• soil organic carbon - a trigger in the climate change...

KBUKommissionBodenschutzbeim

Conference: Soil, Climate Change and Biodiversity

Where do we stand?

• Soil Organic Carbon - a Trigger in the ClimateChange Process

Prof. Dr. Franz Makeschin

Chairman of the Soil Protection Commission

at the German Federal Environment Agency


Conference: Soil, Climate Change and Biodiversity – Where do we stand?Soil Organic Carbon - a Trigger in the Climate Change Process

Franz Makeschin

2

Global Carbon Cycle

Fluxes in Gt C a -1

Pools in Gt C

anthropogenic?? effects !!

Atmosphere

Fossile Pools

6.5122

60

+ 3.7 Gt/a

Plants

Soil

Marine

750

500

2 000

38 400

etwa 4 100

0.7

9090+ 1.8

after Bernhofer et al. 2007

62

60?

1



Franz Makeschin

3

C-Sequestration in Soil: State of knowledge

• Pools and changes of C-sequestration in soils are ratherunknown (esp. subsoils) !

Data from the Carbo-Europe-Project:

NBP (Soil) forest: 20 g m-2 a-1 (+/-60%)NBP (Soil) pasture: 57 g m-2 a-1 (+/- 130%)

NBP (Soil) arable land: -10 g m-2 a-1 (+/- 95%) (Schulze et al., 2008)

• Pools � Site specific with high variability!



Franz Makeschin

4

Organic matter and soil functions (ESS !)

Effects of different fractions

Soil Function / Parameter Correlation with organic C-Fractions fresh stable dissolved

Living space for Microorganisms + ++ (+) +/0

Storage of Nutrients (N>S>P) + ++ ++

Release of Nutrients + ++ +

Sorption of Cations (incl. HM) + (+) ++

Sorption of Organics + + ++

Shifting of Hazardous Compounds +/- - - - ++

Microbial Metabolism of Organics +/- ++ -

Aggregate Stability + ++ +

Erodibility + ++ (+)

Water Storage + ++ ++

C-Sequestration ++ - ++ 0



Franz Makeschin

5

Regional distribution of soil organic carbon in Europe

JRC-Map:

Organic carbon content(%) in the surface horizonof soils in Europe basedon the European Soil Data Base 1: 1 Mio.

http://eusoils.jrc.ec.europa.eu/ESDB_Archive/octop/octop_download.html



Franz Makeschin

6

1) Soil texture, parent material, climate (precipitation)……

BGRBGR

…...and topography form soil type patterns!



Franz Makeschin

7

2) Together will land use type (intensity?) an estimation of soil organic carbon is possible (ranges!!)

Düwel, et al., 2007

BGR



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Kartengrundlage: Nutzungsdifferenzierte Bodenübersichtskarte der Bundesrepublik Deutschland - BÜK 1000 N, BGR, Hannover 2007.

“Mountain / Hill” Cluster distinctive content of organic C(tcorg = 0,5)

“Clay”-Clusteraverage to distinctive content of organic C(tcorg = 0,31)

“Precipitation (Altitude)” Clusterdistinctive to superior content of organic C(tcorg = 0,77)

“Silt” Cluster average to distinctive content of organic C (tcorg = 0,32)

“Drought” Cluster

Very low contentof organic C(tcorg = -1,11)

“Warm” ClusterAverage content of organic C (tcorg = -0,04)

0 0,5 1-1 -0,5

+ ++-- - +/-

t-value scale for SOC

Clustering of influencing factors on SOC

UTERMANN 2009



Franz Makeschin

9

Gt CC-Pools in Surface Soils

(0-30 cm) in the EU

5.8 Gt C correspond to 27 years of the presentenergy-related CO2-emission of Germany

A reduction of the C-content of all German arable soils by 0.2 per centwould be equivalent to 48 per cent of the anualenergy-related CO2-emission of Germany



Franz Makeschin

10

C-inputs in soils: Option I

Internal C-resources

Harvest

Leaves & Wood

Rootresidues

Harvestbiomass

Rootresidues

Harvest residues ( e.g. straw)

Forests Cropland



Franz Makeschin

11

Cropland: Changes of SOC-content are influenced byfertilization

Dynamik des Kohlenstoffgehaltes in Abhängigkeit von der Düngung im Statischen Düngungsversuch Bad Lauchstädt

1902 1910 1920 1930 1940 1950 1960 1970 1980 1990 2000

1,4

1,6

1,8

2

2,2

2,430 t/ha Std.+NPK 30 t/ha Std. 20 t/ha Std.+NPK

20 t/ha Std. NPK ohne Düngung

r = 0,94**

r = 0,93**

r = 0,93**

r = 0,70*

Even extrem amounts of stable manure leads only to a

maximum change of 0,6 mass per cent SOC, in average to 0,4

per cent in Comparision to „humus consuming cultivation“

UFZ, Leipzig

Dynamic of C-Content due to Fertilization in the „Static FertilizationExperiment“ Bad Lauchstädt, Germany



Franz Makeschin

12

Cropland: Changes of SOC-content are influenced bymanagement

-2000

-1500

-1000

-500

0

500

1000ZuckerRüben Kartoffeln Mais Winterraps Getreide Sonnenblume Ackergras

Hu

mu

sbila

nz

in k

g C

ha-1

a-1

"VDLUFA untere Werte" Strohabfuhr

"VDLUFA untere Werte" Stroh bleibt

"VDLUFA obere Werte" Strohabfuhr

"VDLUFA obere Werte" Stroh bleibt

HE-ökologisch Strohabfuhr

HE-ökologisch Stroh bleibt

Different crops have different impacts via harvest and root residues(KBU 2008)

Car

bo

nb

alan

cekg

ha-

1 a-

1

Sugar beet Potato Corn W-rape Wheat Sunflower Grassland

> Straw removal

> Straw on field

> Straw removal

> Straw on field

> Straw removal

> Straw on field

Conventional

Organic



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Land Use Change

0 10 20 30 40 50Zeit [Jahre]

Ko

hle

nst

off

-Vo

rrat

Wald->AckerAcker->WaldAcker->Grünland

However: direction, slope and level of the (possible)development depend on several factors (predictability?) !

Car

bo

nS

tock __ Forest� Arable

__ Arable� Forest__ Arable� Grassland

Time (years)



Franz Makeschin

14Smith 2004

Conclusion:

Influence of

• texture

• cultivation (C-Qual.)

• water Balance

Important for assessment and modelling: time span !



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15

Regional challenges: recultivation of mining areas

• ~ 160.000 ha in lignitemining in Germany

• Dumping substrates areusually low in organicsubstances (except coalmoieties and ashes) withadverse physical und chemical properties

Question: Application of organic substances or slowdevelopment of organiccarbon by residues of growing plants?

Hüttl, 2001



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Conclusion: Storage and distribution of soil organiccarbon

• C-sequestration is depended on

- soil texture (clay content)- temperature- soil moisture (precipitation & ground water)- land use (arable << grassland </= forest)

• Principles are well understood but knowledge about impactof management systems is insecure

• Subsoil-C not very well known !

• Lack of regionalisation !



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Can we detect changes in SOC due to Climate Change sofar?

CAPRIEL and SEIFFERT, 2009

Field study Bavaria

Permanent monitoring sites (100 on cropland, 21 of grassland) 1986 to 2007

�indication of an average decrease of soil carbon of 3 per cent in cropland as well in grassland.

However:

Crops and fertilization are the main causesof the observed changes!

A climate effect could be neither provednor excluded !

The results in Bavaria are in line with thereported changes in soil organic matter in Austria, Belgium, France and England !



Franz Makeschin

18

Can we determine an „optimal“ SOC content?

low highContent in Soil

Suitable for the particular function

overall Corg

humified

degradable, high C/N

degradable,low C/N

Black carbon

C-sequestration

C-sequestration

Wettability

WettabilityFixation of hydrophob

hazardous compounds

N-supplyNitrate leaching

Fixation of haz. compoundsNutrient buffering (CEC)

Microbial activityNitrate leaching

Water retention capacity

Aggregation, erosion prevention



Franz Makeschin

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Conclusion: „optimal humus content“

• C-Sequestrierung is only one aspect! Crucial point: Whatare the effects to soil functions?

• For C-sequestrierung a maximal C-content would bepreferable!

• But: An optimal humus content has to support all soil functions!

• Optimal humus content cannot be determined only by Corg

C-soil functions prior-ranking to C-sequestration !



Franz Makeschin

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• Biowaste and artificial „Soil Improvers“• Long term C-Sequestration may be possible with

Compost HTC-coal Pyrolytic-coal

http://www.carboncommentary.com/2009/04/07/539Antoinetti

C-inputs in soils: Option II

Import of external C-ressources



Franz Makeschin

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Soil Improvers ! / ?

• Precaution: There are more hazardous compoundsin „waste“ (e.g. sewage sludge and compost) thanin harvest residues (evaluation: improving effectsvs accumulation of hazardous compounds

• New products like hydrothermale oder pyrolyticcoals promise long term C-Sequestration and/orimprovement of soil functions (experience?)

• If „new“ amendments do not show soil improvingeffects they should not be applied. Then a C-sequestration could better be conductet on a landfill or repository



Franz Makeschin

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Better alternatives & possible solutions:conservation of high value (organic) soils

• Protection of bogs, marshlands, fens (wetland sites)• Avoid ploughing / transfer of grassland to cropland• Keep good agricultural practice (e.g. crop rotation)• Soil protection measures by cultivation of energy crops• Afforestation??



Franz Makeschin

23

Reduce land consumption and sealing - Act Now !

Soil protection and renewable resources

Recommendations: Soil Protection Commission KBU

http://www.umweltbundesamt.de/boden-und-altlasten/boden/index.htm



Franz Makeschin

24

Bioeconomy Council Germany delivers its first

policy recommendations

http://www.biooekonomierat.de

Work group I: Soil

The major share of human food and biomass needed for materials and energy isproduced in the soil. The soil, as a finite geo-resource, but one which is also seriously endangered by sealing, erosion and degradation, is thus thecornerstone of the bio-economy.



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Soil Organic Carbon - a Trigger in theClimate Change Process



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A second challenge: assessment of global soil carbon(esp. developing and emerging countries)



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General conclusions: (Europe & international )

� Strong demand on data for soil assessment (CC, functions, ESS)

� Cross Compliance unsatisfactory (minimum requirements < GAP)

� Rio + 20 Process (Green Economy, Low Carbon Economy)

� Soils under stronger focus (CC, BioDiv, Desert Convention: up to

date or relict): protection of fertile soils under global view!

� Strong demand on pinpoint monitoring and continuous field

experiments !



Franz Makeschin

28

We need stronger footprints on / for soils!

Thank you for your attention!

• soil organic carbon - a trigger in the climate change...

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