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Cited by 40Bioenergy crop production and managementSoil Carbon and Nitrogen DynamicsLand Use and Ecosystem Services

Land‐use change to bioenergy: grassland to short rotation coppice willow has an improved carbon balance

Open access
Harris, Zoe M., Alberti, Giorgio, Viger, Maud, Jenkins, Joe R., Rowe, Rebecca, McNamara, Niall P., Taylor, Gail·2017·GCB Bioenergy
DOI 10.1111/gcbb.12347
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Abstract

The effect of a transition from grassland to second‐generation (2G) bioenergy on soil carbon and greenhouse gas (GHG) balance is uncertain, with limited empirical data on which to validate landscape‐scale models, sustainability criteria and energy policies. Here, we quantified soil carbon, soil GHG emissions and whole ecosystem carbon balance for short rotation coppice (SRC) bioenergy willow and a paired grassland site, both planted at commercial scale. We quantified the carbon balance for a 2‐year period and captured the effects of a commercial harvest in the SRC willow at the end of the first cycle. Soil fluxes of nitrous oxide (N 2 O) and methane (CH4) did not contribute significantly to the GHG balance of these land uses. Soil respiration was lower in SRC willow (912 ± 42 g C m−2 yr−1) than in grassland (1522 ± 39 g C m−2 yr−1). Net ecosystem exchange (NEE) reflected this with the grassland a net source of carbon with mean NEE of 119 ± 10 g C m−2 yr−1 and SRC willow a net sink, −620 ± 18 g C m−2 yr−1. When carbon removed from the ecosystem in harvested products was considered (Net Biome Productivity),SRC willow remained a net sink (221 ± 66 g C m−2 yr−1). Despite the SRC willow site being a net sink for carbon, soil carbon stocks (0–30 cm) were higher under the grassland. There was a larger NEE and increase in ecosystem respiration in the SRC willow after harvest; however, the site still remained a carbon sink. Our results indicate that once established, significant carbon savings are likely in SRC willow compared with the minimally managed grassland at this site. Although these observed impacts may be site and management dependent, they provide evidence that land‐use transition to 2G bioenergy has potential to provide a significant improvement on the ecosystem service of climate regulation relative to grassland systems.

AI snapshot

Written from the paper’s full text.

TL;DR

In a commercial-scale paired-site study in southern England, land-use change from minimally managed grassland to short rotation coppice willow improved the carbon balance: SRC willow was a net carbon sink while grassland was a net source over 2013–2014. Soil carbon stocks remained higher under grassland 7 years after conversion, but SRC willow still remained a net sink after accounting for harvested biomass.

Key findings

  • Soil respiration was lower in SRC willow (912 ± 42 g C m⁻² yr⁻¹) than in grassland (1522 ± 39 g C m⁻² yr⁻¹).
  • Mean NEE was 119 ± 10 g C m⁻² yr⁻¹ for grassland (net source) and −620 ± 18 g C m⁻² yr⁻¹ for SRC willow (net sink); after harvest, SRC willow remained a net sink with NBP of 221 ± 66 g C m⁻² yr⁻¹ despite removal of 399 ± 23 g C m⁻² yr⁻¹ in harvested biomass.
  • Soil carbon stocks (0–30 cm) were higher under grassland (63.4 ± 3.5 t C ha⁻¹) than SRC willow (42.6 ± 1.8 t C ha⁻¹; P < 0.001); at 0–100 cm, grassland was 107.6 ± 1.8 vs SRC willow 77.3 ± 7.7 t C ha⁻¹ (P = 0.062).
  • N₂O and CH₄ contributed little to the GHG balance: <4% for grassland and <1% for SRC willow; grassland emitted CH₄ (0.2 ± 0.2 g C m⁻² yr⁻¹) while SRC willow took up CH₄ (−0.2 ± 0.1 g C m⁻² yr⁻¹; P = 0.003).

Methods

  • Paired commercial-scale sites in south England: SRC willow (8.1 ha, planted June 2008) and permanent low-input grassland (7.4 ha); measurements ran November 2011–December 2014, with the whole-ecosystem carbon balance quantified for January 2013–December 2014 and a commercial willow harvest in April 2014.
  • Eddy covariance measured NEE; static chambers measured soil N₂O and CH₄; portable and automated chambers measured soil CO₂; biomass, litter fall/decomposition, and soil cores were used for carbon stocks and NPP.
  • Soil carbon stocks were calculated on an equivalent soil mass basis for 0–30 cm and 0–100 cm; analyses included t-tests and linear mixed models with treatment, year, soil temperature, and soil moisture as fixed effects.

Limitations

  • The paper states that root biomass was not measured in SRC willow, which may have underestimated the SRC willow sink postharvest, and that commercial-system restrictions limited experimental measurements.
  • The paper notes that the grassland management—cut grass retained on site with no carbon exports—may be uncommon, and that soil carbon at the SRC site may still be in recovery 7 years postconversion; sampling depth is also identified as a recurrent issue in soil carbon studies.
  • Evident from the text: this is a single paired-site comparison, so results are site- and management-dependent; eddy covariance data coverage was low (40% grassland and 37% SRC willow in 2013; 46% and 20% in 2014), energy balance closure was 73% for grassland and 77% for SRC willow, and the one-off postharvest N₂O peak suggests N₂O fluxes may require more intensive monitoring.

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

Integrity signals

Registry

Crossref · 10.1111/gcbb.12347

Cites

109 of 109 references verified0 citation errors · 0 not checkable

Statistics

3 tests recomputed · 1 with the reported and recomputed p on opposite sides of .05

Claims the paper makes

0 of 64 cited sources checked · 0 supported · 0 flagged

  • Findingown data

    Soil fluxes of nitrous oxide (N2O) and methane (CH4) did not contribute significantly to the greenhouse gas balance of the studied land uses.

    “Soil fluxes of nitrous oxide (N 2 O) and methane (CH 4 ) did not contribute significantly to the GHG balance of these land uses.”
    Quote in the paperNot a substantial claim
  • Findingown data

    Soil respiration was lower in short rotation coppice willow (912 ± 42 g C m−2 yr−1) than in grassland (1522 ± 39 g C m−2 yr−1).

    “Soil respiration was lower in SRC willow (912 Æ 42 g C m À2 yr À1 ) than in grassland (1522 Æ 39 g C m À2 yr À1 ).”
    Quote in the paperSubstantial claim
  • Findingown data

    The grassland was a net source of carbon with mean net ecosystem exchange of 119 ± 10 g C m−2 yr−1.

    “Net ecosystem exchange (NEE) reflected this with the grassland a net source of carbon with mean NEE of 119 Æ 10 g C m À2 yr À1”
    Quote in the paperSubstantial claim
  • Findingown data

    In year one (2013), the grassland was a net source of carbon, 246 ± 11 g C m−2 yr−1.

    “In year one (2013), the grassland was a net source of carbon, 246 Æ 11 g C m À2 yr À1 , whereas in year two (2014) it was a net sink, À9 Æ 16 g C m À2 yr À1 .”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The eddy covariance data retained after quality control and footprint analysis are representative of the full annual NEE at each site.
    • Rests on an assumption: The energy balance closure values (73% for grassland and 77% for SRC willow) are adequate for the flux measurements to be reliable.
  • Findingown data

    The short rotation coppice willow was a net sink of carbon with mean net ecosystem exchange of −620 ± 18 g C m−2 yr−1.

    “and SRC willow a net sink, À620 Æ 18 g C m À2 yr À1 .”
    Quote in the paperSubstantial claim
  • May combine two claims. 43
  • Classified as probably not a substantial claim. 32

  • May combine two claims.

    Findingown data

    In short rotation coppice willow after harvest, net ecosystem exchange was larger and ecosystem respiration increased.

    “There was a larger NEE and increase in ecosystem respiration in the SRC willow after harvest; however, the site still remained a carbon sink.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Despite the short rotation coppice willow site being a net sink for carbon, soil carbon stocks at 0-30 cm were higher under the grassland.

    “Despite the SRC willow site being a net sink for carbon, soil carbon stocks (0-30 cm) were higher under the grassland.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Over a 2-year period (2013-2014), including the harvest operation in SRC willow, during a side-by-side commercial-scale comparison, the SRC willow field was a net sink for carbon, whilst the minimally managed grassland field was a net source for carbon.

    “It has demonstrated that over a 2-year period (including the harvest operation in SRC willow), during a side-by-side commercial-scale comparison, an SRC willow field was a net sink for carbon, whilst the minimally managed grassland field was a net source for carbon.”
    • Also stated in: § Discussion · plain
      “For the grassland studied here, we found that over a 2-year measurement period, grassland was a net source for carbon and SRC willow was a net sink.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The adjacent minimally managed grassland field is a valid proxy for the pre-conversion land use at the SRC willow site.
    • Rests on an assumption: The 2-year measurement period (2013-2014) is representative of the longer-term carbon balance of the SRC willow rotation and the grassland.
    • Rests on an assumption: The eddy covariance data retained after quality control and footprint analysis are representative of the full annual NEE at each site.
    • Rests on an assumption: The energy balance closure values (73% for grassland and 77% for SRC willow) are adequate for the flux measurements to be reliable.

  • May combine two claims.

    Findingown data

    Soil carbon stocks were higher in the grassland than in the SRC willow for both the 0-30 and 0-100 cm profiles, but for the 0-100 cm profile this effect was only significant to P = 0.062, despite a clear trend.

    “Soil carbon stocks (Table 2) were higher in the grassland than in the SRC willow for both the 0-30 and 0-100 cm profiles, but for the latter this effect was only significant to P = 0.062, despite a clear trend.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The initial soil carbon stocks at the two sites were similar before land-use conversion.

  • May combine two claims.

    Findingown data

    SRC willow was a C sink for the 2-year duration of the experiment with a mean annual NEE of −620 ± 18 g C m−2 yr−1.

    “SRC willow was a C sink for the 2-year duration of the experiment with a mean annual NEE of À620 Æ 18 g C m À2 yr À1 (Fig. 7b).”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The eddy covariance data retained after quality control and footprint analysis are representative of the full annual NEE at each site.
    • Rests on an assumption: The energy balance closure values (73% for grassland and 77% for SRC willow) are adequate for the flux measurements to be reliable.

  • May combine two claims.

    Findingown data

    In 2014, Reco was larger than year one in SRC willow and both years in the grassland site at 1971 g C m−2 yr−1.

    “In 2014, R eco was larger than year one in SRC willow and both years in the grassland site at 1971 g C m À2 yr À1 .”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The eddy covariance data retained after quality control and footprint analysis are representative of the full annual NEE at each site.
    • Rests on an assumption: The energy balance closure values (73% for grassland and 77% for SRC willow) are adequate for the flux measurements to be reliable.

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

    Findingown data

    Relative humidity was not found to be a factor affecting NEE at either site.

    “Relative humidity was not found to be a factor affecting NEE at either site.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The eddy covariance data retained after quality control and footprint analysis are representative of the full annual NEE at each site.
    • Rests on an assumption: The energy balance closure values (73% for grassland and 77% for SRC willow) are adequate for the flux measurements to be reliable.

  • May combine two claims.

    Findingreasoning

    The site quickly became a net C sink again as there was a rapid re-sprout of willow stumps and understory vegetation.

    “The site quickly became a net C sink again as there was a rapid re-sprout of willow stumps and understory vegetation.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    N2O and CH4 emissions were generally low for both sites, contributing little to the total GHG balance for these contrasting land-use types in southern England.

    “N 2 O and CH 4 emissions were generally low for both sites, contributing little to the total GHG balance for these contrasting land-use types in southern England.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    For both sites, soil temperature significantly affected CH4 flux (P < 0.001), as well an interaction between soil moisture and soil temperature (P = 0.02).

    “For both sites, soil temperature significantly affected CH 4 flux (P < 0.001), as well an interaction between soil moisture and soil temperature (P = 0.02).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    CH4 was very low at both sites; however, there was a difference between the sites with an emission of 0.2 ± 0.2 g C m−2 yr−1 from grassland and uptake of −0.2 ± 0.1 g C m−2 yr−1 in SRC willow (P = 0.003).

    “CH 4 was also very low at both sites; however, there was a difference between the sites with an emission of 0.2 Æ 0.2 g C m À2 yr À1 from grassland and uptake of À0.2 Æ 0.1 g C m À2 yr À1 in SRC willow (P = 0.003; Table S6, Fig. S4; 0.7 Æ 0.7 and À0.7 Æ 0.4 g CO 2 -eq m À2 yr À1 for grass and SRC, respectively).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    N2O flux was significantly affected by year across both sites (P = 0.003), as well as an interaction between year and soil moisture (P = 0.007).

    “N 2 O flux was significantly affected by year across both sites (P = 0.003), as well as an interaction between year and soil moisture (P = 0.007).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    The grassland used initially for chamber measurements had similar carbon stocks to grassland in the upper 30 cm (61.2 ± 2.8 t C ha−1), with slightly less carbon in the 100 cm profile than the SRC willow (63.8 ± 4.1 t C ha−1).

    “The grassland which was used initially for chamber measurements had a similar carbon stocks to grassland in the upper 30 cm (61.2 Æ 2.8 t C ha À1 ), with slightly less carbon in the 100 cm profile than the SRC willow (63.8 Æ 4.1 t C ha À1 ; Table 2).”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The initial soil carbon stocks at the two sites were similar before land-use conversion.

  • May combine two claims.

    Findingown data

    Grassland was a net source of CH4, whereas SRC willow was a net sink, but the fluxes were small.

    “Interestingly, grassland was a net source of CH 4 , whereas SRC willow was a net sink, but the fluxes were small.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Mean NBP (2013-2014) was −118 ± 10 g C m−2 yr−1 for grassland and 221 ± 66 g C m−2 yr−1 for SRC willow, which, despite the removal of 399 g C m−2 yr−1 biomass from the SRC field, remained a net sink for carbon.

    “Thus, mean NBP (2013-2014) was À118 Æ 10 g C m À2 yr À1 for grassland and 221 Æ 66 g C m À2 yr À1 for SRC willow (mean Æ SD), which, despite the removal of 399 g C m À2 yr À1 biomass from the SRC field, remained a net sink for carbon.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    For our particular site, N2O and CH4 contributed little to the GHG balance of either land use and both were present in small quantities.

    “For our particular site, N 2 O and CH 4 contributed little to GHG balance of either land use and both were present in small quantities.”
    Quote in the paperSubstantial claim

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

    Findingown data

    There was a large one-off emission of N2O in June 2014, 2 months postharvest, which may have arisen as a result of the harvesting process.

    “There was a large one-off emission of N 2 O in June 2014, 2 months postharvest, which may have arisen as a result of the harvesting process (Fig. S3b).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    NEE decreased prior to harvest and then quickly increased after harvest.

    “The effect of the harvest on the NEE can be seen in Fig. 7b (dashed arrow indicated harvest date), where NEE decreased prior to harvest and then quickly increased after harvest.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    Mean N2O fluxes at both sites (2012-2014) were very low (within detection limit of equipment) with emissions of 1.2 ± 0.3 and 1.9 ± 0.6 g C m−2 yr−1 for grassland and SRC willow, respectively.

    “Mean N 2 O fluxes at both sites (2012-2014) were very low (within detection limit of equipment) with emissions of 1.2 Æ 0.3 and 1.9 Æ 0.6 g C m À2 yr À1 for grassland and SRC willow, respectively (Fig. S3; 4.4 Æ 1.1 and 7.0 Æ 2.2 g CO 2eq m À2 yr À1 for grass and SRC, respectively).”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    N2O and CH4 were not important contributors to the whole GHG balance of these two particular sites, accounting for less than 4% (3.4% N2O and 0.4% CH4) for grassland and less than 1% (0.77% N2O and 0.07% CH4) for SRC willow.

    “N 2 O and CH 4 were not important contributors to the whole GHG balance of these two particular sites, accounting for less than 4% (3.4% N 2 O and 0.4% CH 4 ) for grassland and less than 1% (0.77% N 2 O and 0.07% CH 4 ) for SRC willow.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    We observed a one-off peak in N2O emissions, 2 months postharvest, which was the largest emission observed across both sites for the duration of the experiment.

    “We also observed a oneoff peak in N 2 O emissions, 2 months postharvest, which was the largest emission, observed across both sites for the duration of the experiment.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    In the minimally managed site studied here, where harvested grass remained on the field, grassland was a net carbon source and SRC willow a net carbon sink, 7 years after land conversion.

    “In the minimally managed site studied here, where harvested grass remained on the field, we found that grassland was a net carbon source and SRC willow a net carbon sink, 7 years after land conversion.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The adjacent minimally managed grassland field is a valid proxy for the pre-conversion land use at the SRC willow site.
    • Rests on an assumption: The 2-year measurement period (2013-2014) is representative of the longer-term carbon balance of the SRC willow rotation and the grassland.

  • May combine two claims.

    Findingown data

    Soil carbon stocks to 0-100 cm were 107.6 ± 1.8 t C ha−1 under grassland, 77.3 ± 7.7 t C ha−1 under SRC willow, and 63.8 ± 4.1 t C ha−1 at the initial grassland site.

    “0-100 | 107.6 Æ 1.8 77.3 Æ 7.7 (10%) 63.8 Æ 4.1”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    In grassland, on average, 445 ± 48 g C m−2 yr−1 of organic material was left on the soil surface after mowing; in SRC willow, annual litter fall reached a maximum of 292 ± 12.5 g C m−2 yr−1 in 2013.

    “In grassland, on average, 445 Æ 48 g C m À2 yr À1 of organic material was left on the soil surface after mowing however in SRC willow, annual litter fall reached a maximum of 292 Æ 12.5 g C m À2 yr À1 in 2013.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingown data

    Grassland had significantly higher soil carbon stocks than the SRC willow up to 30 cm with a similar trend at 1 m depth.

    “Here, we found that grassland had significantly higher soil carbon stocks than the SRC willow up to 30 cm with a similar trend at 1 m depth.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The initial soil carbon stocks at the two sites were similar before land-use conversion.

  • May combine two claims.

    Findingcitation

    The observed increase in NEE is comparable to that observed by Zenone et al. (2015) for the 2nd year postestablishment of an SRC poplar plantation; indicating the effect of disturbance on NEE.

    “The observed increase in NEE is comparable to that observed by Zenone et al. (2015) for the 2nd year postestablishment of an SRC poplar plantation; indicating the effect of disturbance on NEE.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Zenone et al. (2015)

      Not checked in the free run.

  • May combine two claims.

    Findingown data

    At the two grasslands sites 59% and 96% carbon was stored in the top 30 cm, whereas in SRC willow 54% carbon was stored in the top 30 cm of the whole 100 cm profile.

    “We found that at the two grasslands sites 59% and 96% carbon was stored in the top 30 cm, whereas in SRC willow 54% carbon was stored in the top 30 cm of the whole 100 cm profile.”
    Quote in the paperNot a substantial claim
    • Rests on an assumption: The initial soil carbon stocks at the two sites were similar before land-use conversion.

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

    Findingown data

    The soil type at the SRC willow, grassland, and initial grassland sites was silt loam.

    “SRC willow | 0-15 | 7.38 59.44 33.19 Silt loam”
    • Also stated in: § Discussion · plain
      “Grass | 0-15 | 5.54 65.27 29.19 Silt loam”
    • Also stated in: § Discussion · plain
      “Initial grassland | 0-15 | 6.43 69.62 23.94 Silt loam”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data

    From our study, whilst there is an increase in Reco, and subsequently NEE after the harvest, within 3 weeks of harvest, the site was returned to being a sink for carbon.

    “From our study, we have shown that whilst there is an increase in R eco , and subsequently NEE after the harvest, within 3 weeks of harvest, the site was returned to being a sink for carbon.”
    Quote in the paperSubstantial claim

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    Gapfilling to estimate net ecosystem exchange and flux partitioning into ecosystem respiration and gross primary production were done according to standard Fluxnet methodology.

    “Gapfilling to estimate Net Ecosystem Exchange (NEE) and flux partitioning into Ecosystem Respiration (R eco ) and Gross Primary Production (GPP) were done according to the standard methodology used in Fluxnet (http://www.bgc-jena.mpg.de/~MDIwork/eddyproc/ ; Reichstein et al., 2005).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Reichstein et al., 2005

      Not checked in the free run.

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

    Premisecitation

    Dedicated second-generation nonfood feedstocks offer an opportunity to provide biomass for bioenergy-derived heat, electricity and biofuels without competing with land for food.

    “Dedicated second-generation (2G) nonfood feedstocks offer an opportunity to provide biomass for bioenergyderived heat, electricity and biofuels without competing with land for food (Dornburg et al., 2010;Stoof et al., 2015).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Dornburg et al., 2010

      Not checked in the free run.

    • cites Stoof et al., 2015

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Study design and conductcitation

    Total soil carbon stock for the 0-30 and 0-100 cm fractions was calculated on an equivalent soil mass basis.

    “Total soil carbon stock for the 0-30 and 0-100 cm fractions was calculated on an equivalent soil mass basis (Keith et al., 2015).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Keith et al., 2015

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Premisecitation

    Emissions of nitrous oxide and methane following management practices may offset approximately 70-80% of the net carbon sink in European grasslands.

    “Ciais et al. (2010) suggested that emissions of N 2 O and CH 4 following management practices may offset approximately 70-80% of the net carbon sink in European grasslands.”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Ciais et al. (2010)

      Not checked in the free run.

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

    Premisecitation

    Grassland types vary considerably, with significant differences in management that can dictate greenhouse gas balance.

    “partly reflecting the considerable variability that is found amongst grassland types with significant differences in management which can dictate GHG balance (Soussana et al., 2010).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Soussana et al., 2010

      Not checked in the free run.

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

    Study design and conductreasoning

    Soil CO2 flux may be overestimated because small amounts of shoot vegetation remained inside the sampling chamber.

    “However, small amounts of shoot vegetation remained inside the chamber, and therefore, soil CO 2 flux may be overestimated.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductreasoning

    Eddy covariance towers were established in the north-easterly corner of the grassland and short rotation coppice willow to ensure enough fetch.

    “The dominant wind direction is from the southwest; therefore, eddy covariance towers were established in the north-easterly corner of the grassland and SRC willow in order to ensure enough fetch (Fig. 2).”
    Quote in the paperSubstantial claim

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

    Study design and conductreasoning

    Net ecosystem exchange uncertainty was computed according to FLUXNET methodology, while error terms could not be calculated for ecosystem respiration and gross primary production because they are modelled terms.

    “NEE uncertainty (i.e. standard deviation) was computed according to the FLUXNET methodology using the online software, whilst error terms were unable to be calculated for R eco and GPP as these are modelled terms.”
    Quote in the paperNot a substantial claim

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

    Study design and conductown data

    Data from automated soil chambers were used to validate periodic soil CO2 flux measurements.

    “Data from automated chambers were used to validate periodic measurements.”
    Quote in the paperNot a substantial claim

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

    Study design and conductreasoning

    Most eddy covariance data were discarded during night-time because the assumptions used for eddy covariance measurements, such as turbulence, were not fulfilled.

    “Most of the data were discarded during nigh-time as the assumptions using for eddy covariance measurements (i.e.turbulence) were not fulfilled.”
    Quote in the paperNot a substantial claim

  • Classified as probably not a substantial claim.

    Study design and conductown data

    Destructive sampling of short rotation coppice willow prior to commercial harvest allowed estimation of actual biomass from stem:volume index values.

    “Destructive sampling of SRC willow was also conducted prior to commercial harvest in November 2013, to allow an estimation of actual biomass from stem : volume index values.”
    Quote in the paperSubstantial claim

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

    Premisecitation

    Methodological considerations such as soil sampling depth and calculation of soil carbon stocks using a fixed depth method may affect conclusions drawn about land-use change.

    “Additionally, there are methodological considerations which may affect the conclusions drawn about LUC, such as soil sampling depth (Dolan et al., 2006;Blanco-Canqui & Lal, 2008) and calculation of soil carbon stocks using a fixed depth method (Walter et al., 2015).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Dolan et al., 2006

      Not checked in the free run.

    • cites Blanco-Canqui & Lal, 2008

      Not checked in the free run.

    • cites Walter et al., 2015

      Not checked in the free run.

  • Classified as probably not a substantial claim. May combine two claims.

    Study design and conductnone given

    Five plots were randomly selected in each field for soil carbon sampling, with three within-plot soil cores taken to 30 cm depth.

    “Five plots were randomly selected in each field; from each of these plots, three within-plot soil cores were taken using a split-tube soil sampler (Eijkelkamp Agrisearch Equipment BV, Giesbeek, the Netherlands) with an inner diameter of 4.8 cm to a depth of 30 cm.”
    Quote in the paperSubstantial claim

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

    Study design and conductown data

    The analytical precision of the gas chromatograph for standards at ambient concentration was approximately 2%, using two standard deviations as a measure of mean error.

    “The analytical precision of the GC for standards at ambient concentration was approximately 2%, using two standard deviations as a measure of mean error.”
    Quote in the paperNot a substantial claim

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

    Study design and conductnone given

    Eight plots were established in random locations in the short rotation coppice willow and grassland, with randomization within a few metres of field edges to avoid edge effects.

    “Eight plots were established in random locations in the SRC willow and grassland in November 2011 to measure soil GHGs, soil chemistry, aboveground and belowground biomass, litter fall and litter decomposition (Fig. 2).Randomization took place within a few metres of field edges to avoid any edge effects.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S2 (checkable), S3 (load-bearing).

    Premisecitation

    Outputs from models parameterized for nonbioenergy exemplar arable, grass and tree ideotypes may be used to develop sustainability criteria and policy instruments.

    “outputs from such models, often parameterized for nonbioenergy 'exemplar' arable, grass and tree ideotypes, may be used to develop sustainability criteria and policy instruments (Creutzig et al., 2012;Buchholz et al., 2014).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Creutzig et al., 2012

      Not checked in the free run.

    • cites Buchholz et al., 2014

      Not checked in the free run.

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

    Premisecitation

    Former land use is the most important consideration determining whether a transition to second-generation bioenergy will result in a net source or net sink of carbon.

    “St. Clair et al. (2008) found that former land use is the most important consideration determining whether a transition to 2G bioenergy will result in a net source or net sink of carbon.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites St. Clair et al. (2008)

      Not checked in the free run.

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

    Premisecitation

    Reductions in other greenhouse gas emissions have been reported for land-use change from arable to second-generation bioenergy.

    “Similarly, reductions in other GHG emissions have also been reported for LUC from arable to 2G bioenergy (Drewer et al., 2012;Gauder et al., 2012;Zona et al., 2013a;Palmer et al., 2014)”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Drewer et al., 2012

      Not checked in the free run.

    • cites Gauder et al., 2012

      Not checked in the free run.

    • cites Zona et al., 2013a

      Not checked in the free run.

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

    Premisecitation

    Grasslands can vary in both space and time for GHG emissions and carbon balance.

    “Grasslands can vary in both space and time for GHG emissions and carbon balance (Soussana et al., 2007;Imer et al., 2013), as found here where the grassland in this study was a net source of carbon in 2013 and a net sink in 2014, possibly attributable to the higher temperatures observed in January-March 2014 compared to 2013.”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Soussana et al., 2007

      Not checked in the free run.

    • cites Imer et al., 2013

      Not checked in the free run.

  • May combine two claims.

    Interpretationreasoning

    Management of the grazing and mowing regime might be central to the carbon balance of such a system and determine net source or sink status.

    “Thus, we can conclude that management of the grazing and mowing regime might be central to the carbon balance of such a system and determine net source or sink status.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    In a UK context, conversion of semipermanent, permanent or managed grassland to bioenergy cropping systems represents one of the most significant potential land-use transitions.

    “In a UK context, conversion of semipermanent, permanent or managed grassland to bioenergy cropping systems represents one of the most significant potential land-use transitions, since grassland is a considerable part of the UK landscape (4-5 9 10 6 ha; DEFRA et al., 2007) and because management of grasslands can vary widely in the UK, particularly with respect to fertilizer input and grazing.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites DEFRA et al., 2007

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    These results coupled with the potential carbon and GHG savings made by replacing fossil fuels demonstrate the potential of bioenergy for climate change mitigation and improved energy security.

    “These results coupled with the potential carbon and GHG savings made by replacing fossil fuels demonstrate the potential of bioenergy for climate change mitigation and improved energy security (Cannell, 2003;Styles & Jones, 2007).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Cannell, 2003

      Not checked in the free run.

    • cites Styles & Jones, 2007

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    The combination of increased temperature with an increase in winter rainfall (which resulted in increased soil moisture) could explain the higher aboveground biomass in grassland and consequently why the site was a net sink in 2014.

    “This combination of increased temperature with an increase in winter rainfall (which resulted in increased soil moisture) could explain the higher aboveground biomass in grassland and consequently why the site was a net sink in 2014 (Pitt & Heady, 1978).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Pitt & Heady, 1978

      Not checked in the free run.

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

    Premisecitation

    There are large uncertainties surrounding the overall GHG balance of temperate grasslands.

    “As well as large variability, there are also large uncertainties surrounding the overall GHG balance of temperate grasslands (Janssens et al., 2003).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Janssens et al., 2003

      Not checked in the free run.

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

    Premisecitation

    SRC willow has been found to be a net sink for CH4 in other studies to a similar extent to that found here.

    “SRC willow has been found to be a net sink for CH 4 in other studies to a similar extent to that found here (Drewer et al., 2012;Kern et al., 2012).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Drewer et al., 2012

      Not checked in the free run.

    • cites Kern et al., 2012

      Not checked in the free run.

  • May combine two claims.

    Interpretationown data

    This land-use change provided bioenergy as a net provisioning ecosystem service and was able to contribute to improved climate regulation through the generation of a net carbon sink relative to the original land use.

    “This suggests that not only did this LUC provide bioenergy as a net provisioning ecosystem service, but was also able to contribute to improved climate regulation through the generation of a net carbon sink relative to the original land use.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The adjacent minimally managed grassland field is a valid proxy for the pre-conversion land use at the SRC willow site.
    • Rests on an assumption: The 2-year measurement period (2013-2014) is representative of the longer-term carbon balance of the SRC willow rotation and the grassland.

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

    Premisecitation

    Heterotrophic respiration can vary from 10% to 90% depending on vegetation type and time of year.

    “Since heterotrophic respiration can vary from 10% to 90% depending on vegetation type and time of year (Hanson et al., 2000), our data fall within this wide range.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Hanson et al., 2000

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    Chronosequence data suggest that after initial conversion from grassland to SRC willow, there can be a loss of soil carbon for up to 5 years, which is followed by recovery up to 19 years.

    “Chronosequence data also suggest that after initial conversion from grassland to SRC willow, there can be a loss of soil carbon for up to 5 years, which is followed by recovery up to 19 years (Pacaldo et al., 2013b).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Pacaldo et al., 2013b

      Not checked in the free run.

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

    Premisecitation

    Other studies have observed little effect of harvest on N2O emissions from SRC cultures.

    “In contrast, other studies have observed little effect of harvest on N 2 O emissions from SRC cultures (Zona et al., 2013b).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Zona et al., 2013b

      Not checked in the free run.

  • May combine two claims.

    Premisecitation

    LCA findings have shown that whilst the harvest can increase emissions due to the harvest machinery, the carbon sink created by SRC willow is able to offset these emissions and result in a negative GHG balance (reported in the range of −138 to −53 kg CO2-eq per odt biomass).

    “LCA findings have shown that whilst the harvest can increase emissions due to the harvest machinery, the carbon sink created by SRC willow is able to offset these emissions and result in a negative GHG balance (reported in the range of À138 to À53 kg CO 2 -eq.per odt biomass; Caputo et al., 2014).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Caputo et al., 2014

      Not checked in the free run.

  • May combine two claims.

    Interpretationown data

    There is evidence that this land-use change may result in climate mitigation advantages and may be considered a viable bioenergy option for the future.

    “Whilst grasslands have been shown to be highly variable, there is evidence that this LUC may result in climate mitigation advantages and may be considered a viable bioenergy option for the future.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: The adjacent minimally managed grassland field is a valid proxy for the pre-conversion land use at the SRC willow site.
    • Rests on an assumption: The 2-year measurement period (2013-2014) is representative of the longer-term carbon balance of the SRC willow rotation and the grassland.

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

    Interpretationreasoning

    It is also possible that there was some compaction due to the harvest machinery which can cause a reduction in soil porosity, in turn resulting in increased N2O emissions.

    “It is also possible that there was some compaction due to the harvest machinery which can cause a reduction in soil porosity, in turn resulting in increased N 2 O emissions.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Study design and conductcitation

    The calculated values in this study are in line with empirical findings recently published by Cunniff et al. (2015); therefore, we are able to use these estimates with some confidence.

    “However, the calculated values in this study are in line with empirical findings recently published by Cunniff et al. (2015); therefore, we are able to use these estimated with some confidence.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Cunniff et al. (2015)

      Not checked in the free run.

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

    Premisecitation

    Walter et al. (2015) suggested that the transition from grassland to SRC results in a redistribution of carbon through the profile, despite total SOC stock not being significantly different.

    “Walter et al. (2015), from a chronosequence of SRC sites, suggested that this transition results in a redistribution of carbon through the profile, despite total SOC stock not being significantly different.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Walter et al., 2015

      Not checked in the free run.

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

    Premisecitation

    Soil N2O fluxes are known to vary spatially and temporally and to arise quickly after changes in rainfall, temperature and management.

    “Soil N 2 O fluxes are known to vary spatially and temporally and to arise quickly after changes in rainfall, temperature and management (Skiba & Smith, 2000).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Skiba & Smith, 2000

      Not checked in the free run.

  • May combine two claims.

    Interpretationcitation

    The higher soil carbon observed in grassland may be attributable to the amount of organic material left on the soil surface after mowing and may not be widely representative of much managed rotational grassland.

    “At this particular site, the higher soil carbon observed in grassland may be attributable to the amount of organic material left on the soil surface after mowing (Post & Kwon, 2000) and may not be widely representative of much managed rotational grassland.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Post & Kwon, 2000

      Not checked in the free run.

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

    Premisecitation

    There have been reports in the literature of both increased soil carbon under SRC compared to grassland, as well as others which found no significant difference.

    “There have been reports in the literature of both increased soil carbon under SRC compared to grassland (Zan et al., 2001;Arevalo et al., 2009), as well as others which have found no significant difference (Grigal & Berguson, 1998;Walter et al., 2015).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Zan et al., 2001

      Not checked in the free run.

    • cites Arevalo et al., 2009

      Not checked in the free run.

    • cites Grigal & Berguson, 1998

      Not checked in the free run.

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

    Premisecitation

    A single large emission can account for a large proportion of total N2O fluxes over a measurement period.

    “N 2 O emissions, therefore, require more intense monitoring to be able to capture these emissions, since a single large emission can account for a large proportion of total N 2 O fluxes over a measurement period (Zona et al., 2013b).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Zona et al., 2013b

      Not checked in the free run.

67 of 67

  • The paper relies on this without support.

    The paired grassland site represents the counterfactual land use that the short rotation coppice willow site would have had without conversion.

    “This study was conducted in the south of England (50°58 0 N, 0°27 0 W) in an established SRC willow plantation (8.1 ha) and permanent grassland with low inputs (7.4 ha).”
    “Mixed commercial genotypes of SRC willow were planted in June 2008 on a grassland field, previously defined as set-aside (2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007) at a density of 15 000 stems ha À1 in double rows with distances of 0.75 m in the row and 1.4 m between the rows (Forestry Commission, 2002).”

  • The paper relies on this without support.

    Soil carbon stocks measured once in October 2012 are representative of the land-use difference over the study period.

    “Samples were only taken once during the experiment in October 2012.”

  • The paper relies on this without support.

    The adjacent minimally managed grassland field is a valid proxy for the pre-conversion land use at the SRC willow site.

    “It has demonstrated that over a 2-year period (including the harvest operation in SRC willow), during a side-by-side commercial-scale comparison, an SRC willow field was a net sink for carbon, whilst the minimally managed grassland field was a net source for carbon.”

  • The paper relies on this without support.

    The 2-year measurement period (2013-2014) is representative of the longer-term carbon balance of the SRC willow rotation and the grassland.

    “It has demonstrated that over a 2-year period (including the harvest operation in SRC willow), during a side-by-side commercial-scale comparison, an SRC willow field was a net sink for carbon, whilst the minimally managed grassland field was a net source for carbon.”

  • The paper relies on this without support.

    The eddy covariance data retained after quality control and footprint analysis are representative of the full annual NEE at each site.

    “For the eddy covariance data, after quality control checks and footprint analysis the data remaining were 40% for grassland and 37% for SRC willow in 2013.”

  • The paper relies on this without support.

    The energy balance closure values (73% for grassland and 77% for SRC willow) are adequate for the flux measurements to be reliable.

    “The energy balance closure for the sites, based on measured data only, was a 73% for grassland (Fig. 6a) and 77% for SRC willow (Fig. 6b).”

  • The paper relies on this without support.

    The initial soil carbon stocks at the two sites were similar before land-use conversion.

    “Soil carbon stocks (Table 2) were higher in the grassland than in the SRC willow for both the 0-30 and 0-100 cm profiles, but for the latter this effect was only significant to P = 0.062, despite a clear trend.”
7 of 7

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?

Statistics that don’t add up

Each reported p-value recomputed from its test statistic and degrees of freedom.

  • Inconsistent p-value across alpha = .05: t (4) = À3.84,p = .062

    Major

    The paper reports p = .062 here; recomputing from the test statistic and its degrees of freedom gives p = .018 (two-tailed). The two fall on opposite sides of alpha = .05. The check cannot tell whether the statistic or the p-value is the misprint.

    Reported p = .062 · recomputed p = .018

1 of 1

Statistics recomputed

Every reported test result, recomputed from its test statistic and degrees of freedom. A result shows as not adding up only once an independent check has confirmed it.

  • Doesn’t add upt(4) = -3.84reported p = .062 · recomputed p = .018The two fall on opposite sides of .05

    “t (4) = À3.84,p = .062”

  • Consistentt(4) = -0.06reported p = .95 · recomputed p = .955

    “t (4) = À0.06,p = .95”

  • Consistentt(28) = -5.3reported p < .001 · recomputed p < .001

    “t (28) = À5.30,p < .001”

3 of 3

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.

  • Uncertainty for the same grassland mowing amount differs

    Minor

    The paper gives two different uncertainty values, 68 and 48 g C m À2 yr À1, for the same mean grassland mowing amount of 445 g C m À2 yr À1.

1 of 1

Cites

Flagged first, then by citations

Research works printed but not linked: 7

  1. DECC, 2014, Life Cycle Impacts of Biomass Electricity in 2020
  2. DEFRA, 2014, Area of Crops Grown for Bioenergy in England and the UK: 2008 – 2013
  3. Forestry Commission, 2002, Practice Note: Establishment and Management of Short Rotation Coppice. FCPN7 (REVISED)
  4. IPCC(2007a)Fourth Assessment Report Working Group III Report ‘‘Mitigation of Climate Change’’.MetzB DavidsonOR BoschPR DaveR MeyerLA(eds) Cambridge University Press Cambridge United Kingdom and New York NY USA.
  5. IPCC(2007b)Climate Change 2007: Working Group I: The Physical Science Basis.SolomonS QinD ManningMet al. (eds) Cambridge University Press Cambridge United Kingdom and New York NY USA.
  6. 10.5194/bgd-12-8035-2015 · DOI
  7. Souza GM, 2015, Bioenergy & Sustainability: Bridging the Gaps

Cited by

Sorted by citations

Related

Authors
Harris, Z. M., Alberti, G., Viger, M., Jenkins, J. R., Rowe, R., McNamara, N. P., & Taylor, G.
Affiliations
  • University of Southampton (GB)
  • University of Udine (IT)
  • UK Centre for Ecology & Hydrology (GB)
Corresponding author
Taylor, Gail
ORCID
Venue
GCB Bioenergy
Publisher
Wiley
Published
2016-04-24
Volume
9
Issue
2
Pages
469-484
ISSN
  • 1757-1693 (ISSN-L)
  • 1757-1707
DOI
10.1111/gcbb.12347
OpenAlex
W2336487249
Semantic Scholar
1eae8047579b3b8e3b0829dd5156c932afdf32d2
Cited by
40
References
108
Citations by year
2026: 1 · 2025: 1 · 2024: 8 · 2023: 3 · 2022: 6 · 2021: 6 · 2020: 5 · 2019: 2 · 2018: 3 · 2017: 5
FWCI
6.82
Type
journal article
Language
en
Open access
Licence
Locations
  • GCB Bioenergy (publishedVersion, cc-by)
  • NERC Open Research Archive (Natural Environment Research Council) (acceptedVersion)
  • ePrints Soton (University of Southampton) (acceptedVersion)
  • Spiral (Imperial College London) (submittedVersion, other-oa)
Funders
  • Natural Environment Research Council (NE/H010742/1)
  • UK Energy Research Centre (NE/H013237/1)
  • Seventh Framework Programme
Topics
  • Life Sciences › Agricultural and Biological Sciences › Agronomy and Crop Science › Bioenergy crop production and management
  • Life Sciences › Agricultural and Biological Sciences › Soil Science › Soil Carbon and Nitrogen Dynamics
  • Physical Sciences › Environmental Science › Global and Planetary Change › Land Use and Ecosystem Services
Keywords
land use change, short rotation coppice willow, grassland, soil carbon, greenhouse gas balance, net ecosystem exchange, soil respiration, net biome production, carbon sink, harvest effects, climate regulation, ecosystem services

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 2026-10-10.

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

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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