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Cited by 391Soil Carbon and Nitrogen DynamicsBioenergy crop production and managementSoil erosion and sediment transport

Changes in soil organic carbon under biofuel crops

Open access
ANDERSON‐TEIXEIRA, KRISTINA J., DAVIS, SARAH C., MASTERS, MICHAEL D., DELUCIA, EVAN H.·2009·GCB Bioenergy
DOI 10.1111/j.1757-1707.2008.01001.x
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Abstract

Abstract One potentially significant impact of growing biofuel crops will be the sequestration or release of carbon (C) in soil. Soil organic carbon (SOC) represents an important C sink in the lifecycle C balances of biofuels and strongly influences soil quality. We assembled and analyzed published estimates of SOC change following conversion of natural or agricultural land to biofuel crops of corn with residue harvest, sugarcane, Miscanthus x giganteus , switchgrass, or restored prairie. We estimated SOC losses associated with land conversion and rates of change in SOC over time by regressing net change in SOC relative to a control against age since establishment year. Conversion of uncultivated land to biofuel agriculture resulted in significant SOC losses – an effect that was most pronounced when native land was converted to sugarcane agriculture. Corn residue harvest (at 25–100% removal) consistently resulted in SOC losses averaging 3–8 Mg ha −1 in the top 30 cm, whereas SOC accumulated under all four perennial grasses, with SOC accumulation rates averaging <1 Mg ha −1 yr −1 in the top 30 cm. More intensive harvests led to decreased C gains or increased C losses – an effect that was particularly clear for residue harvest in corn. Direct or indirect conversion of previously uncultivated land for biofuel agriculture will result in SOC losses that counteract the benefits of fossil fuel displacement. Additionally, SOC losses under corn residue harvest imply that its potential to offset C emissions may be overestimated, whereas SOC sequestration under perennial grasses represents an additional benefit that has rarely been accounted for in life cycle analyses of biofuels.

AI snapshot

Written from the paper’s full text.

TL;DR

This synthesis of published soil-carbon measurements finds that clearing uncultivated land for biofuel crops causes soil organic carbon (SOC) losses, corn residue harvest consistently depletes SOC, and perennial grasses tend to build SOC. The authors argue these SOC changes should be included in biofuel life-cycle assessments because they can offset or add to the benefits of displacing fossil fuels.

Key findings

  • Across 46 studies and 164 site-treatment combinations, converting native land to biofuel agriculture produced significant SOC losses, with the largest effect when native ecosystems became sugarcane. Corn residue removal at 25–100% consistently lost SOC, averaging 3–8 Mg C ha⁻¹ in the top 30 cm, while all four perennial grass systems accumulated SOC at average rates below 1 Mg C ha⁻¹ yr⁻¹ in the top 30 cm.
  • For corn, SOC loss increased with residue removal: about 0.2% per 1% increase in removal, or 0.06–0.09 Mg C ha⁻¹ per 1% increase. A 10-year projection gave roughly 3 Mg C ha⁻¹ lost per 30 cm at 25% removal and about 8 Mg C ha⁻¹ at 100% removal.
  • Sugarcane conversion from native land showed an initial loss of about 22% or 20 Mg C ha⁻¹ to a median depth of 15 cm, with model projections up to about 50% near the surface or 34 Mg C ha⁻¹ in the top 30 cm; free-intercept accumulation was 0.29 Mg C ha⁻¹ yr⁻¹ and ANOVA-based accumulation was 0.51 Mg C ha⁻¹ yr⁻¹, with payback within a century but based on only five sites.
  • Miscanthus conversion from grassland averaged an 11% or 5.8 Mg C ha⁻¹ loss that was not statistically significant, and free-intercept accumulation averaged 1.0 Mg C ha⁻¹ yr⁻¹ versus 0.14 Mg C ha⁻¹ yr⁻¹ from forced-intercept calculations. Switchgrass percentage SOC increased by 1.8% yr⁻¹ and area-based SOC by about 0.4 Mg C ha⁻¹ yr⁻¹ in ANOVA models or 0.68 Mg C ha⁻¹ yr⁻¹ in forced-intercept models; mixed native sites had intercepts about 68% or 16 Mg C ha⁻¹ above controls and increased by about 1% yr⁻¹ or 0.1 Mg C ha⁻¹ yr⁻¹.

Methods

  • The authors searched ISI Web of Science in spring 2008 for studies of SOC change after crop establishment, requiring at least two known field ages including a control, total SOC measured after root removal by dry combustion or dichromate oxidation, and SOC reported by depth or area. They retained 46 studies with 164 site-treatment combinations.
  • They estimated SOC accumulation rates and land-conversion effects per site using forced-intercept and free-intercept linear regressions, comparing free intercepts with controls via one-sided t-tests. They also combined sites in ANOVA models (type III SS) for percentage SOC change and net SOC change as functions of age, log depth, biomass removal, and clay, with reduced models for some crops; influential points were removed using Cook’s D.
  • Bulk density was used to convert between concentration and area units, calculated with an Adams–Stewart adaptation when missing; clay content was estimated from texture descriptions when not reported.

Limitations

  • Stated: the analysis assumes controls are at steady state, so results describe change relative to continued control land use rather than absolute baseline behavior. SOC is spatially variable and hard to match between treatments and controls, and bulk-density shifts can bias area-based SOC changes, likely underestimating both losses and gains; for sugarcane this may mean underestimating both conversion loss and later accumulation.
  • Stated: the data come from studies with differing designs and substantial variation in sampling, prior land use, age, depth, management, soil type, and climate, so coefficients should be interpreted cautiously and direct numerical comparisons of accumulation rates among crops are inappropriate; side-by-side trials are needed. Some crops have limited data, such as Miscanthus, or poor representation of certain conditions, such as old corn residue sites and harvested mixed native systems.
  • Evident from the text: several key estimates rely on very small samples, including five sites for sugarcane and Miscanthus free-intercept calculations and seven for mixed native free-intercept calculations; switchgrass land-conversion effects could not be reliably assessed because only three sites had multiple ages and none exceeded 3 years.

Model-written summary. Check it against the paper before relying on it.

Integrity signals

Registry

Crossref · 10.1111/j.1757-1707.2008.01001.x

Cites

134 of 134 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

5 of 74 cited sources checked · 4 supported · 1 flagged · accuracy not yet measured

  • Findingcitation

    Cultivation of temperate-zone perennial grasses, Miscanthus, switchgrass, or native mixes, increased SOC by an average of about 0.1-1 Mg/ha/yr in the top 30 cm.

    “Cultivation of temperate-zone perennial grasses -Miscanthus, switchgrass, or native mixes -increased SOC by an average of $ 0.1-1 Mg ha À1 yr À1 in the top 30 cm (Figs 234; see also e.g., Potter et al., 1999;Ma et al., 2000;Kahle et al., 2001;Lemus & Lal, 2005;Liebig et al., 2008).”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Potter et al., 1999 source
    • cites Ma et al., 2000

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Liebig et al., 2008 source
  • Interpretationcitation

    A switch from conventional tillage to no-till concurrent with initiation of residue harvest may offset the negative effects of residue harvest in corn.

    “In the case of corn, we note that a switch from conventional tillage to no-till concurrent with initiation of residue harvest may offset the negative effects of residue harvest (Clapp et al., 2000;Adler et al., 2007).”
    Quote in the paperNot a substantial claim1 of 2 sources checked
    • cites Clapp et al., 2000 source
    • cites Adler et al., 2007 source
  • Findingown data

    The sugarcane land conversion loss was roughly 22% or 20 Mg C/ha to a median depth of 15 cm based on comparison of controls and intercepts.

    “The land conversion loss was roughly 22% or 20 Mg C ha À1 (to a median depth of 15 cm) based on comparison of controls and intercepts (n 5 5, P 5 0.04), but these estimates varied widely depending on ages and depths measured.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The free-intercept model's intercept difference from the control estimates the land conversion effect.
  • Findingown data

    Conversion of grassland to Miscanthus generally resulted in modest C losses followed by SOC accumulation.

    “Conversion of grassland to Miscanthus generally resulted in modest C losses followed by SOC accumulation.”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: The free-intercept model's intercept difference from the control estimates the land conversion effect.
  • Findingown data

    The free-intercept model indicated that SOC began to rebuild following an initial loss under sugarcane, with dSOCa/dt of 0.29 Mg C/ha/yr.

    “However, the free-intercept model indicated that SOC began to rebuild following an initial loss (dSOC a /dt 5 0.29 Mg C ha À1 yr À1 , SE 5 0.31, n 5 5; Fig. 4a).”
    Quote in the paperSubstantial claim
  • May combine two claims. 40
  • Classified as probably not a substantial claim. 9

  • May combine two claims.

    Interpretationown data

    SOC losses of the magnitude observed here have not been included in life cycle analyses of biofuel production from corn residue, which implies that the sustainability and net benefits of biofuel production from residue have been overestimated.

    “SOC losses of the magnitude observed here have not been included in life cycle analyses of biofuel production from corn residue (Sheehan et al., 2003;Powers, 2005;Spatari et al., 2005;Adler et al., 2007), which implies that the sustainability and net benefits of biofuel production from residue have been overestimated.”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Sheehan et al., 2003 source

      Split into 2 atoms — 1 confirmed, 0 partially supported, 1 disputed, 0 misattributed, 0 unverifiable. Expand the claim to see per-atom verdicts.

      Checked by a reasoning model — may be wrong.

      Experimental — accuracy not yet measured
    • cites Powers, 2005 source
    • cites Spatari et al., 2005 source

  • May combine two claims.

    Premisecitation

    SOC sequestration is an important component in the life cycle of biofuel production and may be key in determining the greenhouse gas reduction potential of biofuels relative to fossil fuels.

    “SOC sequestration is an important component in the life cycle of biofuel production (Ney & Schnoor, 2002;Adler et al., 2007) and may be key in determining the greenhouse gas (GHG) reduction potential of biofuels relative to fossil fuels.”
    Quote in the paperSubstantial claim1 of 2 sources checked
    • cites Ney & Schnoor, 2002

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Adler et al., 2007 source

  • May combine two claims.

    Premisecitation

    Changes in SOC will significantly affect efforts to mitigate GHG emissions and impact a host of other ecosystem services.

    “Changes in SOC will significantly affect efforts to mitigate GHG emissions (Ney & Schnoor, 2002;Adler et al., 2007) and impact a host of other ecosystem services (Lal, 2004).”
    Quote in the paperSubstantial claim1 of 3 sources checked
    • cites Ney & Schnoor, 2002

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Adler et al., 2007 source
    • cites Lal, 2004 source

  • May combine two claims.

    Findingown data

    The land conversion effect for mixed native sites was positive; intercepts were about 68% or 16 Mg C/ha greater than controls; the ratio of intercept to control was significantly greater than 1.

    “The land conversion effect was positive (Figs 3 and 4d); intercepts were $ 68% or 16 Mg C ha À1 greater than the controls; and the ratios of the intercept to the control was significantly 41 (one-sample t-test; P 5 0.02).”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: The free-intercept model's intercept difference from the control estimates the land conversion effect.

  • May combine two claims.

    Findingown data

    More intensive harvests led to decreased C gains or increased C losses.

    “More intensive harvests led to decreased C gains or increased C losses -an effect that was particularly clear for residue harvest in corn.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    Switchgrass studied in the literature typically was planted on cropland, fallow land, or grassland.

    “Switchgrass studied in the literature typically was planted on cropland, fallow land, or grassland (Table 1).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The average Miscanthus land conversion loss was approximately 11% or 5.8 Mg C/ha.

    “The average land conversion loss was approximately 11% or 5.8 Mg C ha À1 (n 5 5; Fig. 4b); however, the ratio of the intercept to the control was not significantly o1 (P 5 0.16), indicating that this loss was not significant.”
    Quote in the paperNot a substantial claim
    • The authors state this as an assumption: The free-intercept model's intercept difference from the control estimates the land conversion effect.

  • May combine two claims.

    Findingown data

    The forced-intercept model gave negative rates of change in SOCa for sugarcane, -0.67 Mg C/ha/yr, indicating a net loss of SOC for the majority of sites.

    “As a result of this initial loss, the forced-intercept model gave negative rates of change in SOC a (À0.67 Mg C ha À1 yr À1 , SE 5 0.36, n 5 18; Fig. 4a), indicating a net loss of SOC for the majority of sites (median age 5 35; Table 1).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    When biomass was harvested under switchgrass, SOC accumulation tended to be less rapid, partially offset by higher intercepts.

    “When biomass was harvested, SOC accumulation tended to be less rapid (SOC c : P 5 0.05, SOC a : P 5 0.66; Tables B1 and B2), but this was partially offset by higher intercepts (SOC c : P 5 0.07; SOC a : P 5 0.72; Tables B1 and B2).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The statistical model predicted that 10 years of maize biomass removal resulted in losses of about 3 Mg C/ha per 30 cm at 25% residue removal and about 8 Mg C/ha per 30 cm at 100% residue removal.

    “Overall, our statistical model (Table B2) predicted that 10 years of maize biomass removal resulted in losses of $ 3 Mg C ha À1 per 30 cm at 25% residue removal and $ 8 Mg C ha À1 per 30 cm at 100% residue removal (Fig. 3).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    ANOVA models indicated sugarcane SOC accumulation rates of about 0.33% yr-1 or 0.51 Mg C/ha/yr.

    “Likewise, the ANOVA models indicated SOC accumulation rates of about 0.33% yr À1 (SOC c reduced model: P 5 0.10; Fig. 2b) or 0.51 Mg C ha À1 yr À1 (SOC a reduced model: P 5 0.006; Fig. 3).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    SOC tended to accumulate over time under switchgrass; percentage change in SOCc increased with age by 1.8% yr-1.

    “SOC tended to accumulate over time (Figs 234); percentage change in SOC c increased with age by 1.8% yr À1 (Fig. 2d; P 0.04 for reduced and full models; Table B1) and SOC a increased with age at a rate of $ 0.4 Mg ha À1 yr À1 according to the ANOVA models (Fig. 3; P40.3 for reduced and full models; Table B2), or 0.68 Mg ha À1 yr À1 according to the forced-intercept model (SE 5 0.30, n 5 87; Fig. 2”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Tillage releases SOC and was probably largely responsible for the observed land conversion losses.

    “Tillage releases SOC and was probably largely responsible for the observed land conversion losses (Fig. 4).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    Harvesting biomass appears to reduce SOC or to slow its rate of accumulation.

    “Harvesting biomass appears to reduce SOC or to slow its rate of accumulation.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    In the full ANOVA model for corn, the interaction between age and residue removal was not significantly associated with percent change in SOC (coefficient 0.006, SE 0.008, p=0.44).

    “Age  residue removal 0.006 (0.008) 1 39.1 39.1 0.6 0.44”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    In the ANOVA models for corn, age (years) was not significantly associated with percent change in SOC (full model coefficient 0.36, SE 0.84, p=0.67; reduced model coefficient 0.35, SE 0.41, p=0.40).

    “Age (years) 0.36 (0.84) 1 11.9 11.9 0.2 0.67 0.35 (0.41) 1 54.0 54.0 0.7 0.40”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    In the ANOVA models for corn, log(depth) (cm) had a positive effect on percent change in SOC (full model coefficient 7.86, SE 3.24, p=0.02; reduced model coefficient 6.25, SE 1.48, p<0.0001).

    “Log(depth) (cm) 7.86 (3.24) 1 384 384 5.9 0.02 6.25 (1.48) 1 1367.21367.2 17.9 o0.0001”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data

    In the full ANOVA model for corn, the interaction between age and log(depth) was not significantly associated with percent change in SOC (coefficient -0.12, SE 0.39, p=0.44).

    “Age  log(depth) À0.12 (0.39) 1 6.5 6.5 0.1 0.44”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning

    Whereas soil C is depleted under corn residue harvest, it accumulates under cultivation of perennial grasses.

    “Whereas soil C is depleted under corn residue harvest, it accumulates under cultivation of perennial grasses.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisereasoning

    The forced-intercept model assumes a linear change in SOC through time, and therefore will underestimate rates of SOC change if there is a land conversion loss.

    “This forced-intercept model assumes a linear change in SOC through time, and therefore will underestimate rates of SOC change if there is a land conversion loss (Fig. 1).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Conversion of native ecosystems to crops causes substantial losses of SOC averaging about 30%, most rapid immediately following land conversion, probably stabilizing within the first several decades of cultivation.

    “Conversion of native ecosystems to crops causes substantial losses of SOC (averaging about 30%), which is most rapid immediately following land conversion (Davidson & Ackerman, 1993;Guo & Gifford, 2002;Murty et al., 2002;West et al., 2004;Zinn et al., 2005;De Deyn et al., 2008;David et al., in press), probably stabilizing within the first several decades of cultivation (David et al., in press).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Davidson & Ackerman, 1993 source
    • cites Guo & Gifford, 2002 source
    • cites David et al., in press

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Because grasslands tend to have high SOC, conversion of native ecosystems to pasture generally does not release SOC, and sometimes results in modest SOC sequestration.

    “Because grasslands tend to have high SOC, conversion of native ecosystems to pasture generally does not release SOC, and sometimes results in modest SOC sequestration (Fisher et al., 1994;Guo & Gifford, 2002;Murty et al., 2002;Osher et al., 2003;Zinn et al., 2005).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Fisher et al., 1994 source
    • cites Guo & Gifford, 2002 source
    • cites Zinn et al., 2005 source

  • May combine two claims.

    Study design and conductown data

    Land conversion effect for switchgrass could not be reliably assessed, as only three sites had data for more than one age, and none exceeded 3 years in age.

    “Land conversion effect could not be reliably assessed, as only three sites had data for more than one age, and none of these exceeded 3 years in age (Table 1).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation

    The SOC loss from clearing uncultivated land may be attributed to effects of tillage, which stimulates release of C from soil, or to a deficiency of organic inputs relative to decomposition early in crop establishment.

    “This may be attributed to the effects of tillage, which stimulates a release of C from soil (e.g., Reicosky et al., 1997) or to a deficiency of organic inputs relative to decomposition early in crop establishment (Paul et al., 2002).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Reicosky et al., 1997 source
    • cites Paul et al., 2002 source

  • May combine two claims.

    Premisecitation

    The biofuel crops considered here match the pattern of lower root allocation in annual crops than in grasslands; observed root:shoot ratios are ≤0.3 for fertilized corn, ≤0.15 for sugarcane in nonfield conditions, ≤1 for Miscanthus, 1.8-6.1 for switchgrass, and 2-8 for North American prairies.

    “The biofuel crops considered here match this pattern; observed root : shoot ratios are $0.3 for fertilized corn (Bonifas et al., 2005), $0.15 for sugarcane in nonfield conditions (Ebrahim et al., 1998;Smith et al., 2005), $1 for Miscanthus (Neukirchen et al., 1999), 1.8-6.1 for switchgrass (Ma et al., 2001), and 2-8 for North American prairies (Wilson, 1993;Ojima et al., 1994).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Bonifas et al., 2005 source
    • cites Ebrahim et al., 1998 source
    • cites Smith et al., 2005 source

  • May combine two claims.

    Interpretationreasoning

    For sugarcane, the bulk density bias implies underestimates of both the land conversion loss and the rate of SOC accumulation.

    “For sugarcane, this would imply underestimates of both the land conversion loss and the rate of SOC a accumulation.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    The rate of soil organic matter mineralization generally responds positively to increased soil moisture but negatively to decreased temperature.

    “As the rate of soil organic matter mineralization generally responds positively to increased soil moisture but negatively to decreased temperature (Leiro ´s et al., 1999), it is not clear how differences in cover among crops affect SOC losses.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Leiro ´s et al., 1999

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Change in SOC is artificially high (tending toward gains) where bulk density has increased and artificially low (tending toward losses) where it has decreased.

    “As a result, change in SOC a is artificially high (tending toward gains) in situations where bulk density has increased and artificially low (tending toward losses) in situations where it has decreased (Ellert et al., 2000).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Ellert et al., 2000

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • Probably not a substantial claim: may not pass S2 (checkable). May combine two claims.

    Interpretationreasoning

    Direct numerical comparisons of SOC accumulation rates among crop types would be inappropriate; rather, side-by-side comparisons of perennial grasses will be necessary to rank their SOC accumulation rates.

    “As a result, estimated coefficients should be interpreted with caution; for example, direct numerical comparisons of SOC accumulation rates among crop types would be inappropriate; rather, side-by-side comparisons of perennial grasses will be necessary to rank their SOC accumulation rates.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductown data

    Our data comes from multiple studies with differing research designs, such that there is substantial within- and between-crop variation in factors such as number of samples, previous land uses, ages and depths sampled, management practices, soil types, and climate.

    “It is also noteworthy that our data comes from multiple studies with differing research designs, such that there is substantial within-and between-crop variation in factors such as number of samples, previous land uses, ages and depths sampled, management practices, soil types, and climate (Tables 1, A1).”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Both production and decomposition increase with precipitation, but the relative advantage appears to switch from decomposition at low precipitation to production at high precipitation.

    “Both production and decomposition increase with precipitation, but the relative advantage appears to switch from decomposition at low precipitation to production at high precipitation (Austin, 2002).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Austin, 2002 source

  • May combine two claims.

    Study design and conductcitation

    SOC is spatially variable, making it difficult to match treatments with controls and to detect change in SOC, which increases variability within our data set.

    “SOC is spatially variable, making it difficult to match treatments with controls (Ellert et al., 2000) and to detect change in SOC (Garten & Wullschleger, 1999) -a problem that increases the variability within our data set.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Ellert et al., 2000

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

    • cites Garten & Wullschleger, 1999 source

  • May combine two claims.

    Premisecitation

    For sugarcane fields converted from native forest in Hawaii, sites with rainfalls of 2500 mm yr−1 and 4000 mm yr−1 had lost similar amounts of forest C, but sites receiving more rainfall had accumulated cane-derived C at a higher rate.

    “For sugarcane fields converted from native forest in Hawaii, sites with rainfalls of 2500 mm yr À1 and 4000 mm yr À1 had lost similar amounts of forest C, but sites receiving more rainfall had accumulated cane-derived C at a higher rate (Osher et al., 2003).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Osher et al., 2003 source

  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Interpretationreasoning

    The proportionally greater C accumulation at shallow depths in prairie may be attributable to the fact that prairie sites were not harvested.

    “Harvesting may also affect the depth distribution of new C inputs; the proportionally greater C accumulation at shallow depths in prairie (Fig. 2e) -which contrasts with the depth-independence of percentage change in C concentration of Miscanthus and switchgrass (Fig. 2c and d)may be attributable to the fact that prairie sites were not harvested (Table 1).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Decomposition is influenced by litter quality; high lignin content of litter extends the residence time of C in the soil.

    “Additionally, decomposition is influenced by litter quality; high lignin content of litter extends the residence time of C in the soil (McClaugherty et al., 1985).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites McClaugherty et al., 1985 source

  • May combine two claims.

    Interpretationreasoning

    Temperate perennial grasses introduce far more C to the soil than corn, potentially explaining the difference between corn and these grasses.

    “Thus, the temperate perennial grasses introduce far more C to the soil than corn, potentially explaining the difference between corn and these grasses.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Soil type affects both the input of C to the soil by affecting plant productivity and the decomposition of organic matter.

    “Soil type affects both the input of C to the soil by affecting plant productivity (Epstein et al., 1997) and the decomposition of organic matter (Sorensen, 1981;Paul, 1984;Jobba ´gy & Jackson, 2000).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Epstein et al., 1997 source
    • cites Sorensen, 1981 source
    • cites Paul, 1984

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Development of corn to maximize energy allocation to grain may reduce the complexity of tissues that eventually become litter, making its tissues readily degradable.

    “Development of corn to maximize energy allocation to grain may reduce the complexity of tissues that eventually become litter (Gifford et al., 1984), making its tissues readily degradable.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Gifford et al., 1984 source

  • Probably not a substantial claim: may not pass S3 (load-bearing). May combine two claims.

    Premisecitation

    Both productivity and decomposition increase with mean annual temperature such that SOC turnover should be fastest in warm climates.

    “Both productivity and decomposition increase with mean annual temperature such that SOC turnover should be fastest in warm climates (Schimel et al., 1994) and any proportional difference between the input of new organic material and decomposition of the old will tend to translate into faster rates of SOC loss or gain (Post & Kwon, 2000;Paul et al., 2002).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Schimel et al., 1994 source

  • May combine two claims.

    Premisecitation

    Allocation of C to root biomass is dramatically lower in traditional annual crops than in temperate grasslands, with globally averaged root:shoot ratios of 0.1 and 3.7, respectively.

    “Allocation of C to root biomass is dramatically lower in traditional annual crops than in temperate grasslands, with globally averaged root : shoot ratios of 0.1 and 3.7, respectively (Jackson et al., 1996).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Jackson et al., 1996 source

  • May combine two claims.

    Premisecitation

    In switchgrass crops planted across a temperature gradient in North America, SOC turnover rate, the proportion of switchgrass-derived SOC, and net change in SOC all increased with temperature.

    “In switchgrass crops planted across a temperature gradient in North America, SOC turnover rate, the proportion of switchgrassderived SOC, and net change in SOC all increased with temperature (Garten & Wullschleger, 2000).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Garten & Wullschleger, 2000 source

  • May combine two claims.

    Interpretationreasoning

    The effect of harvest on switchgrass SOC accumulation was partially offset by higher intercepts for harvested fields, which is more likely a statistical artifact than a biological reality.

    “For switchgrass, harvested fields tended to accumulate SOC less rapidly than fields that have not been harvested, but this effect was partially offset by higher intercepts for harvested fields (Tables B1 and 2), which is more likely a statistical artifact than a biological reality.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    The protective cover of canopies or litter layers affects the microclimate, reducing evaporation rates and dampening temperature fluctuations.

    “The protective cover of canopies or litter layers affects the microclimate, reducing evaporation rates and dampening temperature fluctuations (Wilhelm et al., 2004).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Wilhelm et al., 2004

      Couldn’t be matched to a paper in Crossref, so it can’t be checked.

  • May combine two claims.

    Premisecitation

    Changes in SOC are not typically included in sugarcane life cycle analyses, but could have a substantial impact on their outcomes.

    “Changes in SOC are not typically included in sugarcane life cycle analyses (Mohee & Beeharry, 1999;Beeharry, 2001;Botha & von Blottnitz, 2006), but could have a substantial impact on their outcomes.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Mohee & Beeharry, 1999 source
    • cites Beeharry, 2001 source
    • cites Botha & von Blottnitz, 2006 source

  • May combine two claims.

    Interpretationcitation

    Advancements in harvest efficiency, reduced allocation to roots through genetic modifications or changes in cultivation practices, or genetic modifications that yield more decomposable plants could reduce or possibly reverse SOC sequestration.

    “Advancements in harvest efficiency, reduced allocation to roots through genetic modifications or changes in cultivation practices (e.g., fertilization), or genetic modifications that yield more decomposable plants (Ragauskas et al., 2006) could reduce -or possibly even reverse -SOC sequestration.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Ragauskas et al., 2006 source

  • Probably not a substantial claim: may not pass S4 (based).

    Interpretationreasoning

    In such cases, the soil C sequestration benefits would augment the GHG reduction associated with fossil fuel displacement.

    “In such cases, the soil C sequestration benefits would augment the GHG reduction associated with fossil fuel displacement.”
    Quote in the paperNot a substantial claim
46 of 46

  • The paper relies on this without support.

    Many studies have quantified changes in SOC under potential biofuel crops, but results are variable and have yet to be synthesized into a coherent picture.

    “While many studies have quantified changes in SOC under potential biofuel crops, results are variable and have yet to be synthesized into a coherent picture.”

  • The authors state this as an assumption.

    The free-intercept model's intercept difference from the control estimates the land conversion effect.

    “This model uses a regression of net change in SOC relative to the control as a function of time to calculate a SOC accumulation rate and an intercept, which differs from the control when there is a land conversion effect.”

  • The authors state this as an assumption.

    Controls are at steady-state with respect to SOC.

    “First, our analysis assumes that controls are at steady-state with respect to SOC (Fig. 1), which may not be true of some controls (e.g., fallows, young grasslands).”
3 of 3

Claims other papers make about this one

Each is checked against this paper’s own text: does it say what the citing paper says it does?

  • Advanced lignocellulosic bioenergy crops like miscanthus have the potential to cut GHG emissions more effectively than corn.

    “According to studies conducted over the last 15 years, advanced lignocellulosic bioenergy crops like miscanthus have the potential to cut GHG emissions more effectively than corn (Anderson- Teixeira et al., 2009; Davis et al., 2012; Hudiburg etal.,2015; Von Hellfeld etal.,2022).”

    From Decadal change in soil carbon and nitrogen with a <i>Miscanthus</i> × <i>giganteus</i> crop on abandoned agricultural land in southeast Ohio (2024) · cites this paper as Anderson- Teixeira et al., 2009

    The Discussion reports that Miscanthus and other perennial grasses accumulate soil organic carbon, while corn with residue harvest loses it; the paper says this gives perennial grasses an additional carbon-offset benefit. It does not establish that Miscanthus cuts overall GHG emissions more effectively than corn generally: its comparison concerns the soil-carbon component and corn residue harvest specifically. (LLM, conf=0.84)

    Experimental — accuracy not yet measured

  • When grasslands are cleared and tilled for the purpose of cultivating miscanthus, it results in C losses until new C accumulation reaches a level sufficient to restore the initial loss that occurred during crop planting.

    “When grasslands are cleared and tilled for the purpose of cultivating miscanthus, it results in C losses until new C accumulation reaches a level that is sufficient to restore the initial loss that occurred during crop planting (Anderson- Teixeira etal.,2009; Jones etal.,2016).”

    From Decadal change in soil carbon and nitrogen with a <i>Miscanthus</i> × <i>giganteus</i> crop on abandoned agricultural land in southeast Ohio (2024) · cites this paper as Anderson-Teixeira et al., 2009

    The discussion (p. 80) says clearing and tilling grassland for biofuel crops causes an initial soil-carbon loss that later accumulation must restore. But the Miscanthus-specific Results describe the apparent conversion loss as modest and not statistically significant, so the claim states that outcome more certainly than the source does. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

  • Conversion from annual cropland to a perennial crop such as miscanthus is expected to increase C sequestration due to greater belowground allocation of C compared to annual crops.

    “Conversion from annual cropland to a perennial crop such as miscanthus is expected to increase C sequestration due to greater belowground allocation of C compared to annual crops (Anderson- Teixeira et al., 2009; Davis etal.,2010).”

    From Decadal change in soil carbon and nitrogen with a <i>Miscanthus</i> × <i>giganteus</i> crop on abandoned agricultural land in southeast Ohio (2024) · cites this paper as Anderson-Teixeira et al., 2009

    The Discussion (p. 80) says Miscanthus has greater root allocation than corn and that this may explain why perennial grasses gain soil organic carbon while corn loses it. That supports the proposed mechanism, but the paper’s Miscanthus conversion results concern grassland, not annual cropland; it does not directly assess the specified conversion. (LLM, conf=0.84)

    Experimental — accuracy not yet measured

  • The net change of soil surface 30 cm soil organic carbon in 15 years is predicted to be 6.49 Mg ha−1.

    “The net change of soil surface 30 cm soil organic carbon in 15 years is predicted to be 6.49 Mg ha−1, significantly higher than that of other crops.”

    From Effects of Biofuel Crop Switchgrass (Panicum virgatum) Cultivation on Soil Carbon Sequestration and Greenhouse Gas Emissions: A Review (2022) · cites this paper as [19]

    Figure 3 (p. 81) presents projected net SOC changes in the top 30 cm for crops of various ages, including 15 years. Our copy does not give a 15-year prediction of 6.49 Mg ha−1. It also cautions that direct numerical comparisons among crop types are inappropriate, so it does not support the claim that this value is significantly higher than for other crops. (LLM, conf=0.86)

    Experimental — accuracy not yet measured

  • In general, annual cropland conversion to perennial crops results in increased SOC stocks but SOC decreased if perennial crops or grasslands are converted to annual crops.

    “In general, annual cropland conversion to perennial crops results in increased SOC stocks but SOC decreased if perennial crops or grasslands are converted to annual crops (Anderson-Teixeira et al., 2009;Poeplau et al., 2011).”

    From Land‐use change to bioenergy production in <scp>E</scp> urope: implications for the greenhouse gas balance and soil carbon (2012) · cites this paper as Anderson-Teixeira et al., 2009

    The Introduction (page not specified) says SOC accumulates when cultivated land becomes grassland, while conversion of native ecosystems to crops causes substantial SOC losses. The Discussion (page not specified) also reports SOC gains under perennial grasses and initial losses when native grassland or forest is converted to sugarcane. The paper does not establish the claimed general decrease specifically for conversion of perennial crops or grasslands to annual crops; its grassland-conversion example is sugarcane, a perennial crop. (LLM, conf=0.84)

    Experimental — accuracy not yet measured

Self-check

Percentages, sums and reported differences re-computed from the paper’s own numbers.

Each contradiction between two passages listed here was confirmed by an independent check.

  • Mixed-native clay effect has the opposite sign

    Major

    The results describe a positive clay effect on area-based SOC change, but the cited full model gives clay a negative coefficient.

  • Mixed-native model includes a harvest category despite a no-harvest claim

    Major

    The paper says none of the mixed-native fields were harvested, yet its full model reports an estimated coefficient for annual harvest in that crop group.

  • Mixed-native depth result cites an unsupported reduced-model significance

    Major

    The results give P = 0.002 for sampling depth in the reduced area-based model. Table B2 instead gives P = 0.23 for that model; its full-model value is P = 0.02.

3 of 3

Cites

Flagged first, then by citations

Research works printed but not linked: 2

  1. Renewable Fuels Agency, 2008, The Gallagher Review of the Indirect Effects of Biofuels Production
  2. 10.1021/es048293 · DOI

Cited by

Sorted by citations

Related

Authors
ANDERSON‐TEIXEIRA, K. J., DAVIS, S. C., MASTERS, M. D., & DELUCIA, E. H.
Affiliations
University of Illinois Urbana-Champaign (US)
ORCID
Venue
GCB Bioenergy
Publisher
Wiley
Published
2009-02
Volume
1
Issue
1
Pages
75-96
ISSN
  • 1757-1693 (ISSN-L)
  • 1757-1707
DOI
10.1111/j.1757-1707.2008.01001.x
OpenAlex
W2000786281
Semantic Scholar
b7122b4a1607d7e200d13acb4c21f0e0b2d26e24
Cited by
391
References
131
Citations by year
2026: 6 · 2025: 8 · 2024: 10 · 2023: 15 · 2022: 10 · 2021: 24 · 2020: 24 · 2019: 22 · 2018: 25 · 2017: 39 · 2016: 28 · 2015: 34 · 2014: 34 · 2013: 39 · 2012: 37
FWCI
40.77
Type
journal article
Language
en
Open access
Licence
onlinelibrary.wiley.com/termsAndConditions#vor (vor, 24 d)
Locations
GCB Bioenergy (publishedVersion)
Funders
  • Energy Biosciences Institute
  • University of Illinois at Urbana-Champaign
Topics
  • Life Sciences › Agricultural and Biological Sciences › Soil Science › Soil Carbon and Nitrogen Dynamics
  • Life Sciences › Agricultural and Biological Sciences › Agronomy and Crop Science › Bioenergy crop production and management
  • Life Sciences › Agricultural and Biological Sciences › Soil Science › Soil erosion and sediment transport
Keywords
soil organic carbon, energy crops, land conversion, carbon sequestration, sugarcane, Miscanthus × giganteus, switchgrass, restored prairie, perennial grasses, carbon cycle, life cycle assessment

About these checks

Registry, retraction, Cites and statistics results are computed, not judged, with one exception: a printed reference that no index lists is read once by a model before it counts as a citation error. Claims are extracted by a model and kept only when their quote appears verbatim in the text; each cited source is then checked, with a model’s help, for whether it says what the claim relies on. Those verdicts can be wrong — read the claim’s quote and the cited source before relying on one.

Claims read by deepseek-v4.1-flash under definition version 3 (extract-v3) on 2026-10-11.

Classified by jev-1.13-20260917 (gold-guideline-v0.2) on 2026-10-11.

Cited sources are checked by gpt-6-sol.

Statistics and arithmetic are recomputed, not judged.

Confidence bands are shown only for fields calibrated on our annotated test set. None is calibrated yet, so no band is shown.

What counts as a claim ›How we measure confidence ›How we check this ›

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