Soil Organic Carbon Sequestration in the Southeastern USA: Alan J. Franzluebbers Ecologist Watkinsville GA TN MS AL GA FL VA NC SC MD Potential and Limitations.

Soil Organic Carbon Sequestration in the Southeastern USA:

Alan J.Franzluebbers

Ecologist

Watkinsville GA

TN

MSAL

GA

FL

VA

NC

SC

MD

Potential and Limitations

Soil Carbon Sequestration

Soil Organic Carbon (g . kg-1)

0 10 20 30 40 50 60

SoilDepth(cm)

-30

-20

-10

0

4-yr conventional tillage

Management Systems at Watkinsville GA

16-yr conservation tillage

4-yr conventional tillage

Management Systems at Watkinsville GA

15-yr tall fescue pasture

16-yr conservation tillage

4-yr conventional tillage

Management Systems at Watkinsville GA

Depth distribution of soil organic C

From Schnabel et al. (2001) Ch. 12, Pot. U.S. Grazing Lands Sequester C, Lewis Publ.

Data from Causarano et al. (2008) Soil Sci. Soc. Am. J. 72:221-230

Sequestration of SOC

(Mg ha-1 yr-1)--------------------

0.53 **

0.17 **

0.05 ns

0-20 cm0.74 **

Soil Carbon SequestrationCalculation by relative difference

0.15Mg C/ha/yr

0.00Mg C/ha/yr

Difference0.15

Mg C/ha/yr

0.15Mg C/ha/yr

-0.10Mg C/ha/yr

Difference0.25

Mg C/ha/yr

Soil Carbon SequestrationCalculation by change with time

Years of Management

0 25 50 75

SoilOrganicCarbon

(Mg . ha-1)

0

10

20

30

40

Conventionalagriculturefollowing

permanent cover

Conservationagriculture

Scenario A

Years of Management

0 25 50 75

SoilOrganicCarbon

(Mg . ha-1)

0

10

20

30

40

Conventionalagriculturefollowing

permanent cover

Conservationagriculture

Scenario A

0 25 50 75

Scenario B

Conventionalagriculture

for long history

Years of Management

0 25 50 75

SoilOrganicCarbon

(Mg . ha-1)

0

10

20

30

40

Conventionalagriculturefollowing

permanent cover

Conservationagriculture

Scenario A

0 25 50 75

Scenario B

0 25 50 75 100

Scenario C

Conventionalagriculture

for long history

Conventionaltillage

with adoption ofother best

managementpractices

0.15Mg C/ha/yr

0.10Mg C/ha/yr

Difference0.05

Mg C/ha/yr

Temporal and comparative approaches of value; in combination best!

Soil Carbon Sequestration

Franzluebbers et al. (2001) Soil Sci. Soc. Am. J. 65:834-841 and unpublished data

Years of Management

0 1 2 3 4 5 6 7 8

SoilOrganicCarbon

(Mg . ha-1)

12

14

16

18

20

22

24

Cut for hay

Years of Management

0 1 2 3 4 5 6 7 8

SoilOrganicCarbon

(Mg . ha-1)

12

14

16

18

20

22

24

Cut for hay

Unharvested

Years of Management

0 1 2 3 4 5 6 7 8

SoilOrganicCarbon

(Mg . ha-1)

12

14

16

18

20

22

24

Unharvested

Cut for hay

Lowgrazing pressure

Years of Management

0 1 2 3 4 5 6 7 8

SoilOrganicCarbon

(Mg . ha-1)

12

14

16

18

20

22

24

Unharvested

Cut for hay

Lowgrazing pressure

Highgrazing

pressure

Establishment of bermudagrass pasture following long-term cropping in Georgia USA (16 °C, 1250 mm)

Soil C sequestration

(Mg ha-1 yr-1) (0-5 yr):

--------------------------------Hayed 0.30

Unharvested 0.65

Grazed 1.40

Calculation by change with time

Soil Carbon SequestrationIn the USA and Canada, conservation-tillage cropping can sequester

an average of 0.33 Mg C/ha/yr

Data from Franzluebbers and Follett (2005) Soil Tillage Res. 83:1-8

Cold-dry region(6 °C, 400 mm)

0.27 + 0.19 Mg C/ha/yr

Northwest

Hot-dry region(18 °C, 265 mm)

0.30 + 0.21 Mg C/ha/yr

Southwest

Hot-wet region(20 °C, 1325 mm)

0.42 + 0.46 Mg C/ha/yr

Southeast

Cold-wet region(6 °C, 925 mm)

−0.07 + 0.27 Mg C/ha/yrNortheast

Mild region(12 °C, 930 mm)

0.48 + 0.59 Mg C/ha/yr

Central

Franzluebbers (2005) Soil Till. Res.

Soil Carbon SequestrationLiterature review from the

southeastern USA

Franzluebbers (2005) Soil Tillage Res. 83:120-147.

Franzluebbers (2005) Soil Till. Res.

Soil Carbon SequestrationLiterature review from the

southeastern USA

Franzluebbers (2005) Soil Tillage Res. 83:120-147.

Soil Carbon Sequestration

Soil Organic Carbon Sequestrationin the Southeastern USA

----------------------------------------------------

0.28 + 0.44 Mg C/ha/yr(without cover cropping)

0.53 + 0.45 Mg C/ha/yr(with cover cropping)

Franzluebbers (2005) Soil Tillage Res. 83:120-147.

Photos of 2 no-tillage systems in Virginia USA

Impact of cover cropping in the southeastern USA

Soil Carbon SequestrationStratification ratio of soil organic C

Franzluebbers (2002) Soil Till. Res. 66:95-106

Soil Carbon SequestrationStratification ratio of soil organic C

Data from Causarano et al. (2008) Soil Sci. Soc. Am. J. 72:221-230

Influence of tillage system following pasture

Franzluebbers and Stuedemann (2008) Soil Sci. Soc. Am. J. 72:613-625

Soil Organic C (g . kg-1)

0 10 20 30 40

SoilDepth(cm)

-20

-10

0

Initiation

-30

-20

-10

0

At end of 3 years

Conventional tillage

No tillage

Starting from long-term pasture condition

Soil Carbon Sequestration

Years of Management

0 1 2 3

0-12 cm

CT vs NT ***

Years of Management

0 1 2 3 4

0-20 cm

CT vs NT **

0 1 2 3

TotalOrganicCarbon

(Mg . ha-1)

0

10

20

30

40

50

Years of Management

0-6 cm

CT vs NT ***

Pasture

No tillage (NT)Conventional tillage (CT)

Franzluebbers and Stuedemann (2008) Soil Sci. Soc. Am. J. 72:613-625

∆ SOC = −1.54 Mg/ha/yr

∆ SOC = 0.19 Mg/ha/yr

Soil Carbon SequestrationInfluence of tillage system following pasture

Temperate or frigid regions (23 + 15%)

Thermic regions (7 + 5%)

Moist regions (8 + 4%)

Dry regions (11 + 14%)

Percentage of carbon applied as manure retained in soil(review of literature in 2001)

Soil Carbon SequestrationInfluence of animal manure application dependent on climate

Opportunities exist to capture more carbon from crop and grazing systems when the two systems are integrated:

Soil Carbon Sequestration

Utilization of ligno-cellulosic plant materials by ruminants

Manure deposition directly on land

Weeds can be managed with management rather than chemicals

Integration of crops and livestock

Franzluebbers and Stuedemann (2008)Soil Sci. Soc. Am. J. 72:613-625

Soil Carbon Sequestration

Years

0 1 2 3

TotalOrganicCarbon

(Mg . ha-1)

10

15

20

25

Grazed

Ungrazed

Franzluebbers and Stuedemann (2008) Soil Sci. Soc. Am. J. 72:613-625Years

0 1 2 3

SoilMicrobialBiomassCarbon

(kg . ha-1)

400

600

800

1000

Grazed

Ungrazed

*

Years

0 1 2 3

NetNitrogen

Mineralization(kg . ha-1 [24 d]-1)

40

60

80

100

Grazed

Ungrazed

*

Grazing of cover crops under no tillage (0-6 cm)

Franzluebbers (2005) Soil Tillage Res. 83:120-147

Nitrogen Fertilization (kg . ha-1 . yr-1)

0 100 200 300

Changein

SoilOrganicCarbon

(Mg . ha-1 . yr-1)

0.0

0.4

0.8

1.2

1.6

Conventional Tillage

Nitrogen Fertilization (kg . ha-1 . yr-1)

0 100 200 300

Changein

SoilOrganicCarbon

(Mg . ha-1 . yr-1)

0.0

0.4

0.8

1.2

1.6

Conventional Tillage

No Tillage

Nitrogen Fertilization (kg . ha-1 . yr-1)

0 100 200 300

Changein

SoilOrganicCarbon

(Mg . ha-1 . yr-1)

0.0

0.4

0.8

1.2

1.6

Conventional Tillage

No Tillage

Carbon cost ofN fertilizer

(0.98 to 2.82 kg C . kg-1 N)

Nitrogen Fertilization (kg . ha-1 . yr-1)

0 100 200 300

Changein

SoilOrganicCarbon

(Mg . ha-1 . yr-1)

0.0

0.4

0.8

1.2

1.6

Conventional Tillage

No Tillage

Carbon cost ofN fertilizer

(0.98 to 2.82 kg C . kg-1 N)

Soil Carbon SequestrationNitrogen fertilization effect

1 kg N2O-N ha-1

=0.13 Mg C ha-1

Nitrous Oxide EmissionInteraction of tillage with soil type

Rochette (2008) Soil Till. Res. 101:97-100

Soil Aeration

N2O

Emission(kg N . ha-1)

0

1

2

3

4

5

6

7

8

Good Medium

Conventional tillage

No tillage

Poor

p = 0.06

45 site-years of data reviewedBrazil, Canada, France, Japan,New Zealand, United Kingdom, USA

Franzluebbers and Brock (2007)Soil Till. Res. 93:126-137

Response

0-20-cm depth

Silage Crop Removal

Initially 0.5 yr-1 1-2 yr-1

At end of 7 years

Bulk density (Mg m-3) 1.43 1.37 ns 1.39

Macroaggregate stability (g g-1) 0.74 0.87 * 0.81

Soil organic C (mg g-1) 11.7 14.3 * 12.5

Soil Carbon SequestrationInfluence of crop residue removal

On-farm researchNorth Carolina PiedmontCorn silage each year vs corn silage less often

Data from Sharpley and Kleinman (2003) J. Environ. Qual. 32:2172-2179and Sharpley and Smith (1994) Soil Tillage Res. 30:33-48

Total PDissolved PSediment

Runoff loss (kg/ha)Soil (g/kg – 0-5 cm depth)

Grass

NT crop

CT crop

Mehlich-3 POrganic C

Land use

0.19

0.27

0.52

0.03

0.03

0.02

104

312

767

0.40

0.33

0.32

16.6

25.2

13.7

Oklahoma

Runoff loss (kg/ha/yr)

Grass

NT wheat

CT wheat

Total PDissolved P

Total NNitrate NSediment

Water runoff

(mm/yr)

Land use

Pennsylvania

0.1

1.4

2.8

0.1

0.7

0.2

1.2

7.2

15.0

0.1

1.4

1.3

100

625

6515

48

111

61

Off-Site ImpactsWater quality implications

ca. 30% of total CH4 emission in USA is from agriculture (US-EPA, 2007)

Assumptions: 0.15 + 0.08 kg CH4 head-1 d-1 [Harper et al. (1999) J. Anim. Sci. 77:1392-1401]

19 Mha of pasture land in southeastern USA (USDA-NASS, 1997)

12 million head of cattle in southeastern USA (USDA-NASS, 1997)

Resulting in: 0.62 head ha-1 34 kg CH4 ha-1 yr-1

0.37 to 1.20 Mg CO2-C equivalent ha-1 yr-1

Agriculture’s contribution to greenhouse gas emissions reviewed:Johnson et al. (2007) Environ. Poll. 150:107-124

Methane Emission

Soil Carbon SequestrationSummary

Soil organic carbon can be sequestered with adoption of conservation agricultural practices

Enhanced soil fertility and soil quality

Mitigation of greenhouse gas emissions

Soil surface change is most notable

Long-term changes are most scientifically defensible

Soil Carbon SequestrationAcknowledgements

FundingAgricultural Research Service

(ARS)US-Department of EnergyMadison County Cattleman’s

AssociationUSDA-National Research

Initiative – Soil ProcessesCotton IncorporatedGeorgia Commodity

Commission for CornThe Organic CenterARS GRACEnet team