Josan

SRP, Mg and Ca Relationships for Abandoned Dairy Manure Soils during Repeated Water Extractions

Josan et al. 2005 (in press)

y = 1.19x + 10.83

r 2 = 0.62 (Mg)

y = 0.45x + 21.0

r 2 = 0.20 (Ca)

0

20

40

60

80

100

120

140

0 20 40 60 80 100 120 140Mg or Ca (mg kg-1)

SRP

(mg

kg-1

)

Mg Ca

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Speciation Data from Column Leachates

Mineral

PhaseFormula

Active Abandoned

(SI = log IAP - log Ksp)

Struvite (NH4MgPO4·6H2O) -0.28 -1.63

Farringtonite Mg3(PO4)2 -1.03 -1.68

Newberryite MgHPO4·3H2O -0.60 -0.86

Monetite CaHPO4 0.17 0.54

Brushite CaHPO4·2H2O -0.11 0.26

Hydroxyapatite [Ca5(PO4)3 (OH)] 12.84 12.16

Josan et al. 2005 (in press)

Dot Map Images of Dairy Manure Dot Map Images of Dairy Manure Clay Size FractionClay Size Fraction

Expected Results and Implications Expected Results and Implications

P stabilization via crystallization of calcium P stabilization via crystallization of calcium phosphates (even at near-neutral pH) may be phosphates (even at near-neutral pH) may be preempted by Mg-P associationpreempted by Mg-P association

Mg-P association is a key factor for high P Mg-P association is a key factor for high P activities in these soilsactivities in these soils

Approaches to minimize P releaseApproaches to minimize P release– P-retaining soil amendments P-retaining soil amendments – Management of animal diet to eliminate Mg-P Management of animal diet to eliminate Mg-P

formation. formation.

AcknowledgmentsAcknowledgmentsSupported in part by the USDA-NRI Supported in part by the USDA-NRI Committee MembersCommittee Members– Dr. Vimala Nair (Chair)Dr. Vimala Nair (Chair)– Dr. Willie HarrisDr. Willie Harris– Dr. George O’ConnorDr. George O’Connor– Dr. Dean RhueDr. Dean Rhue– Dr. Tom ObrezaDr. Tom Obreza– Dr. Amelia Dempere (Materials Science & Dr. Amelia Dempere (Materials Science &

Engineering Department)Engineering Department)

Thanks are also due to several people in SWSD Thanks are also due to several people in SWSD who have helped me since my joining the who have helped me since my joining the departmentdepartment

Comments and SuggestionsComments and Suggestions

ThanksThanks