Carbon sequestration potential of soils in southeast Germany derived from stable soil organic carbon saturation

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  • Carbon sequestration potential of soils in southeastGermany derived from stable soil organic carbonsaturationMART IN WIESME IER * , R ICO HUBNER , P ETER SP ORLE IN , UWE GEU ,

    EDZARD HANGEN , ARTHUR RE I SCHL , B ERND SCH ILL ING , MARG IT VON L UTZOW*

    and INGRID K OGEL-KNABNER*

    *Lehrstuhl fur Bodenkunde, Department fur Okologie und Okosystemmanagement, Wissenschaftszentrum Weihenstephan fur

    Ernahrung, Landnutzung und Umwelt, Technische Universitat Munchen, Freising-Weihenstephan 85350, Germany, Lehrstuhl

    fur Wirtschaftslehre des Landbaues, Wissenschaftszentrum Weihenstephan fur Ernahrung, Landnutzung und Umwelt, Technische

    Universitat Munchen, Freising-Weihenstephan 85350, Germany, Bavarian Environment Agency, Hof 95030, Germany,

    Institute for Advanced Study, Technische Universitat Munchen, Garching 85748, Germany

    Abstract

    Sequestration of atmospheric carbon (C) in soils through improved management of forest and agricultural land is

    considered to have high potential for global CO2 mitigation. However, the potential of soils to sequester soil organic

    carbon (SOC) in a stable form, which is limited by the stabilization of SOC against microbial mineralization, is largely

    unknown. In this study, we estimated the C sequestration potential of soils in southeast Germany by calculating the

    potential SOC saturation of silt and clay particles according to Hassink [Plant and Soil 191 (1997) 77] on the basis of

    516 soil profiles. The determination of the current SOC content of silt and clay fractions for major soil units and land

    uses allowed an estimation of the C saturation deficit corresponding to the long-term C sequestration potential. The

    results showed that cropland soils have a low level of C saturation of around 50% and could store considerable

    amounts of additional SOC. A relatively high C sequestration potential was also determined for grassland soils. In

    contrast, forest soils had a low C sequestration potential as they were almost C saturated. A high proportion of sites

    with a high degree of apparent oversaturation revealed that in acidic, coarse-textured soils the relation to silt and clay

    is not suitable to estimate the stable C saturation. A strong correlation of the C saturation deficit with temperature

    and precipitation allowed a spatial estimation of the C sequestration potential for Bavaria. In total, about 395 Mt

    CO2-equivalents could theoretically be stored in A horizons of cultivated soils four times the annual emission ofgreenhouse gases in Bavaria. Although achieving the entire estimated C storage capacity is unrealistic, improved

    management of cultivated land could contribute significantly to CO2 mitigation. Moreover, increasing SOC stocks

    have additional benefits with respect to enhanced soil fertility and agricultural productivity.

    Keywords: agricultural management, climate change, CO2 mitigation, soil organic carbon stocks, soil fractionation, stabilization

    of soil organic matter

    Received 18 April 2013 and accepted 30 August 2013

    Introduction

    Sequestration of atmospheric carbon (C) in soils is

    considered to contribute significantly to CO2 mitiga-

    tion, and several management options for increasing

    SOC stocks have been discussed. For forest ecosystems,

    practices such as a change in tree species composition,

    afforestation, thinning, drainage, fertilization, liming,

    site preparation and harvest management are associ-

    ated with an increase in SOC stocks and are conse-

    quently viewed as having a high potential for soil C

    sequestration (Goodale et al., 2002; Liski et al., 2002;

    Karjalainen et al., 2003; Lal, 2005; Jandl et al., 2007; Ciais

    et al., 2008; Lorenz & Lal, 2010; Luyssaert et al., 2010;

    Carroll et al., 2012; Vesterdal et al., 2012; Wiesmeier

    et al., 2013b). An even higher C sequestration potential

    is assumed for agricultural soils because a distinct

    depletion of SOC stocks has been observed in most

    cultivated soils (Paustian et al., 1997; Lal, 2004; Smith,

    2004). Among several agricultural practices that may

    increase C sequestration in cultivated soils, promising

    management options are promotion of organic inputs,

    conservation/zero tillage, converting cropland to grass-

    land, introduction of perennials, improved manage-

    ment of farmed peatland and organic farming (Cole

    et al., 1997; Paustian et al., 2000; Sauerbeck, 2001; Vlees-

    houwers & Verhagen, 2002; Freibauer et al., 2004; Hol-

    land, 2004; Lal, 2004; Johnson et al., 2007; Smith, 2012).Correspondence: Martin Wiesmeier, tel. +49 (0)8161 71 3679,

    fax +49 (0)8161 71 4466, e-mail: wiesmeier@wzw.tum.de

    2013 John Wiley & Sons Ltd 653

    Global Change Biology (2014) 20, 653665, doi: 10.1111/gcb.12384

  • However, C sequestration by improved management

    of forest and agricultural soils reaches a new equilib-

    rium at a higher SOC level after a certain period of

    time. Several studies have shown that there is an upper

    limit of SOC storage, confirming the hypothesis of soil

    C saturation (Six et al., 2002; Goh, 2004; Stewart et al.,

    2007, 2008; Chung et al., 2008). This is related to the lim-

    ited potential of soils to stabilize soil organic matter

    (SOM) against microbial mineralization (Baldock &

    Skjemstad, 2000). There are three major SOM stabiliza-

    tion mechanisms: selective preservation due to recalci-

    trance of SOM, spatial inaccessibility of SOM due to

    hydrophobicity or occlusion in soil aggregates, and

    interaction with mineral surfaces (Sollins et al., 1996;

    von Lutzow et al., 2006). The last is regarded as quanti-

    tatively the most important in a wide range of soils, as

    indicated by a strong correlation of SOC stocks with

    clay contents (e.g. Oades, 1988; Arrouays et al., 2006).

    Hassink (1997) assumed that the capacity of soils to

    preserve SOC is limited by the proportion of silt and

    clay particles (fine fraction

  • main land uses were adequately represented, with 115 loca-

    tions (22% of the data) as cropland (34% of the total area), 110

    locations (21%) as grassland (16%), 249 locations (48%) as

    forest (35%) and 42 locations (8%) under other land uses

    (15%). The main part of the data constituted a grid sampling

    within Bavaria (Joneck et al., 2006). Between 2000 and 2004,

    soil profiles were sampled using grids of 8 9 8 km within

    Bavaria. For each soil profile, a representative location was

    selected within a radius of 500 m around the grid node to

    achieve a homogeneous sampling area in terms of vegetation,

    relief, soil type and parent material as well as a central posi-

    tion in the particular land use type. Anthropogenic distur-

    bances in the subsoil were excluded in a pre-exploratory

    survey using a soil auger. Topsoil material was collected as a

    composite sample from eight sub-locations around one main

    soil profile to cover the small-scale heterogeneity of the soils.

    At the main soil profile, steel core samples with a diameter of

    10 cm were extracted for topsoil horizons. A small number of

    soil profiles originated from permanent soil monitoring sites

    (Schubert, 2002) and other regional soil surveys.

    Determination of soil properties

    The proportion of SOC stored in the fraction

  • and curvature were determined. As secondary parameters,

    the contributing area (CA) and the topographic wetness index

    (TWI) were calculated using the following equation:

    TWI ln CAtan a

    4

    where CA is the specific upslope contributing area derived by

    a geographical information system and a is the slope. The TWIis a topographical variable that indicates soil moisture condi-

    tions (Beven & Kirkby, 1978; Sorensen et al., 2006). To include

    geology as a potential parameter influencing the C saturation,

    parent material data were assigned from a map with 35 parent

    material classes (BAG500) with a resolution of 2 km from the

    Bavarian Environment Agency. Information about the soil type

    was included using a generalized soil map (BUK1000N) with

    28 superior soil classes (Leitbodenassoziationen) with a resolu-

    tion of 2 km from the Federal Institute for Geosciences and

    Natural Resources. The factor land use was incorporated by

    using 2006 satellite data from the CORINE Land Cover project

    (CLC2006) from the German Remote Sensing Data Center. For

    climatic variables, annual precipitation and mean annual tem-

    perature determined between 1981 and 2010 by the German

    Weather Service with a resolution of 1 km were allocated. All

    environmental parameters were assigned to 25 9 25 m cells.

    Statistical analysis

    Descriptive statistics were applied to describe the soil data sets

    including mean, minimum and maximum values, median,

    interquartile range, extremes and outliers, skewness and kur-

    tosis. In order to scale current C concentrations of the fine frac-

    tion 100 cm; 2 = 95100 cm;3 = 9095 cm; 4 =

  • fraction, which was calculated according to the equa-

    tion of Hassink (1997), was also similar between land

    uses and ranged between 19.7 and 20.8 mg g1.The current C concentration of the fine fraction was

    measured for soils under major land uses in Bavaria

    (Fig. 1). For cropland soils, the proportion of OC

    stored in the fraction

  • with the proportion of the fine fraction, particularly

    in cropland soils (Fig. 4). In contrast, forest soils and

    soils under other land uses showed no significant

    relationship with the fine fraction content. To gain

    insight into the factors that control the C sequestration

    potential, correlations between several environmental

    Fig. 2 Correlation between the proportion of particles

  • parameters and the C saturation deficit were examined

    (Table 3). Strong positive correlations (P < 0.01) werefound with mean annual temperature and pH and

    strong negative correlations (P < 0.01) with annual pre-cipitation, elevation, slope and soil class. However, a

    multiple linear regression analysis that included two

    factors derived from a PCA (Table 4) revealed that the

    C saturation deficit was strongly controlled by one fac-

    tor that showed high loadings of temperature, precipi-

    tation and elevation.

    Fig. 4 Correlation between proportion of particles

  • Discussion

    The C saturation deficit of agricultural soils

    The estimation of the C saturation deficit in soils of

    Bavaria revealed that it was dependent on the current

    C content of the fine fraction. The potential C saturation

    as a function of the proportion of particles

  • compared with cropland soils. This is in the range

    reported for pastures in the south-eastern United

    States, where a silt- and clay-associated C saturation of

    60% was determined (Conant et al., 2003). A higher C

    saturation in pastures compared with cropland was

    also detected in Australia, though on a lower C satura-

    tion level (Chan, 2001).

    In summary, both cropland and grassland soils in

    Bavaria have a substantial potential to sequester addi-

    tional amounts of C in a stable form. A positive rela-

    tionship of the C saturation deficit with the silt and clay

    content (Fig. 4) revealed that soils that are particularly

    fine textured have a large potential for C sequestration.

    C saturation in forest soils and limitations of Hassinksequation

    In forest soils, a distinctly different level of C saturation

    in the fine fraction was observed as compared with

    agricultural soils. The current C concentration

    increased slightly with the proportion of particles

  • degraded grasslands worldwide (Conant & Paustian,

    2002). For each land use, thresholds of temperature and

    precipitation were derived (point of intersection of the

    regression line at a C saturation deficit of 0) that divide

    the areas of the respective land uses into regions with

    saturated and unsaturated conditions (Table 5). The C

    sequestration potential for each land use was estimated

    by multiplying the area of unsaturated conditions by

    the median value of the C saturation deficit of this area.

    A regionalization of the C sequestration potential using

    geostatistical methods was not conducted as the C satu-

    ration deficit of the investigated locations was calcu-

    lated using only an estimation of the current C

    saturation of the fine fraction, which was based on a

    smaller data set.

    The results revealed that cropland and grassland

    soils of Bavaria could potentially sequester 32 and 6 Mt

    C in the uppermost 10 cm respectively. The high poten-

    tial of cropland soils is related to the high C saturation

    deficit of intensively cultivated soils and a large area

    with unsaturated conditions. Less than 1% of the total

    cropland area of Bavaria was assigned to saturated

    conditions as cultivation is not feasible in cool, humid

    areas. For forest soils, a C sequestration potential of

    only 4 Mt was estimated with a high uncertainty as

    previously explained. Other land uses have a potential

    to sequester 9 Mt C. The low potential of forest soils to

    sequester C can be ascribed to almost saturated condi-

    tions in forest soils and the fact that only half of the

    total forest area was associated with unsaturated condi-

    tions. About 50% of Bavarian forests are located in

    regions where cool, humid conditions result in a

    complete C saturation of silt and clay particles.

    The C sequestration potential estimated for the first

    10 cm of the soil was extrapolated to the median depth

    of A horizons of each land use, assuming that soil

    texture and SOC contents are comparable within the A

    horizon. The C sequestration potential of A horizons

    under cropland, grassland, forest and other uses was

    estimated to be 96, 12, 4 and 22 Mt respectively. In total,

    soils of Bavaria could additionally sequester 134 Mt C,

    18% of total SOC stocks of 764 Mt. This amount corre-

    sponds to 490 Mt CO2-equivalents (CO2-eq.), which is

    more than five times higher than the annual greenhouse

    gas emission (in 2009) in Bavaria of 94 Mt CO2-eq.

    (UGRdL, 2012). The majority, 395 Mt CO2-eq.

    Fig. 5 Correlation between mean annual temperature and the C saturation deficit (Csat-def) for cropland (C), grassland (G), forest (F)

    and other land uses (O). Values above the dashed line refer to a deficit of C saturation, values below the dashed line refer to an oversat-

    uration of C.

    2013 John Wiley & Sons Ltd, Global Change Biology, 20, 653665

    662 M. WIESMEIER et al.

  • (approximately 80%), could be sequestered in agricul-

    tural soils. An increase in C saturation in forest soils

    and soils under other land uses is associated with high

    uncertainty. Assuming that due to an improved man-

    agement of cultivated soils the theoretical stable C stor-

    age potential is reached after a mean period of 30 years

    (West & Six, 2007), a mean annual amount of 13 Mt

    CO2-eq. could be sequestered in Bavarian soils over this

    period of time, which is 14% of the annual emission of

    greenhouse gases in Bavaria (in 2009). On an area basis,

    4.1 t CO2-eq. ha1 yr1 could potentially be seques-

    tered in agricultural soils, which is considerably higher

    than observed and modelled C accumulation rates

    through various management options aimed at increas-

    ing SOC stocks in cultivated soils (Vleeshouwers &

    Verhagen, 2002; West & Post, 2002; Freibauer et al.,

    2004; Smith et al., 2008).

    Outlook

    A comparison of the current C amount with the poten-

    tial C saturation of silt and clay particles according to

    Hassink (1997) revealed high C sequestration potential

    of agricultural topsoils in Bavaria. Although there are

    some large uncertainties regarding the efficiency and

    practicability of proposed management options to

    Fig. 6 Correlation between annual precipitation and the C saturation deficit (Csat-def) for cropland (C), grassland (G), forest (F) and

    other land uses (O). Values above the dashed line refer to a deficit of C saturation, values below the dashed line refer to an oversatura-

    tion of C.

    Table 5 Threshold of mean annual temperature (MATunsat) and annual precipitation (MAPunsat) for unsaturated soils, area of satu-

    rated (Areasat) and unsaturated (Areaunsat) soils, C sequestration potential to a depth of 10 cm (Cseq-0-10) and extrapolated for the A

    horizon (Cseq-A) for different land uses within Bavaria

    MATunsat (C) MAPunsat (mm) Areasat (km2) Areaunsat (km

    2) Cseq (t ha1) Cseq-0-10 (Mt) Cseq-A (Mt)

    Cropland (C) >6.4 7.0 8.1 8.0

  • increase SOC stocks, the estimated high potential of

    agricultural soils for C sequestration justifies optimized

    SOM management of cultivated soils. One has to bear

    in mind that besides the stable C sequestration in the

    fine fraction, a significant additional amount of labile

    SOC will also be sequestered as a result of improved

    agricultural management. Furthermore, it is important

    to note that there are benefits associated with C seques-

    tration beyond CO2 mitigation because increased SOM

    is associated with improved soil fertility, soil structure,

    water holding capacity and thus a higher productivity.

    Further important aspects are reduced risk of soil

    erosion, decreased eutrophication and water contami-

    nation as well as reduced costs for fossil fuel and fertil-

    izer inputs (Paustian et al., 1998; Lal, 2007). Further

    studies are needed to connect the estimated C seques-

    tration potential of Bavarian soils with the economical

    and political feasibility of agricultural practices aimed

    at increasing SOC stocks. Such considerations should

    include not only the possible range of CO2 mitigation,

    but also additional benefits of SOM increases such as

    improved soil fertility and productivity.

    Acknowledgements

    We thank Alfred Schubert from the Bavarian State Institute forForestry for providing forest soil data. Ulrike Maul, NadineEheim, Wiebke Wehrmann and Sigrid Hiesch are acknowledgedfor laboratory work. We are grateful to the Bavarian State Minis-try of the Environment and Public Health for funding theproject Der Humuskorper bayerischer Boden im Klimawandel Auswirkungen und Potentiale.

    References

    AD-HOC AG Boden (2005) Bodenkundliche Kartieranleitung. Bundesanstalt fur Geowis-

    senschaften und Rohstoffe (Ed.). E. Schweizerbartsche Verlagsbuchhandlung, Stutt-

    gart.

    Amelung W, Zech W (1999) Minimisation of organic matter disruption during parti-

    cle-size fractionation of grassland epipedons. Geoderma, 92, 7385.

    Angers DA, Arrouays D, Saby NPA, Walter C (2011) Estimating and mapping the

    carbon saturation deficit of French agricultural topsoils. Soil Use and Management,

    27, 448452.

    Arrouays D, Saby N, Walter C, Lemercier B, Schvartz C (2006) Relationships between

    particle-size distribution and organic carbon in French arable topsoils. Soil Use and

    Management, 22, 4851.

    Baldock JA, Skjemstad JO (2000) Role of the soil matrix and minerals in protecting nat-

    ural organic materials against biological attack. Organic Geochemistry, 31, 697710.

    Balesdent J, Chenu C, Balabane M (2000) Relationship of soil organic matter dynamics

    to physical protection and tillage. Soil & Tillage Research, 53, 215230.

    Beven KJ, Kirkby MJ (1978) A physically based, variable contributing area model of

    basin hydrology. Hydrological Sciences Bulletin, 24, 4369.

    Carroll M, Milakovsky B, Finkral A, Evans A, Ashton MS (2012) Managing carbon

    sequestration and storage in temperate and boreal forests. In: Managing Forest

    Carbon in a Changing Climate (eds Ashton MS, Tyrrell ML, Spalding D, Gentry B),

    pp. 205226. Springer, New York.

    Carter MR, Angers DA, Gregorich EG, Bolinder MA (2003) Characterizing organic

    matter retention for surface soils in eastern Canada using density and particle size

    fractions. Canadian Journal of Soil Science, 83, 1123.

    Chan KY (2001) Soil particulate organic carbon under different land use and manage-

    ment. Soil Use and Management, 17, 217221.

    Chung HG, Grove JH, Six J (2008) Indications for soil carbon saturation in a temperate

    agroecosystem. Soil Science Society of America Journal, 72, 11321139.

    Ciais P, Schelhaas MJ, Zaehle S et al. (2008) Carbon accumulation in European forests.

    Nature Geoscience, 1, 425429.

    Cole CV, Duxbury J, Freney J et al. (1997) Global estimates of potential mitigation of

    greenhouse gas emissions by agriculture. Nutrient Cycling in Agroecosystems, 49,

    221228.

    Conant RT, Paustian K (2002) Potential soil carbon sequestration in overgrazed grass-

    land ecosystems. Global Biogeochemical Cycles, 16, 9.

    Conant RT, Six J, Paustian K (2003) Land use effects on soil carbon fractions in the

    southeastern United States. I. Management-intensive versus extensive grazing.

    Biology and Fertility of Soils, 38, 386392.

    Dumig A, Smittenberg R, Kogel-Knabner I (2011) Concurrent evolution of organic

    and mineral components during initial soil development after retreat of the

    Damma glacier, Switzerland. Geoderma, 163, 8394.

    Eusterhues K, Rumpel C, Kogel-Knabner I (2005) Stabilization of soil organic matter

    isolated via oxidative degradation. Organic Geochemistry, 36, 15671575.

    Feng WT, Plante AF, Six J (2013) Improving estimates of maximal organic carbon

    stabilization by fine soil particles. Biogeochemistry, 112, 8193.

    Freibauer A, Rounsevell MDA, Smith P, Verhagen J (2004) Carbon sequestration in

    the agricultural soils of Europe. Geoderma, 122, 123.

    Goh KM (2004) Carbon sequestration and stabilization in soils: implications for soil

    productivity and climate change. Soil Science and Plant Nutrition, 50, 467476.

    Goodale CL, Apps MJ, Birdsey RA et al. (2002) Forest carbon sinks in the Northern

    Hemisphere. Ecological Applications, 12, 891899.

    Hartge KH, Horn R (1989) Die physikalische Untersuchung von Boden. Enke Verlag,

    Stuttgart.

    Hassink J (1997) The capacity of soils to preserve organic C and N by their association

    with clay and silt particles. Plant and Soil, 191, 7787.

    Holland JM (2004) The environmental consequences of adopting conservation tillage

    in Europe: reviewing the evidence. Agriculture Ecosystems & Environment, 103,

    125.

    IUSS Working Group WRB (2006) World Reference Base for Soil Resources 2006. World

    Soil Resources Reports No. 103, FAO, Rome.

    Jandl R, Lindner M, Vesterdal L et al. (2007) How strongly can forest management

    influence soil carbon sequestration? Geoderma, 137, 253268.

    Johnson JMF, Franzluebbers AJ, Weyers SL, Reicosky DC (2007) Agricultural oppor-

    tunities to mitigate greenhouse gas emissions. Environmental Pollution, 150,

    107124.

    Joneck M, Hangen E, Martin W et al. (2006) Wissenschaftliche Grundlagen fur den

    Vollzug der Bodenschutzgesetze in Bayern (GRABEN) - ein Projekt stellt sich vor.

    Bodenschutz, 2, 3238.

    Kaiser K, Zech W (2000) Dissolved organic matter sorption by mineral constituents of

    subsoil clay fractions. Journal of Plant Nutrition and Soil Science, 163, 531535.

    Kaiser K, Eusterhues K, Rumpel C, Guggenberger G, Kogel-Knabner I (2002) Stabil-

    ization of organic matter by soil minerals - investigations of density and particle-

    size fractions from two acid forest soils. Journal of Plant Nutrition and Soil Science,

    165, 451459.

    Karjalainen T, Pussinen A, Liski J, Nabuurs GJ, Eggers T, Lapvetelainen T, Kaipainen

    T (2003) Scenario analysis of the impacts of forest management and climate change

    on the European forest sector carbon budget. Forest Policy and Economics, 5,

    141155.

    Kleber M, Mikutta R, Torn MS, Jahn R (2005) Poorly crystalline mineral phases

    protect organic matter in acid subsoil horizons. European Journal of Soil Science, 56,

    717725.

    Kogel-Knabner I, Guggenberger G, Kleber M et al. (2008) Organo-mineral associa-

    tions in temperate soils: integrating biology, mineralogy, and organic matter chem-

    istry. Journal of Plant Nutrition and Soil Science, 171, 6182.

    Lal R (2004) Agricultural activities and the global carbon cycle. Nutrient Cycling in

    Agroecosystems, 70, 103116.

    Lal R (2005) Forest soils and carbon sequestration. Forest Ecology and Management, 220,

    242258.

    Lal R (2007) Carbon management in agricultural soils. Mitigation and Adaption Strate-

    gies for Global Change, 12, 303322.

    Landres PB, Morgan P, Swanson FJ (1999) Overview of the use of natural variability

    concepts in managing ecological systems. Ecological Applications, 9, 11791188.

    Larocque GR, Bhatti JS, Boutin R, Chertov O (2008) Uncertainty analysis in carbon

    cycle models of forest ecosystems: research needs and development of a theoreti-

    cal framework to estimate error propagation. Ecological Modelling, 219, 400412.

    Liski J, Perruchoud D, Karjalainen T (2002) Increasing carbon stocks in the forest soils

    of western Europe. Forest Ecology and Management, 169, 159175.

    2013 John Wiley & Sons Ltd, Global Change Biology, 20, 653665

    664 M. WIESMEIER et al.

  • Lorenz K, Lal R (2010) Carbon Sequestration in Forest Ecosystems. Springer, New York.

    von Lutzow M, Kogel-Knabner I, Ekschmitt K, Matzner E, Guggenberger G, Marsch-

    ner B, Flessa H (2006) Stabilization of organic matter in temperate soils: mecha-

    nisms and their relevance under different soil conditions - a review. European

    Journal of Soil Science, 57, 426445.

    Luyssaert S, Ciais P, Piao SL et al. (2010) The European carbon balance. Part 3: forests.

    Global Change Biology, 16, 14291450.

    Mann LK (1986) Changes in soil carbon storage after cultivation. Soil Science, 142,

    279288.

    Oades JM (1988) The retention of organic matter in soils. Biogeochemistry, 5, 3570.

    Paustian K, Andren O, Janzen HH et al. (1997) Agricultural soils as a sink to mitigate

    CO2 emissions. Soil Use and Management, 13, 230244.

    Paustian K, Cole CV, Sauerbeck D, Sampson N (1998) CO2 mitigation by agriculture:

    an overview. Climatic Change, 40, 135162.

    Paustian K, Six J, Elliott ET, Hunt HW (2000) Management options for reducing CO2

    emissions from agricultural soils. Biogeochemistry, 48, 147163.

    Post WM, Kwon KC (2000) Soil carbon sequestration and land-use change: processes

    and potential. Global Change Biology, 6, 317327.

    Rumpel C, Kogel-Knabner I (2011) Deep soil organic matter-a key but poorly under-

    stood component of terrestrial C cycle. Plant and Soil, 338, 143158.

    Sauerbeck DR (2001) CO2 emissions and C sequestration by agriculture - perspectives

    and limitations. Nutrient Cycling in Agroecosystems, 60, 253266.

    Schoning I, Knicker H, Kogel-Knabner I (2005) Intimate association between O/N-

    alkyl carbon and iron oxides in clay fractions of forest soils. Organic Geochemistry,

    36, 13781390.

    Schubert A (2002) Bayerische Waldboden-Dauerbeobachtungsflachen - Bodenuntersuchun-

    gen. Wissenschaftszentrum Weihenstephan fur Ernahrung, Landnutzung und

    Umwelt der Technischen Universitat Munchen und Bayerische Landesanstalt fur

    Wald und Forstwirtschaft, Freising.

    Six J, Elliott ET, Paustian K (1999) Aggregate and soil organic matter dynamics under

    conventional and no-tillage systems. Soil Science Society of America Journal, 63,

    13501358.

    Six J, Elliott ET, Paustian K (2000) Soil macroaggregate turnover and microaggregate

    formation: a mechanism for C sequestration under no-tillage agriculture. Soil Biol-

    ogy & Biochemistry, 32, 20992103.

    Six J, Conant RT, Paul EA, Paustian K (2002) Stabilization mechanisms of soil organic

    matter: implications for C-saturation of soils. Plant and Soil, 241, 155176.

    Smith P (2004) Carbon sequestration in croplands: the potential in Europe and the

    global context. European Journal of Agronomy, 20, 229236.

    Smith P (2012) Agricultural greenhouse gas mitigation potential globally, in Europe

    and in the UK: what have we learnt in the last 20 years? Global Change Biology, 18,

    3543.

    Smith P, Martino D, Cai Z et al. (2008) Greenhouse gas mitigation in agriculture.

    Philosophical Transactions of the Royal Society B-Biological Sciences, 363, 789813.

    Sollins P, Homann P, Caldwell BA (1996) Stabilization and destabilization of soil

    organic matter: mechanisms and controls. Geoderma, 74, 65105.

    Sorensen R, Zinko U, Seibert J (2006) On the calculation of the topographic wetness

    index: evaluation of different methods based on field observations. Hydrology and

    Earth System Sciences, 10, 101112.

    Sparrow LA, Belbin KC, Doyle RB (2006) Organic carbon in the silt plus clay fraction

    of Tasmanian soils. Soil Use and Management, 22, 219220.

    Spielvogel S, Prietzel J, Kogel-Knabner I (2006) Soil organic matter changes in a

    spruce ecosystem 25 years after disturbance. Soil Science Society of America Journal,

    70, 21302145.

    Spielvogel S, Prietzel J, Kogel-Knabner I (2008) Soil organic matter stabilization in

    acidic forest soils is preferential and soil type-specific. European Journal of Soil

    Science, 59, 674692.

    Sporlein P, Dilling J, Joneck M (2004) Pilot study to test the equivalence or compara-

    bility of soil-particle-size analysis according to E DIN ISO 11277: 06.94 (pipette

    method) and by the use of the sedigraph. Journal of Plant Nutrition and Soil Science,

    167, 649656.

    Steffens M, Kolbl A, Kogel-Knabner I (2009) Alteration of soil organic matter pools

    and aggregation in semi-arid steppe topsoils as driven by organic matter input.

    European Journal of Soil Science, 60, 198212.

    Stewart CE, Paustian K, Conant RT, Plante AF, Six J (2007) Soil carbon saturation:

    concept, evidence and evaluation. Biogeochemistry, 86, 1931.

    Stewart CE, Paustian K, Conant RT, Plante AF, Six J (2008) Soil carbon saturation:

    evaluation and corroboration by long-term incubations. Soil Biology & Biochemistry,

    40, 17411750.

    Stockmann U, Adams MA, Crawford JW et al. (2013) The knowns, known unknowns

    and unknowns of sequestration of soil organic carbon. Agriculture, Ecosystems &

    Environment, 164, 8099.

    UGRdL (2012) Umweltokonomische Gesamtrechnung der Lander, Energieverbrauch und

    Treibhausgasemissionen - Analysen und Ergebnisse. Arbeitskreis Umweltokonomische

    Gesamtrechnung der Lander im Auftrag der Statistischen Amter der Lander.

    Available at: www.ugrdl.de (accessed 22 August 2013).

    Vesterdal L, Elberling B, Christiansen JR, Callesen I, Schmidt IK (2012) Soil respira-

    tion and rates of soil carbon turnover differ among six common European tree

    species. Forest Ecology and Management, 264, 185196.

    Vleeshouwers LM, Verhagen A (2002) Carbon emission and sequestration by

    agricultural land use: a model study for Europe. Global Change Biology, 8, 519

    530.

    West TO, Post WM (2002) Soil organic carbon sequestration rates by tillage and crop

    rotation: a global data analysis. Soil Science Society of America Journal, 66, 19301946.

    West TO, Six J (2007) Considering the influence of sequestration duration and carbon

    saturation on estimates of soil carbon capacity. Climatic Change, 80, 2541.

    Wiesmeier M, Sporlein P, Geuss U et al. (2012) Soil organic carbon stocks in southeast

    Germany (Bavaria) as affected by land use, soil type and sampling depth. Global

    Change Biology, 18, 22332245.

    Wiesmeier M, Hubner R, Barthold FK et al. (2013a) Amount, distribution and driving

    factors of soil organic carbon and nitrogen in cropland and grassland soils of

    southeast Germany (Bavaria). Agriculture Ecosystems & Environment, 176, 3952.

    Wiesmeier M, Prietzel J, Barthold FK et al. (2013b) Storage and drivers of organic car-

    bon in forest soils of southeast Germany (Bavaria) - Implications for carbon

    sequestration. Forest Ecology and Management, 295, 162172.

    Wilson J, Gallant J (2000) Terrain Analysis: Principles and Applications. John Wiley &

    Sons, Inc., New York.

    Wiseman CLS, Puttmann W (2005) Soil organic carbon and its sorptive preservation

    in central Germany. European Journal of Soil Science, 56, 6576.

    Zhao LP, Sun YJ, Zhang XP, Yang XM, Drury CF (2006) Soil organic carbon in clay

    and silt sized particles in Chinese mollisols: relationship to the predicted capacity.

    Geoderma, 132, 315323.

    2013 John Wiley & Sons Ltd, Global Change Biology, 20, 653665

    SOC SATURATION AND SEQUESTRATION POTENTIAL 665

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