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Cited by 380Soil Carbon and Nitrogen DynamicsAgricultural Science and FertilizationThermochemical Biomass Conversion Processes

A review on biochar modulated soil condition improvements and nutrient dynamics concerning crop yields: Pathways to climate change mitigation and global food security

Purakayastha, T.J., Bera, T., Bhaduri, Debarati, Sarkar, Binoy, Mandal, Sanchita, Wade, Peter, Kumari, Savita, Biswas, Sunanda +3 more·2019·Chemosphere
DOI 10.1016/j.chemosphere.2019.03.170
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Abstract

The beneficial role of biochar on improvement of soil quality, C sequestration, and enhancing crop yield is widely reported. As such there is not much consolidated information available linking biochar modulated soil condition improvement and soil nutrient availability on crop yields. The present review paper addresses the above issues by compilation of world literature on biochar and a new dimension is introduced in this review by performing a meta-analysis of published data by using multivariate statistical analysis. Hence this review is a new in its kind and is useful to the broad spectrum of readers. Generally, alkalinity in biochar increases with increase in pyrolysis temperature and majority of the biochar is alkaline in nature except a few which are acidic. The N content in many biochar was reported to be more than 4% as well as less than 0.5%. Poultry litter biochar is a rich source of P (3.12%) and K (7.40%), while paper mill sludge biochar is higher in Ca content (31.1%) and swine solids biochar in Zn (49810 mg kg-1), and Fe (74800 mg kg-1) contents. The effect of biochar on enhancing soil pH was higher in Alfisol, Ferrosol and Acrisol. Soil application of biochar could on an average increase (78%), decrease (16%), or show no effect on crop yields under different soil types. Biochar produced at a lower pyrolysis temperature could deliver greater soil nutrient availabilities than that prepared at higher temperature. Principal component analysis (PCA) of available data shows an inverse relationship between [pyrolysis temperature and soil pH], and [biochar application rate and soil cation exchange capacity]. The PCA also suggests that the original soil properties and application rate strongly control crop yield stimulations via biochar amendments. Finally, biochar application shows net soil C gains while also serving for increased plant biomass production that strongly recommends biochar as a useful soil amendment. Therefore, the application of biochar to soils emerges as a 'win-win strategy' for sustainable waste management, climate change mitigation and food security.

AI snapshot

Written from the paper’s full text.

TL;DR

This review compiles global literature and performs PCA-based meta-analysis on biochar effects on soil properties, nutrient dynamics, and crop yields. It concludes that biochar can improve soil quality, nutrient availability, and C sequestration, but yield responses vary strongly with soil type, feedstock, pyrolysis temperature, and application rate.

Key findings

  • Biochar properties vary widely: C ranged from 19.2% to 81.2%; N was sometimes >4% and sometimes <0.5%; poultry litter biochar was rich in P (3.12%) and K (7.40%), paper mill sludge biochar had the highest Ca (31.1%), and swine solids biochar had high Zn (49810 mg kg⁻¹) and Fe (74800 mg kg⁻¹).
  • Soil application of biochar could on average increase crop yields by 78%, decrease them by 16%, or show no effect depending on soil type; across studies, yields were enhanced by 4–144% or declined by 4–24%.
  • Biochar produced at lower pyrolysis temperature could deliver greater soil nutrient availability than biochar produced at higher temperature; PCA showed the first two components explained 74.3% of variance for soil chemical properties and 76.8% for crop yields, with original soil properties and application rate strongly controlling yield stimulation.
  • Biochar application showed net soil C gains while increasing plant biomass production, supporting its use as a “win-win strategy” for waste management, climate change mitigation, and food security.

Methods

  • Literature was searched via Google Scholar and direct journal consultation using keywords such as “biochar,” “characteristics,” “availability of nutrients,” and “yield,” compiling published data on biochar nutrient contents, soil physical/chemical properties, N, P, K, secondary and micronutrient dynamics, and crop yields across soil orders.
  • Two principal component analyses (PCAs) were performed using PAST version 3.18; variables were normalized by subtracting the mean and dividing by standard deviation, and PCA used the correlation matrix.
  • The soil chemical properties PCA analysed 48 cases for change in soil pH and CEC; the crop yield PCA analysed 36 cases for yield change.

Limitations

  • The paper states that low sample numbers and high diversity within samples mean not much information may be derived from the temperature–application rate–yield dataset by PCA, and 23.2% unexplained variance was neglected.
  • The paper notes that mechanisms for biochar effects on soil P and K transformations are not clear, direct evidence of nutrient availability from biochar to crops is scarce, and information on alkaline soils in arid and semiarid regions is limited; long-term field-scale trials are needed.
  • Evident from the text: the review/meta-analysis depends on heterogeneous published studies with differing soils, feedstocks, pyrolysis conditions, application rates, and units, which limits causal inference.

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

Integrity signals

Registry

Crossref · 10.1016/j.chemosphere.2019.03.170

Cites

193 of 193 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 265 cited sources checked · 0 supported · 0 flagged

  • Findingnone given
    § ACCEPTED MANUSCRIPT · p. 18

    In Planosol, even at very high rate of biochar application (90-100 Mg ha-1), the per cent increase in soil pH was only between 22-33%.

    “In Planosol, even at very high rate of biochar application (90˗100 Mg ha -1 ), the per cent increase in soil pH was only between 2233%.”
    Quote in the paperNot a substantial claim
  • Findingcitation
    § ACCEPTED MANUSCRIPT · p. 19

    CEC increased in all cases except one where the soil was a calcarosol.

    “As shown in Table 2, CEC increased in all cases except one where the soil was a calcarosol (van Zwieten et al. 2010).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites van Zwieten et al. 2010 source

      Not checked in the free run.

  • Findingreasoning
    § ACCEPTED MANUSCRIPT · p. 18

    The per cent increase in soil pH due to biochar application was highest (>50%) in Alfisol with biochar application rates ranging from 25-50 Mg ha-1.

    “The per cent increase in soil pH due to biochar application was the highest (˃ 50%) in Alfisol with biochar application rates ranging from 25˗50 Mg ha -1”
    Quote in the paperNot a substantial claim
  • Findingown data
    § ACCEPTED MANUSCRIPT · p. 18

    The per cent increase in soil pH was between 4-50% in Alfisol, Anthrosol, Cambisol, Mollisol, Inceptisol and Oxisolis with biochar application rates ranging from 4-72 Mg ha-1.

    “while the increase was between 4 ˗ 50% in Alfisol, Anthrosol, Cambisol, Mollisol, Inceptisol and Oxisolis with biochar application rates ranging from 4˗72 Mg ha -1 (Fig. 2).”
    Quote in the paperNot a substantial claim
  • Findingnone given
    § ACCEPTED MANUSCRIPT · p. 18

    In calcareous soils, and some Cambisol and Mollisol, no effect of biochar on soil pH was observed.

    “Interestingly, in calcareous soils, and some Cambisol and Mollisol, no effect of biochar on soil pH was observed (Fig. 2).”
    Quote in the paperNot a substantial claim
  • May combine two claims. 96
  • The quote only partly states this claim. 23
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    Findingcitation
    § ACCEPTED MANUSCRIPT · p. 23

    When biochar was added to soil, gross N mineralization, recalcitrant nitrogen fraction and labile N fraction were stimulated.

    “When biochar was added to soil, gross N mineralization, recalcitrant nitrogen fraction and labile N fraction were found to be stimulated (Table 3).”
    Quote in the paperSubstantial claim

  • May combine two claims. The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 29

    Total P content ranged 16-9500 mg kg-1 for crop residue biochar, 5-6000 mg kg-1 for wood biochar, 2950-7.40x10^4 mg kg-1 for manure biochar, and 90-23300 mg kg-1 for waste material biochar.

    “The total P content ranged 16-9500 mg kg -1 for crop residue biochar, 5-6000 mg kg -1 for wood biochar, 29507.40x10 4 mg kg -1 for manure biochar, and 90-23300 mg kg -1 for waste material biochar (Table 3).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Table 3

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    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    For soil chemical properties, the second principal component explains 35.0% of the variance.

    “| 2 | 1.40 | 35.0 | 74.3 | | 30.9 | | 45.9 |”
    Quote in the paperNot a substantial claim

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    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of soil chemical properties, the first principal component has a loading of 0.43 on change in pH.

    “| 1 | 0.27 | 0.64 | 0.43 | 0.58 | -0.67 | 0.48 | 0.57 |”
    Quote in the paperNot a substantial claim

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    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of crop yields, the first principal component has a loading of 0.48 on application rate.

    “| 1 | 0.27 | 0.64 | 0.43 | 0.58 | -0.67 | 0.48 | 0.57 |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of soil chemical properties, the fourth principal component has a loading of 0.63 on change in CEC.

    “| 4 | 0.46 | -0.54 | -0.32 | 0.63 | - | - | - |”
    Quote in the paperNot a substantial claim

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    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    For crop yields, the second principal component explains 30.9% of the variance.

    “| 2 | 1.40 | 35.0 | 74.3 | | 30.9 | | 45.9 |”
    Quote in the paperNot a substantial claim

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    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of soil chemical properties, the first principal component has a loading of 0.64 on application rate.

    “| 1 | 0.27 | 0.64 | 0.43 | 0.58 | -0.67 | 0.48 | 0.57 |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of soil chemical properties, the third principal component has a loading of -0.29 on change in CEC.

    “| 3 | 0.51 | 0.48 | -0.65 | -0.29 | 0.74 | 0.37 | 0.56 |”
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  • Probably not a substantial claim: may not pass S3 (load-bearing).

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    For soil chemical properties, the first principal component explains 39.3% of the variance.

    “| 1 | 1.57 | 39.3 | 39.3 | 1.38 | 45.9 | | 45.9 |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of soil chemical properties, the fourth principal component has a loading of -0.54 on application rate.

    “| 4 | 0.46 | -0.54 | -0.32 | 0.63 | - | - | - |”
    Quote in the paperNot a substantial claim

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

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 45

    The first principal component for crop yields accounted for 45.9% of the variance in the data.

    “The first principal component, accounting for 45.9% of the variance in the data”
    Quote in the paperNot a substantial claim

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    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of crop yields, the first principal component has a loading of 0.57 on yield.

    “| 1 | 0.27 | 0.64 | 0.43 | 0.58 | -0.67 | 0.48 | 0.57 |”
    Quote in the paperNot a substantial claim

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

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    For crop yields, the first principal component explains 45.9% of the variance.

    “| 1 | 1.57 | 39.3 | 39.3 | 1.38 | 45.9 | | 45.9 |”
    Quote in the paperNot a substantial claim

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

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of crop yields, the first principal component has a loading of -0.67 on temperature.

    “| 1 | 0.27 | 0.64 | 0.43 | 0.58 | -0.67 | 0.48 | 0.57 |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of soil chemical properties, the second principal component has a loading of -0.43 on change in CEC.

    “| 2 | 0.67 | -0.25 | 0.54 | -0.43 | 0.06 | 0.79 | -0.61 |”
    Quote in the paperNot a substantial claim

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

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 45

    For crop yields, the total variance explained by the first two principal components was 76.8%.

    “In this case, the total variance explained by the first two principal components was 76.8%.”
    Quote in the paperNot a substantial claim

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

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    For crop yields, the first two principal components cumulatively explain 76.8% of the variance.

    “| 3 | 0.62 | 15.5 | 89.8 | 0.93 0.70 | 23.2 | 76.8 100 | 45.9 |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of soil chemical properties, the second principal component has a loading of 0.67 on temperature.

    “| 2 | 0.67 | -0.25 | 0.54 | -0.43 | 0.06 | 0.79 | -0.61 |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of soil chemical properties, the third principal component has a loading of -0.65 on change in pH.

    “| 3 | 0.51 | 0.48 | -0.65 | -0.29 | 0.74 | 0.37 | 0.56 |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of soil chemical properties, the fourth principal component has a loading of -0.32 on change in pH.

    “| 4 | 0.46 | -0.54 | -0.32 | 0.63 | - | - | - |”
    Quote in the paperNot a substantial claim

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

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of soil chemical properties, the first principal component has a loading of 0.27 on temperature.

    “| 1 | 0.27 | 0.64 | 0.43 | 0.58 | -0.67 | 0.48 | 0.57 |”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data
    § 9. Principal component analysis to evaluate biochar's effect on soil chemical properties and crop yields · p. 44

    The second principal component for soil chemical properties shows an inverse relationship between pyrolysis temperature and pH, and loading rate and CEC.

    “The latter principal component shows an inverse relationship between [pyrolysis temperature and pH] and [loading rate and CEC].”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of soil chemical properties, the second principal component has a loading of -0.25 on application rate.

    “| 2 | 0.67 | -0.25 | 0.54 | -0.43 | 0.06 | 0.79 | -0.61 |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of soil chemical properties, the third principal component has a loading of 0.51 on temperature.

    “| 3 | 0.51 | 0.48 | -0.65 | -0.29 | 0.74 | 0.37 | 0.56 |”
    Quote in the paperNot a substantial claim

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

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of soil chemical properties, the first principal component has a loading of 0.58 on change in CEC.

    “| 1 | 0.27 | 0.64 | 0.43 | 0.58 | -0.67 | 0.48 | 0.57 |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of soil chemical properties, the third principal component has a loading of 0.48 on application rate.

    “| 3 | 0.51 | 0.48 | -0.65 | -0.29 | 0.74 | 0.37 | 0.56 |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of soil chemical properties, the second principal component has a loading of 0.54 on change in pH.

    “| 2 | 0.67 | -0.25 | 0.54 | -0.43 | 0.06 | 0.79 | -0.61 |”
    Quote in the paperNot a substantial claim

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

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    For soil chemical properties, the first two principal components cumulatively explain 74.3% of the variance.

    “| 2 | 1.40 | 35.0 | 74.3 | | 30.9 | | 45.9 |”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 45

    The second principal component for crop yields was dominated by application rate and yield, which display an inverse relationship.

    “and was instead dominated by application rate and yield, which display an inverse relationship.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of soil chemical properties, the fourth principal component has a loading of 0.46 on temperature.

    “| 4 | 0.46 | -0.54 | -0.32 | 0.63 | - | - | - |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing), S4 (based). The quote only partly states this claim.

    Findingnone given
    § ACCEPTED MANUSCRIPT · p. 45

    The highest pairwise correlation exists between biochar loadings and change in CEC of soil.

    “and (ii) between biochar loadings and change in CEC of soil.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of crop yields, the second principal component has a loading of 0.06 on temperature.

    “| 2 | 0.67 | -0.25 | 0.54 | -0.43 | 0.06 | 0.79 | -0.61 |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of crop yields, the second principal component has a loading of -0.61 on yield.

    “| 2 | 0.67 | -0.25 | 0.54 | -0.43 | 0.06 | 0.79 | -0.61 |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of crop yields, the third principal component has a loading of 0.37 on application rate.

    “| 3 | 0.51 | 0.48 | -0.65 | -0.29 | 0.74 | 0.37 | 0.56 |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of crop yields, the third principal component has a loading of 0.74 on temperature.

    “| 3 | 0.51 | 0.48 | -0.65 | -0.29 | 0.74 | 0.37 | 0.56 |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of crop yields, the second principal component has a loading of 0.79 on application rate.

    “| 2 | 0.67 | -0.25 | 0.54 | -0.43 | 0.06 | 0.79 | -0.61 |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Findingown data
    § ACCEPTED MANUSCRIPT · p. 91

    In the PCA of crop yields, the third principal component has a loading of 0.56 on yield.

    “| 3 | 0.51 | 0.48 | -0.65 | -0.29 | 0.74 | 0.37 | 0.56 |”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Premisecitation
    § 46 ABSTRACT · p. 5

    Swine solids biochar is highest in Fe (74800 mg kg-1).

    “and Fe (74800 mg kg -1 ) contents.”
    • Also stated in: § ACCEPTED MANUSCRIPT · p. 14 · plain
      “Biochar prepared from swine solids contained 74800, 2240, 4981, 2446 and 27.4 mg kg -1 of Fe, Mn, Zn, Cu, and Mo, respectively (Table 1; Cantrell et al., 2012).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Cantrell et al., 2012 source

      Not checked in the free run.

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

    Premisenone given
    § 46 ABSTRACT · p. 5

    Swine solids biochar is highest in Zn (49810 mg kg-1).

    “swine solids biochar in Zn (49810 mg kg -1 )”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given
    § 74 1. Introduction · p. 7

    During pyrolysis, one-third to half of biomass carbon is converted into biochar.

    “During pyrolysis, one-third to half of biomass carbon is converted into biochar.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 8

    Biochar improves soil physical and biological properties.

    “It also provides other services such as improving soil physical and biological properties (Lehmann andRondon, 2005; Mandal et al., 2016a; Purakayastha et al., 2015; Purakayastha et al., 2016; Bera et al., 2016; Bera et al., 2019).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Lehmann andRondon, 2005

      Not checked in the free run.

    • cites Mandal et al., 2016a

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing). The quote only partly states this claim.

    Premisereasoning
    § ACCEPTED MANUSCRIPT · p. 14

    The N content in many biochar is less than 0.5%.

    “The very low N content (0.04%) in canola straw biochar conferred it the highest C/N ratio (160:1).”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given
    § 46 ABSTRACT · p. 5

    Poultry litter biochar is rich in P (3.12%).

    “Poultry litter biochar is a rich in P (3.12%)”
    Quote in the paperNot a substantial claim

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

    Premisereasoning
    § 74 1. Introduction · p. 7

    Biochar has a large surface area.

    “The heat treatment (more often thermochemical treatment) of organic biomass used to produce biochar contributes to its large surface area”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Lehmann et al., 2006 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S2 (checkable).

    Premisenone given
    § ACCEPTED MANUSCRIPT · p. 8

    Biochar application in soil for increasing crop production and other benefits including soil carbon sequestration is increasingly being recognized as a win-win strategy.

    “Biochar application in soil for increasing crop production and other benefits including soil carbon sequestration is increasingly being recognized as a win-win strategy.”
    Quote in the paperNot a substantial claim

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

    Premisenone given
    § 46 ABSTRACT · p. 5

    The N content in many biochar is more than 4%.

    “The N content in many biochar was reported to be more than 4%”
    • Also stated in: § ACCEPTED MANUSCRIPT · p. 14 · plain
      “Manure-derived biochar was undoubtedly the richest source of N among all feedstock types of biochar, showing N content as high as 4.45%.”
    Quote in the paperNot a substantial claim

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

    Premisecitation
    § 3. Role of biochar in mitigating climate change · p. 12

    The Paris Climate Agreement in 2015 set a target for participating countries to hold the increase in global average temperature to well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels.

    “the Paris Climate Agreement in 2015 set a target for participating countries that 'hold the increase in the global average temperature to well below 2°C above pre-industrial levels and to pursue efforts to limit the temperature increase to 1.5°C above pre-industrial levels' (IPCC 2015).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites IPCC 2015

      Not checked in the free run.

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

    Premisenone given
    § ACCEPTED MANUSCRIPT · p. 14

    The P content was lowest (0.017%) in yellow pine chip biochar.

    “while the lowest (0.017%) in yellow pine chip biochar.”
    Quote in the paperNot a substantial claim

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

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 14

    Biochar prepared from swine solids contained 74800 mg kg-1 Fe, 2240 mg kg-1 Mn, 4981 mg kg-1 Zn, 2446 mg kg-1 Cu, and 27.4 mg kg-1 Mo.

    “Biochar prepared from swine solids contained 74800, 2240, 4981, 2446 and 27.4 mg kg -1 of Fe, Mn, Zn, Cu, and Mo, respectively (Table 1; Cantrell et al., 2012).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Cantrell et al., 2012 source

      Not checked in the free run.

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

    Premisecitation
    § 3. Role of biochar in mitigating climate change · p. 12

    Simultaneous actions on negative emissions through sustainable carbon dioxide removal (CDR) technologies and engineered enhancement of natural carbon sinks are also urgently required.

    “simultaneous actions on negative emissions through sustainable carbon dioxide removal (CDR) technologies and engineered enhancement of natural carbon sinks are also urgently required (Gasser et al. 2015; Rogeljet al., 2016).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Gasser et al. 2015 source

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    • cites Rogeljet al., 2016

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  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given
    § ACCEPTED MANUSCRIPT · p. 14

    Data on micronutrient contents in biochar is limited in the literature.

    “Data on micronutrient contents in biochar is limited in the literature.”
    Quote in the paperNot a substantial claim

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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 13

    The global soil holds the largest terrestrial organic carbon pool (~1,500 Pg C to a depth of 1 m; 2,400 Pg C to 2 m depth).

    “The global soil has been estimated to hold the largest terrestrial organic carbon pool (~1,500 Pg C to a depth of 1 m; 2,400 Pg C to 2 m depth) (Batjes, 1996).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Batjes, 1996 source

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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 13

    An increase in organic matter inputs to soil, or a decrease in soil organic matter decomposition rates, or the net carbon gaining effect of both can increase the carbon stock in soil.

    “An increase in organic matter inputs to soil, or a decrease in soil organic matter decomposition rates, or the net carbon gaining effect of the both can increase the carbon stock in soil (Paustian et al., 2016).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Paustian et al., 2016 source

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

    Premisereasoning
    § ACCEPTED MANUSCRIPT · p. 14

    Waste material biochars had a wide range of C contents (19.2-84.0%).

    “Waste material biochars had a wide range of C contents (19.2-84.0%) indicating their differential initial constituents.”
    Quote in the paperNot a substantial claim

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

    Premisenone given
    § 4. Carbon and nutrient contents of biochar · p. 13

    The composition of biochar depends upon the nature of feedstock and pyrolysis conditions.

    “The composition of biochar depends upon the nature of feedstock and pyrolysis conditions”
    Quote in the paperNot a substantial claim

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

    Premisenone given
    § 3. Role of biochar in mitigating climate change · p. 12

    Conventional greenhouse gas emission mitigation strategies, such as lowering the consumption of fossil fuels, are needed to achieve the goal of the Paris Agreement.

    “While conventional greenhouse gas emission mitigation strategies, such as lowering the consumption of fossil fuels, are needed to achieve the goal of the Paris Agreement”
    Quote in the paperNot a substantial claim

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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 13

    The application of biochar to soils has been shown to achieve net carbon gain in soils while also serving for increased plant biomass production by enhancing the nutrient supply to plants and increasing nutrient and water use efficiencies (NUE and WUE) by plants.

    “In this connection, the application of biochar to soils has been shown to achieve the net carbon gain in soils while also serving for increased plant biomass production by enhancing the nutrient supply to plants and increasing nutrient and water use efficiencies (NUE and WUE) by plants (Kookana et al., 2011; Lehmann et al., 2015; Minasny et al., 2017).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Kookana et al., 2011 source

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    • cites Lehmann et al., 2015 source

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    • cites Minasny et al., 2017 source

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

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 14

    The P content was highest (5.90) in swine solid biochar.

    “The P content was recorded the highest (5.90) in swine solid biochar”
    Quote in the paperNot a substantial claim

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

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 13

    The '4 per mille Soils for Food Security and Climate' concept proposes to increase global soil organic matter stocks by 4 per 1000 (or 0.4%) per year in order to compensate global greenhouse gas emissions due to anthropogenic activities.

    “The recently launched '4 per mille Soils for Food Security and Climate' concept also proposes to increase global soil organic matter stocks by 4 per 1000 (or 0.4 %) per year in order to compensate global greenhouse gas emissions due to anthropogenic activities (Minasny et al., 2017).”
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    • cites Minasny et al., 2017 source

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  • May combine two claims.

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 14

    Paper mill biochar and poultry manure biochar prepared at 600°C were rich sources of Ca (25 and 31%, respectively) and Mg (0.87 and 0.29%, respectively).

    “The paper mill biochar (Devi and Saroha, 2015) and poultry manure biochar (Enders et al., 2012) prepared at 600 o C were reported to be rich sources of Ca (25 and 31%, respectively) and Mg (0.87 and 0.29%, respectively) (Table 1).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Devi and Saroha, 2015

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    • cites Enders et al., 2012 source

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

    Premisenone given
    § ACCEPTED MANUSCRIPT · p. 14

    The majority of biochar samples were alkaline in pH with few exceptions such as sugarcane bagasse biochar, yellow pine chip biochar, hazelnut biochar and eucalyptus biochar, which were found to be acidic in solution.

    “The majority of biochar samples were alkaline in pH with few exceptions such as sugarcane bagasse biochar, yellow pine chip biochar, hazelnut biochar and eucalyptus biochar, which were found to be acidic in solution.”
    Quote in the paperNot a substantial claim

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

    Premisereasoning
    § 4. Carbon and nutrient contents of biochar · p. 13

    Published literature suggests a wide variation in biochar compositions.

    “published literature suggests a wide variation in biochar compositions (Table 1).”
    Quote in the paperNot a substantial claim

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

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 13

    Biochar application to soils has been recommended as an important component of the pathway to 'climate-smart soil' management practices in modern global agriculture.

    “Thus, biochar application to soils has been recommended as an important component of the pathway to 'climate-smart soil' management practices in modern global agriculture (Paustian et al., 2016).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Paustian et al., 2016 source

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

    Premisereasoning
    § ACCEPTED MANUSCRIPT · p. 14

    The very low N content (0.04%) in canola straw biochar conferred it the highest C/N ratio (160:1).

    “The very low N content (0.04%) in canola straw biochar conferred it the highest C/N ratio (160:1).”
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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 15

    Increase in pyrolysis temperature from 400°C to 600°C significantly increased the C content, while it decreased the N content in all biochars except that produced from rice hull.

    “Purakayastha et al. (2016) reported that increase in pyrolysis temperature from 400 o C to 600 o C significantly increased the C content, while it decreased the N content in all biochars except that was produced from rice hull.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Purakayastha et al. (2016) source

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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 15

    Higher C contents were found in plant material based biochars, e.g., canola, soybean, peanut hull, pine chips, Eucalyptus saligna wood and leaf.

    “These findings were in agreement with the other studies which also found higher C contents in plant material based biochars, e.g., canola, soybean (Yuan et al., 2011), peanut hull, pine chips (Gaskin et al., 2008), Eucalyptus saligna wood and leaf (Singh et al., 2010).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Yuan et al., 2011

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    • cites Gaskin et al., 2008

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    • cites Singh et al., 2010 source

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  • May combine two claims.

    Premisecitation
    § 5.1.1. Biochar modifying soil physical environment · p. 16

    Incorporation of woody feedstock charcoals significantly decreased soil moisture retention at lower tensions (10 and 30 kPa), resulting in an increase in relative hydraulic conductivity at these tensions in a clay soil.

    “Bayabil et al. (2015) reported that incorporation of woody feedstock (Acacia, Croton, and Eucalyptus) charcoals significantly decreased the soil moisture retention at lower tensions (10 and 30 kPa), resulting in an increase in relative hydraulic conductivity at these tensions in a clay soil.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Bayabil et al., 2015 source

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  • May combine two claims.

    Interpretationreasoning
    § 5.1.2. Biochar modifying soil pH, buffering system, CEC · p. 17

    Biochar may alter soil pH, which in turn can change nutrient solubility, thereby modifying nutrient availability.

    “Biochar may alter soil pH, which in turn can change nutrient solubility, thereby modifying the nutrient availability.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Soil nutrient availability for plants is pH dependent.

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

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 15

    The C/N ratio of switch grass biochar increased from 54 to 84 when pyrolysis temperature increased from 400°C to 600°C.

    “For example, the C/N ratio of switch grass biochar increased from 54 to 84 when pyrolysis temperature increased from 400 o C to 600 o C (Purakayastha et al., 2016).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Purakayastha et al., 2016 source

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  • May combine two claims.

    Interpretationcitation
    § ACCEPTED MANUSCRIPT · p. 19

    The liming effect of biochar in acid soils could improve mineral nutrient supply for plant growth and alleviate Al stress for better crop production.

    “The liming effect of biochar in acid soils, as described above, not only could improve the mineral nutrient supply for plant growth, but also could alleviate Al stress for better crop production (Liu et al. 2013; Dai et al., 2017).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Liu et al. 2013 source

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    • cites Dai et al., 2017 source

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

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 15

    The C content decreased in corn and peanut biochar with an increasing pyrolysis temperature from 300°C to 500°C.

    “Contrastingly, Yuan et al. (2011) reported that the C content decreased in corn and peanut biochar with an increasing pyrolysis temperature from 300 o C to 500 o C.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Yuan et al. (2011)

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    Interpretationreasoning
    § ACCEPTED MANUSCRIPT · p. 18

    Alfisols, Ferrosols and Acrisols are inherently highly acidic, and biochar being alkaline material neutralised the acidity.

    “Alfisols, Ferrosols and Acrisols are inherently highly acidic in nature, and biochar being alkaline material neutralised the acidity.”
    Quote in the paperSubstantial claim
    • Rests on an assumption: Biochar is an alkaline material.

  • May combine two claims.

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 17

    Wood chip biochar and waste-water sludge biochar were more efficient in increasing the porosities of the products over straw biochar, and showed greater effects on soil macroaggregates.

    “The authors also reported that wood chip biochar and waste-water sludge biochar were more efficient in increasing the porosities of the products over straw biochar, and hence showed greater effects on soil macroaggregates (Yu et al., 2016).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Yu et al., 2016

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

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 15

    The C/N of sugarcane bagasse biochar decreased from 129 to 79 when pyrolysis temperature increased from 250°C to 500°C.

    “In contrast, Novak et al. (2009) reported that the C/N of sugarcane bagasse biochar decreased from 129 to 79 when pyrolysis temperature increased from 250 o C to 500 o C.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Novak et al. (2009) source

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  • May combine two claims.

    Premisecitation
    § 5.1.1. Biochar modifying soil physical environment · p. 16

    Biochar amendments improve soil bulk density, porosity, water retention, and hydraulic conductivity.

    “Biochar amendments were reported to improve soil bulk density, porosity, water retention, and hydraulic conductivity (Abel et al., 2013; Asai et al., 2009; Atkinson et al., 2010; Jeffery et al., 2011; Karhu et al., 2011; Laird et al., 2010a).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Abel et al., 2013 source

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    • cites Asai et al., 2009 source

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    • cites Atkinson et al., 2010 source

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  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Premisenone given
    § ACCEPTED MANUSCRIPT · p. 15

    The slow and fast pyrolysis process during heating could also influence the C and N contents, and C/N ratios.

    “The slow and fast pyrolysis process during heating could also influence the C and N contents, and C/N ratios.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation
    § 5.2.1. Effect of biochar on nitrogen dynamics · p. 22

    Maize biochar accelerates soil N transformations by increasing net N mineralization, accelerating nitrification, affecting denitrification, reducing ammonia volatilization, and through adsorption of ammonia and increasing NH4+ storage in soils.

    “Thus, maize biochar was reported to accelerate soil N transformations by increasing the net N mineralization (Nelissen et al., 2012, Gundale and DeLuca, 2006), accelerating nitrification (Song et al., 2013), affecting denitrification (Cayuela et al., 2013), reducing ammonia volatilization (Mandal et al., 2016b; 2018), and through adsorption of ammonia”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Nelissen et al., 2012

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    • cites Gundale and DeLuca, 2006

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    • cites Song et al., 2013

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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 21

    The impact of peanut hull biochar was more pronounced than pine chip biochar due to the higher contents of K, Ca and Mg in the former, and in the first year of biochar application than the second year.

    “The impact of peanut hull biochar was more pronounced than pine chip biochar due to the higher contents of K, Ca and Mg in the former, and in the first year of biochar application than the second year (Gaskin et al., 2010).”
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    • cites Gaskin et al., 2010 source

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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 24

    PyOM derived from rye grass pyrolyzed at 450°C induced a strongly positive priming effect within the first 18 days, and thereafter a negative priming effect in a forest Cambisol.

    “For instance, PyOM derived from rye grass pyrolyzed at 450 o C induced a strongly positive priming effect within the first 18 days, and thereafter exhibiting a negative priming effect in a forest Cambisol (Maestrini et al., 2014).”
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    • cites Maestrini et al., 2014 source

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  • May combine two claims.

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 24

    Compared to unamended soil, amendment with biochar produced at 200°C and 400°C from oak wood significantly increased N2O emissions, but biochar produced at 600°C did not show such effect on N2O emissions.

    “Compared to the unamended soil, amendment with biochar (produced at 200 o C and 400 o C from oak wood feedstock) significantly increased N2O emissions, but biochar produced at a higher temperature (600 o C) did not show such effect on N2O emissions (Zhang et al., 2015).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Zhang et al., 2015 source

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

    Interpretationreasoning
    § ACCEPTED MANUSCRIPT · p. 22

    These are all indirect evidences of enriched nutrient availabilities resulted from biochar addition to soils.

    “These are all indirect evidences of enriched nutrient availabilities resulted from biochar addition to soils.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 24

    During pyrolysis, N in biomasses get converted to recalcitrant heterocyclic aromatic structures in biochar, and these structural changes may lead to a reduction in C and N mineralization rates.

    “During the pyrolysis process, N in biomasses get converted to recalcitrant heterocyclic aromatic structures in biochar, and these structural changes may lead to a reduction in C and N mineralization rates (Chen et al., 2014).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Chen et al., 2014 source

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    Interpretationcitation
    § ACCEPTED MANUSCRIPT · p. 24

    The C stability of leguminous green manure like Ipomoea sp. could be enhanced by converting the raw material into biochar, but the charring process might limit the immediate supply of N.

    “Therefore, the C stability of leguminous green manure like Ipomoea sp. could be enhanced by converting the raw material into biochar, but the charring process might limit the immediate supply of N.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation
    § ACCEPTED MANUSCRIPT · p. 23

    Biochar induced increase of soil porosity/aeration stimulates the aerobic/heterotrophic microbial population resulting in degradation of recalcitrant SOM in the presence of biochar.

    “This could be due to the biochar induced incresae of soil porosity/aeration that stimulates the aerobic/heterotrophic microbial population resulting in the degradation of recalcitrant SOM in the presence of biochar (Anderson et al., 2011).”
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    • cites Anderson et al., 2011 source

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  • May combine two claims.

    Interpretationcitation
    § ACCEPTED MANUSCRIPT · p. 23

    PyOM produced at a low temperature could be easily degraded, and its N would become available to plants.

    “This showed a direct evidence that PyOM produced at a low temperature could be easily degraded, and its N would become available to plants (Rosa and Knicker, 2011).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Rosa and Knicker, 2011

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  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationreasoning
    § ACCEPTED MANUSCRIPT · p. 20

    Increase in CEC could affect the retention of phosphate by biochar through anion exchange reaction.

    “The increase in CEC could affect the retention of phosphate by biochar through anion exchange reaction.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 24

    Other important mechanisms include an enhanced abundance of ammonia oxidizing microorganisms, and promotion of denitrification by the transfer of electrons to soil denitrifying microbes.

    “The other important mechanisms include an enhanced abundance of ammonia oxidizing microorganisms (Song et al., 2013), and promotion of denitrification by the transfer of electrons to soil denitrifying microbes (Cayuela et al., 2013).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Song et al., 2013

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    • cites Cayuela et al., 2013

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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 24

    Soil amended with biochar produced at temperatures exceeding 400°C demonstrated a 25% decrease in dry shoot biomass of water spinach compared with unamended soil principally due to N limitation.

    “As such, soil amended with biochar produced at temperatures exceeding 400°C demonstrated a 25% decrease in dry shoot biomass of water soinach ( Ipomoea aquatica ) compared with unamended soil principally due to N limitation (Chen et al., 2014).”
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    • cites Chen et al., 2014 source

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  • May combine two claims.

    Premisecitation
    § 5.2.1. Effect of biochar on nitrogen dynamics · p. 22

    Biochar being rich in surface functional groups, including aromatic moieties, can alter cation and anion exchange capacities of soils, which further influences N retention.

    “Biochar being rich in surface functional groups, including aromatic moieties, can alter cation and anion exchange capacities of soils, which further influences N retention (Clough et al., 2013; Slavich et al., 2013; Mandal et al., 2018).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Clough et al., 2013 source

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    • cites Slavich et al., 2013 source

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    • cites Mandal et al., 2018 source

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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 23

    Most mineralized NH4+ under biochar treatments came from recalcitrant N in soil, while in control soil most mineralized NH4+ originated from labile N.

    “Most of the mineralized NH4 + under biochar treatments came from the recalcitrant N in soil, while in the control soil most mineralized NH4 + originated from the labile N (Nelissen et al., 2012).”
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    • cites Nelissen et al., 2012

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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 23

    Biochar addition accelerated soil N cycling with increased gross N mineralization (185-221%), nitrification (10-69%) and ammonium consumption rates (333-508%).

    “Results showed accelerated soil N cycling following biochar addition, with increased gross N mineralization (185-221%), nitrification (10-69%) and ammonium (NH4 + ) consumption rates (333-508%) (Nelissen et al., 2012).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Nelissen et al., 2012

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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 26

    Adsorbed NH4+-N eventually become available to plants or microbes in the long run reducing the loss of mineral N in soils.

    “The adsorbed NH 4 + -N eventually become available to plants or microbes in the long run reducing the loss of mineral N in soils (Taghizadeh-Toosi et al., 2012a, 2012b).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Taghizadeh-Toosi et al., 2012a

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    • cites Taghizadeh-Toosi et al., 2012b

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  • May combine two claims.

    Premisecitation
    § 5.2.3. Effect of biochar on phosphorus dynamics · p. 28

    Zhang et al. (2016) studied biochars from 9 different residues, and concluded that Bladygrass biochar had the greatest amount of extractable P among all the biochars.

    “For example, Zhang et al. (2016) studied biochars prepared from 9 different residues, and concluded that the Bladygrass ( Imperata cylindrical ) biochar had the greatest amount of extractable P among all the biochars.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Zhang et al., 2016

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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 25

    Soil and biochar mixtures showed evidence of both soil nutrient sorption by biochar, and biochar nutrient sorption by the soil, depending upon the biochar and soil types.

    “Soil and biochar mixtures showed evidence of both soil nutrient sorption by biochar, and biochar nutrient sorption by the soil, depending upon the biochar and soil types (Mukherjee and Zimmerman, 2013; Rens et al., 2018).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Mukherjee and Zimmerman, 2013

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    • cites Rens et al., 2018 source

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    Interpretationcitation
    § 5.2.3. Effect of biochar on phosphorus dynamics · p. 28

    Extractable P not only depends on pyrolysis temperature, but also on feedstock.

    “The extractable P not only depends on the pyrolysis temperature, but also on the feedstock.”
    Quote in the paperNot a substantial claim

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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 28

    The primary reason for higher BNF with biochar additions was greater B and Mo availability in the amended soil than the unamended control, while greater K, Ca, and P availability with higher soil pH and lower N availability and Al saturation might have also concurrently occurred.

    “The primary reason for the higher BNF with biochar additions was the greater B and Mo availability in the amended soil than the unamended control, while a greater K, Ca, and P availability with higher soil pH and lower N availability and Al saturation might have also concurrently occurred (Rondon et al., 2007).”
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    • cites Rondon et al., 2007 source

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

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 26

    NH4+ adsorption capacities of commercial coconut shell activated carbon prepared at 600°C and 400°C were 2400 and 600 to 1800 mg NH3 kg-1 carbon, respectively.

    “The NH4 + adsorption capacities of commercial coconut shell activated carbon prepared at 600 o C and 400 o C were found to be 2400 and 600 to 1800 mg NH3 kg -1 carbon, respectively (Rodrigues et al., 2007).”
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    • cites Rodrigues et al., 2007 source

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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 27

    Available N content increased in an alkaline sandy loam soil under the influence of biochar, and the effect was more pronounced for maize stover than wheat straw biochar.

    “The available N content increased in an alkaline sandy loam soil too under the influence of biochar, and the effect was more pronounced for maize stover than wheat straw biochar (Purakayastha et al., 2015).”
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    • cites Purakayastha et al., 2015 source

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

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 26

    Biochar application to soil with urea increased NH3 volatilization losses by 14.1% in the first rice season, primarily due to increased pH and concentrations of NH4+-N in the floodwater, and decreased NH3 losses in the second rice growth season by 6.8%, probably due to its high adsorption capacity for NH4+ and increased nitrification.

    “Recently Hea et al. (2018) reported that biochar application to soil with urea increased NH3 volatilization losses by 14.1% in the first rice season, primarily due to increased pH and concentrations of NH4 + -N in the floodwater, and decreased NH3 losses in the second rice growth season by 6.8%, probably due to its high adsorption capacity for NH4 + and increased nitrification.”
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    • cites Hea et al., 2018 source

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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 27

    Biochar addition showed limited effects on the turnover of soil organic carbon, DON and no long-term effect on N mineralization, NH3 volatilization, denitrification and NH4 sorption.

    “Similarly, biochar addition showed limited effects on the turnover of soil organic carbon, DON and no long-term effect on N mineralization, NH3 volatilization, denitrification and NH4 sorption (Clough et al., 2013).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Clough et al., 2013 source

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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 26

    Yao et al. (2012) reported that sugarcane bagasse, peanut hull, Brazilian pepperwood, and bamboo biochars could adsorb 112% NH4+-N from aqueous solution, and Brazilian pepperwood gave the most effective biochar for NH4+ adsorption among these feedstocks.

    “Yao et al. (2012) reported that sugarcane bagasse, peanut hull, Brazilian pepperwood, and bamboo biochars could adsorb 112% NH4 + -N from aqueous solution, and Brazilian pepperwood gave the most effective biochar for NH4 + adsorption among these feedstocks.”
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    § ACCEPTED MANUSCRIPT · p. 31

    Poultry litter and wheat straw biochars applied at 5 and 10 Mg ha−1 did not affect Olsen's P in an acidic Ferrasol and alkaline Calcisol, but could increase Olsen's P in an acidic aerosol and neutral Vertisol.

    “However, Macdonald et al. (2014) reported that both poultry litter and wheat straw biochars applied at the rate of 5 and 10 Mg ha -1 did not affect the Olsen's P in an acidic Ferrasol and alkaline Calcisol, but could increase Olsen's P in an acidic aerosol and neutral Vertisol.”
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    § ACCEPTED MANUSCRIPT · p. 32

    Biochar itself is a huge source of K and can directly take part in retention of K in soil because of its high CEC.

    “Biochar itself is a huge source of K, and it can directly take part in the retention of K in the soil because of having a high CEC (Table 3).”
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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 30

    At higher biochar application rates, P concentrations decreased, coinciding with an increase of soil pH by 0.3-0.7 units.

    “At higher application rates, P concentrations decreased, which coincided with an increase of soil pH by 0.3-0.7 units (Parvage et al., 2013).”
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    § ACCEPTED MANUSCRIPT · p. 30

    Biochar's effect on both soil Olsen-P and microbial biomass-P was increased by higher biochar application rates, ensuring lower P-sorption capacity.

    “Biochar's effect on both soil Olsen-P and microbial biomass-P was increased by higher biochar application rates ensuring lower P-sorption capacity.”
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    § ACCEPTED MANUSCRIPT · p. 29

    Biochar having high ion exchange capacity might alter P availability by enhancing the anion exchange capacity or by influencing the activity of cations that interact with P.

    “Biochar having high ion exchange capacity might alter P availability by enhancing the anion exchange capacity or by influencing the activity of cations that interact with P (Liang et al., 2006).”
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    § ACCEPTED MANUSCRIPT · p. 31

    Rice straw biochar with higher CEC and lowest contents of Ca2+ and Mg2+ showed the greatest inhibition of phosphate adsorption, and thus could likely be the best choice as an amendment to mobilize phosphate in variably-charged soils.

    “Rice straw biochar with the higher CEC and the lowest contents of Ca 2+ and Mg 2+ showed the greatest inhibition of phosphate adsorption, and thus, could likely be the best choice as an amendment to mobilize phosphate in variably-charged soils (Jiang et al., 2015).”
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    § ACCEPTED MANUSCRIPT · p. 31

    Incorporation of biochars increased the pH of amended soils, thereby further mobilizing phosphate in the soil.

    “Incorporation of the biochars increased the pH of the amended soils, thereby further mobilizing phosphate in the soil (Jiang et al., 2015).”
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    § ACCEPTED MANUSCRIPT · p. 30

    Addition of fresh Miscanthus or Salix biochar to soil significantly increased soil P contents, but artificially weathered biochars made no such change in a sandy loam soil at Rothamsted Research experimental farm, UK.

    “The addition of fresh Miscanthus or Salix biochar to soil significantly increased soil P contents, but artificially weathered biochars made no such change in sandy loam soil of the Rothamsted Research experimental farm, United Kingdom (Prendergast-Miller et al., 2014).”
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    § ACCEPTED MANUSCRIPT · p. 31

    In sandy soil, addition of biochar produced from a mixture of Norway spruce and Scots pine had low P sorption affinity and did not increase P sorption in incubated soils.

    “In sandy soil, addition of biochar produced from mixture of Norway spruce ( Picea abies (L.) H. Karst) and Scots pine ( Pinus sylvestris L.) had low P sorption affinity, and thus did not increase the sorption of P in incubated soils (Sonnie et al., 2014).”
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    § ACCEPTED MANUSCRIPT · p. 30

    The same 8% maize stover biochar application increased soil microbial biomass P from 1 to 9 mg kg−1 in the Red earth and from 9 to 21 mg kg−1 in the Fluvo-aquic soil.

    “These increases were accompnied with an subsequent increase in soil microbial biomass P from 1 to 9 mg kg -1 in the Red earth, and from 9 to 21 mg kg -1 in the Fluvoaquic soil (Zhai et al., 2015).”
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    § ACCEPTED MANUSCRIPT · p. 30

    The maximum concentration of water-soluble P was achieved at 1% wheat residue biochar (w/w) addition to soils of different textural classes, with water-soluble P concentrations varying from 11 to 253%.

    “The maximum concentration of water-soluble P was achieved at the rate of 1% wheat residue biochar (w/w) addition to soils with different textural classes, varying the water-soluble P concentrations from 11 to 253% (Parvage et al., 2013).”
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    § ACCEPTED MANUSCRIPT · p. 29

    Haefelea et al. (2011) reported that the application of carbonized rice husk biochar increased available P in rice growing soil of IRRI, Philippines, in the first year, while after three years it did not influence the available P content.

    “Haefelea et al. (2011) reported that the application of carbonized rice husk biochar increased available P in rice growing soil of International Rice Research Institute (IRRI), Philippines, in the first year, while after three years it did not influence the available P content.”
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    Interpretationreasoning
    § ACCEPTED MANUSCRIPT · p. 29

    Increased soil microbial activity and reduced soil acidity or increased CEC may account for enhanced P transformation in the soil.

    “The increased soil microbial activity and reduced soil acidity or increased CEC may be accounted for enhanced P transformation in the soil.”
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    Interpretationreasoning
    § ACCEPTED MANUSCRIPT · p. 30

    Wheat residue biochar can act as a source of soluble P, and low and high additions of biochar have different effects on soil solution P concentration due to possible reactions of P with Ca and Mg added with biochar.

    “The wheat residue biochar can act as a source of soluble P, and low and high additions of biochar showed different effects on soil solution P concentration due to possible reactions of P with Ca and Mg added with biochar.”
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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 37

    The lowest N-leaching-loss was observed with BSRFs, attributed to BSRFs having better slow-release characteristics and water holding capacity than normal biochar.

    “The lowest N-leaching-loss were observed with BSRFs, and the phenomenon was attributed to the fact that BSRFs had better slow-release characteristics and water holding capacity than normal biochar (Gonzalez et al., 2015; Wen et al., 2017).”
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    • cites Wen et al., 2017 source

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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 34

    Biochar prepared from Eucalyptus tree either via traditional kiln at 350°C or flash carbonization at 800°C significantly increased soluble Mn concentration (1.39-4.61 mg L−1) in an Oxisol relative to control (1.12 mg L−1), while decreasing plant tissue Mn concentration (0.08-0.17 g kg−1) compared to control (0.41 g kg−1).

    “Biochar prepared from Eucalyptus tree either via traditional kiln process at 350°C or by flash carbonization at 800°C significantly increased the soluble Mn concentration (1.39-4.61 mg L -1 ) in an Oxisol relative to the control (1.12 mg L -1 ), while they decreased the plant tissue Mn concentration (0.08-0.17 g kg -1 ) compared to the control (0.41 g kg -1 ) (Butnan et al., 2015).”
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    Interpretationcitation
    § 7. Biochar as slow release fertilizer · p. 36

    Pyrolytic conversion of biomass into biochar has shown an effective impact on reducing nutrient losses (NH3 volatilization, N2O emission, CO2 emission, NO3 leaching, etc.) from soils, and biochar itself contains nutrients that help improve plant growth.

    “Pyrolytic conversion of biomass into biochar has shown an effective impact on reducing nutrient losses (NH3 volatilization, N2O emission, CO2 emission, NO3 leaching, etc.) from soils, and previous studies found that biochar itself contains nutrients, which help to improve plant growth.”
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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 38

    Some biochars triggered improved growth with increasing pyrolysis temperatures, though the opposite trend was also found.

    “Some biochars triggered improved growth with increasing pyrolysis temperatures, though opposite trend was also found (Rajkovich et al., 2012).”
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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 38

    Except for the larger application rate (7%), biochar made from corn stover, oak, and pine wood and animal manures exhibited either positive or neutral effect on crop growth, whereas biochar from hazelnut shells did not affect growth.

    “Except for the larger application rate (7%), biochar made from corn stover, oak, and pine wood and animal manures exhibited either positive or neutral effect on crop growth, whereas biochar from hazelnut shells did not affect the growth (Enders et al., 2012).”
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    § ACCEPTED MANUSCRIPT · p. 39

    Total biomass of spring barley was increased by 11% due to biochar application, though with a non-significant response for grain yield.

    “However, on the same occasion, the total biomass of spring barley ( Hordeum vulgare ) was increased by 11% due to biochar application, though with a non-significant response for grain yield.”
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    • cites Sun et al., 2014 source

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    § ACCEPTED MANUSCRIPT · p. 37

    Phosphate-laden biochar contained valuable nutrients that could act as a slow release fertilizer to enhance soil fertility and sequester C for a longer time in soil.

    “Yao et al. (2011) also found that the phosphate-laden biochar contained valuable nutrients that could act as a slow release fertilizer to enhance soil fertility and sequester C for a longer time in soil.”
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    Premisecitation
    § 7. Biochar as slow release fertilizer · p. 36

    Lignocellulosic biomass-derived biochar contained low plant nutrients but could be impregnated with additional nutrients and subsequently pelletized, and the final product could control the release of nutrients at a slower rate resulting in reduced nutrient loss.

    “Kim et al. (2014) observed that lignocellulosic biomass-derived biochar contained low plant nutrients but could be impregnated with additional nutrients and subsequently pelletized, and the final product could control the release of nutrients at a slower rate resulting in a reduced nutrient loss.”
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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 34

    Soil extractable Mn and Fe decreased, while Cu and Zn increased due to application of a mixed wood biochar.

    “Among the micronutrients, soil extractable Mn and Fe decreased, while Cu and Zn increased due to the application of a mixed wood biochar (Rogovska et al., 2014).”
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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 34

    Composted charcoal could potentially improve plant available Cu2+ in an acidic sandy soil with small organic matter content.

    “Similarly, Borchard et al. (2012) reported that composted charcoal could potentially improve plant available Cu 2+ in an acidic sandy soil with small organic matter content.”
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    § ACCEPTED MANUSCRIPT · p. 38

    Across all biochar types, average total biomass production of corn was at par for application rates of 0.2%, 0.5%, and 2%, but reduced to a minimum at 7%.

    “Across all biochar types, average total biomass production of corn ( Zea mays L.) was at par for the application rates of 0.2%, 0.5%, and 2%, but reduced to a minimum at the rate of 7% (Rajkovich et al., 2012).”
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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 38

    Crop choices also can determine the response of biochar, as wheat biomass increased linearly up to biochar application rate of 10 t ha−1 and decreased with 20 and 50 t ha−1, whereas radish growth did not decrease with high rate of biochar in an acid soil of the tropics.

    “However, not only the biochar or soil type, crop choices also can determine the response of biochar as van Zwieten et al. (2010) found that wheat biomass increased linearly up to an biochar application rate of 10 t ha -1 , and decreased with 20 and 50 t ha -1 , whereas radish growth did not decrease with high rate of biochar in an acid soil of the tropics.”
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    § ACCEPTED MANUSCRIPT · p. 34

    Slow pyrolysis biochar (550°C) failed to show any effect on exchangeable Ca content after harvest of a maize crop when applied at 15.0 g kg−1 in a silty Fluvisol, but became more efficient when application rate was increased to 100 g kg−1.

    “Slow pyrolysis biochar (550 o C) failed to show any effect on exchangeable Ca content after harvest of a maize crop when applied at the rate of 15.0 g kg -1 in a silty Fluvisol, but it became more efficient when the application rate was increased to 100 g kg -1 (Borchard et al., 2014).”
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    § ACCEPTED MANUSCRIPT · p. 37

    BSRFs were capable of releasing N fertilizer slowly with extended N-longevity, and were more effective in improving total N use efficiency and facilitated cotton plant growth through reducing N loss and improving N retention.

    “The BSRFs were also capable of releasing N fertilizer slowly with extended N-longevity, and were more effective in improving total N use efficiency and facilitated cotton plant growth through reducing N loss and improving N retention (Wen et al., 2017).”
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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 33

    Peanut straw biochar pyrolyzed at 400°C showed significantly higher water soluble Ca and Mg contents in an Oxisol than other straw-derived biochars, and rice straw biochar showed the lowest values among various crop straw biochars.

    “Peanut straw biochar pyrolyzed at 400 o C showed significantly higher water soluble Ca and Mg contents in an Oxisol than other starw derived biochars, and rice straw biochar showed the lowest values among various crop straw biochars (Jiang et al., 2015).”
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    § ACCEPTED MANUSCRIPT · p. 34

    After biochar application, Ca and Mg limiting Savana Oxisol was highly productive due to 77-320% greater Ca and Mg availability, increasing soil pH and decreasing exchangeable acidity.

    “After biochar application, Ca and Mg limiting Savana Oxisol was higly productive due to 77-320% greater Ca and Mg availability, increasing soil pH and decreasing exchangable acidity (Major et al., 2010).”
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    Interpretationreasoning
    § ACCEPTED MANUSCRIPT · p. 37

    Biochar based slow-release fertilizers with effective nutrient retention properties can be widely used in sustainable modern agriculture.

    “Studies have shown that biochar based slow-release fertilizers with their effective nutrient retention properties can be widely used in sustainable modern agriculture.”
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    Premisecitation
    § 6. Pyrolysis conditions, stability and nutrient supplying capacity of biochar · p. 35

    Pyrolysis temperature was found to be the most influential parameter for obtaining specific characteristics of rapeseed stem biochar, showing a positive relationship with pH, microporous structure, surface area, fixed C and ash content, and a negative relationship with material yield, average pore size, functional groups, volatile matter, O and H mass fractions, and number and density of функцій.

    “Pyrolysis temperature was also found to be the most influential parameter for obtaining specific characteristics of rapeseed stem biochar, demonstrating a positive relationship of temperature with pH, microporous structure, surface area, fixed C and ash content, whilst showing a negative relationship with material yield, average pore size, functional groups, volatile matter, O”
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    • cites Zhao et al., 2018 source

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    § ACCEPTED MANUSCRIPT · p. 40

    Peanut hull biochar and pine chip biochar failed to show marks towards crop productivity, and grain yield even decreased for maize crop.

    “However, Gaskin et al., (2009) found that peanut hull biochar and pine chip biochar failed to show their marks towards crop productivity, and grain yield even decreased for maize crop.”
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    § ACCEPTED MANUSCRIPT · p. 40

    Application of 0, 8 and 20 t ha−1 of biochar to a Colombian savanna Oxisol continuously for four years (2003-2006) under a maize-soybean rotation resulted in no increase in maize grain yield in the first year, but increased in the 20 Mg ha−1 plots over control by 28, 30 and 140%, respectively, in subsequent years.

    “Application of 0, 8 and 20 t ha -1 of biochar to a Colombian savanna Oxisol continuously for four years (2003-2006) under a maize-soybean rotation reported that the maize grain yield did not increase in the very first year, but increased in the 20 Mg ha -1 plots over the control by 28, 30 and 140%, respectively, in the subsequent years (Major et al., 2010).”
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    § ACCEPTED MANUSCRIPT · p. 41

    Applying N fertilizer proved beneficial to rice grain yield when 4.0 and 8.0 Mg ha−1 rates of two commercial biochars prepared from wood feedstocks were applied in northern Laos, but at higher dose of biochar (16 Mg ha−1) with N-fertilizer no positive yield response was observed.

    “Similarly, applying N fertilizer proved beneficial to rice grain yield when 4.0 and 8.0 Mg ha -1 rates of two commercial biochars prepared from wood feedstocks (e.g., teak ( Tectona grandis L.) and rosewood ( Pterocarpus macrocarpus Kurz)) were applied in a study reported from northern Laos, but at higher dose of biochar (16 Mg ha -1 ) with N-fertilizer no positive”
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    § ACCEPTED MANUSCRIPT · p. 43

    No difference between the two biochar treatments were identified, suggesting that even the very high biochar application rate promoted plant growth with a non-detrimental effect.

    “Moreover, no difference between the two biochar treatments were identified, suggesting that even the very high biochar application rate promoted plant growth with a non-detrimental effect (Vaccari et al., 2011).”
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    • cites Vaccari et al., 2011 source

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    § ACCEPTED MANUSCRIPT · p. 43

    In contrast to biochar amendment, N fertilizer proved less effective for improving soil quality, but more effective for increasing rice yield.

    “In contrast to biochar amendment, N fertilizer proved less effective for improving soil quality, but more effective for increasing the rice yield (Huang et al., 2013).”
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    § ACCEPTED MANUSCRIPT · p. 43

    Large volume application of biochar (30 and 60 Mg ha−1) on durum wheat in the Mediterranean climate showed positive effects (up to 30%) on biomass production and yield, with no significant differences in the nitrogen content of grains.

    “Another investigation dealing with large volume application of biochar (30 and 60 Mg ha -1 ) on durum wheat in the Mediterranean climate showed positive effects (up to 30%) on biomass production and yield, with no significant differences in the nitrogen content of grains (Vaccari et al., 2011).”
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    § ACCEPTED MANUSCRIPT · p. 42

    Zhang et al. (2012) found maize yield increased by 15.8% and 7.3% without N fertilization, and by 8.8% and 12.1% with N fertilization under biochar amendment at 20 and 40 Mg ha−1, respectively, in a calcareous flavor-aquic loamy soil.

    “Contrary to this observation, Zhang et al., (2012) found maize yield increased by 15.8% and 7.3% without N fertilization, and by 8.8% and 12.1% with N fertilization under biochar amendment at 20 and 40 Mg ha -1 , respectively, in a calcareous flavor-aquic loamy soil.”
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    § ACCEPTED MANUSCRIPT · p. 42

    Application of biochar prepared from a weed (Parthenium hysterophorus L.) at 370-417°C to a rice-wheat cropping system could cut down the cost of fertilizer to half although the yield obtained was just as good as with full application of recommended dose of fertilizers.

    “Recently, Ain et al. (2016) reported that application of biochar prepared from a weed ( Parthenium hysterophorus L.) at 370- 417 o C temperature to a rice-wheat cropping system could cut down the cost of fertilizer to half although the yield obtained was just as good as with full application of recommended dose of fertilizers.”
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    § ACCEPTED MANUSCRIPT · p. 41

    Application of biochar poultry manure compost and pyroligneous solution to a salt-affected soil for consecutive two years showed an ameliorative effect, decreasing salinity and pH, and subsequently reflected in increased yield of wheat by 38%.

    “Application of biochar poultry manure compost and pyroligneous solution to a salt-affected soil for consecutive two years showed an ameliorative effect, decreasing the salinity and pH, and subsequently reflected in increased yield of wheat in a tune of 38% (Lashari et al., 2013).”
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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 40

    This treatment was found to be superior for obtaining benefits related to straw reutilization like crop residue incorporation (CRI) and crop residue burning (CRB) in the open field.

    “Moreover, this treatment was found to be superior for obtaining benefits related to straw reutilization like crop residue incorporation (CRI) and crop residue burning (CRB) in the open field.”
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    Interpretationcitation
    § ACCEPTED MANUSCRIPT · p. 42

    Improvement in soil physical properties along with pH, organic carbon and content of exchangeable cations were the reasons suggested for the higher radish yield.

    “Improvement in soil physical properties along with pH, organic carbon and content of exchangeable cations were the reasons suggested for the higher radish yield.”
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    § ACCEPTED MANUSCRIPT · p. 40

    Application of rice straw biochar (prepared at 400°C) at 2.25 g kg−1 (equivalent to 5.0 t ha−1) along with 100% NPK increased rice yield by 24.3% in an Inceptisol and by 31.3% in an Alfisol.

    “In another study, the application of rice straw biochar (prepared at 400 °C) at the rate of 2.25 g kg -1 (equivalent to 5.0 t ha -1 ) along with 100% NPK increased the rice yield by 24.3% in an Inceptisol, and by 31.3% in an Alfisol (Bera, 2014).”
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    § ACCEPTED MANUSCRIPT · p. 42

    The bioavailability of N in a wheat-straw biochar prepared at 400°C was very low, and did not increase growth of rice crop or nitrogen use efficiency from fertilizer sources during the first year after application.

    “The bioavailability of N in a wheat-straw biochar prepared at 400 o C was reported to be very low, and did not increase growth of rice crop or nitrogen use efficiency from fertilizer sources during the first year after application (Xie et al., 2013).”
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    § ACCEPTED MANUSCRIPT · p. 43

    Biochar additions significantly increased total biomass production by 39% at a defined biochar dose of 60 g kg−1, but decreased biomass at par with the control with a higher biochar dose (90 g kg−1).

    “Biochar additions significantly increased total biomass production by 39% at a defined biochar dose of 60 g kg -1 , but decreased biomass at par with the control with a higher biochar dose (90 g kg -1 ).”
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    • cites Güereña et al., 2015 source

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    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 42

    Biochar added to an agricultural field at 0, 25 and 50 t ha−1 and planted with maize (1st year) and grass (2nd and 3rd years) in an acidic sandy loam soil affected plant performance in the grass crop with significant increase in foliar N (2nd year) and aboveground biomass (3rd year), but behaved neutral towards maize crop yield.

    “Biochar was added to an agricultural field at three different doses (0, 25 and 50 t ha -1 ) and planted with maize (1 st year) and grass (2 nd and 3 rd years) in an acidic sandy loam soil where the biochar addition affected plant performance in the grass crop with significant increase in foliar N (2 nd year) and aboveground biomass (3 rd year), but biochar treatment behaved neutral”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Jones et al., 2012 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 41

    Rice yield was increased under biochar treatment in an acidic Anthrosol, and such increase was more (9-28%) in the second cycle than in the first cycle (9-12%).

    “Rice yield was increased under biochar treatment in an acidic Anthrosol, and such increase was eventually more (9-28%) in the second cycle than in the first cycle (9-12%) of the crop (Zhang et al., 2012).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Zhang et al., 2012 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 41

    Farrell et al. (2014) reported no significant effect on wheat yield at a low application rate (<1.0 Mg ha−1) of biochar in highly P-constrained calcareous soil, but a prominent effect of both biochar and fertilizer on P fractionation was observed.

    “Farrell et al. (2014) reported no significant effect on wheat yield at a low application rate (&lt;1.0 Mg ha -1 ) of biochar in highly P-constrained calcareous soil, but a prominent effect of both biochar and fertilizer on P fractionation was observed.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Farrell et al., 2014 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 39

    Plant biomass was significantly lower at higher biochar application rates (5 and 10 t ha−1), with a prominent impact on shoot production but also evident in grain yield and root biomass.

    “The plant biomass was significantly lower at higher biochar application rates (5 and 10 t ha -1 ), having a prominent impact on shoot production but also evident in grain yield and root biomass (Macdonald et al., 2014).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Macdonald et al., 2014 source

      Not checked in the free run.

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

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 43

    Biochar amendment showed an additional benefit on rice yield under N fertilizer application, and there was a close relationship between the effect of biochar amendment on rice yield and agronomic N use efficiency.

    “More interestingly, the same study further hinted that biochar amendment showed an additional benefit on rice yield under N fertilizer application, and there was a close relationship between the effect of biochar amendment on rice yield and agronomic N use efficiency.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Huang et al., 2013 source

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 39

    In acidic sandy soils, application of rice hull biochar (2% rate) prepared at 350-400°C increased sugarcane yield in Florida, USA, probably because biochar modulated nutrient enrichment in the soil.

    “In acidic sandy soils, the application of rice hull biochar (2% rate) prepared at 350-400 o C increased sugarcane yield in Florida, USA, probably because biochar modulated the nutrient enrichment in the soil (Alvarez-Campos et al., 2018).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Alvarez-Campos et al., 2018

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 40

    Fertilizer application along with carbonized rice husk (CRH-biochar) improved grain yields of rice, but the improvement was not always significant and even showed a decline in yield at Nitisol of Siniloan, Philippines.

    “Fertilizer application along with carbonized rice husk (CRH-biochar) improved the grain yields of rice, but the improvement was not always significant and even showed a decline in yield at Nitisol of Siniloan, Philippines (Haefele et al., 2011).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Haefele et al., 2011

      Not checked in the free run.

  • May combine two claims.

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 40

    Only in a gleyic Acrisols, application of CRH-biochar resulted in higher yield of rice in all four seasons, although significant increase was only observed in the third and fourth wet seasons.

    “Only in a gleyic Acrisols, the application of CRH-biochar resulted in a higher yield of rice in all four seasons, although the significant increase was only observed in the third and fourth wet seasons (Haefele et al., 2011).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Haefele et al., 2011

      Not checked in the free run.

  • Classified as probably not a substantial claim.

    Interpretationnone given
    § 10. Conclusions and future research directions · p. 46

    The mechanism through which the positive impacts of biochars on P and K occur is not clear yet.

    “The mechanism through which the positive impacts of biochars on P and K is not clear yet.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given
    § ACCEPTED MANUSCRIPT · p. 47

    The decrease in yield at higher biochar rate could be somewhat complemented by application of fertilizers along with biochar.

    “and mostly that could be somewhat complemented by application of fertilizers along with biochar.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation
    § ACCEPTED MANUSCRIPT · p. 43

    Such responses confirmed earlier results with moong bean, soybean, and pea, or with cowpea and rice.

    “Such responses confirmed earlier results with moong bean [ Vigna radiata (L.) R. Wilczek], soybean [ Glycine max (L.) Merr.], and pea ( Pisum sativum L.) (Iswaran et al., 1980), or with cowpea ( Vigna unguiculata L.) and rice ( Oryza sativa L.) (Nehls, 2002; Lehmann et al., 2003).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Iswaran et al., 1980 source

      Not checked in the free run.

    • cites Nehls, 2002

      Not checked in the free run.

    • cites Lehmann et al., 2003 source

      Not checked in the free run.

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given
    § ACCEPTED MANUSCRIPT · p. 47

    At a higher rate, biochar might decrease the yield of crops.

    “However, at a higher rate, biochar might decrease the yield of crops”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based).

    Interpretationnone given
    § 10. Conclusions and future research directions · p. 46

    Biochar produced from manure sources, being rich in N and other essential nutrients and having a narrow C:N ratio, could be of higher agronomic value.

    “However, biochar produced from manure sources being rich in N and other essential nutrients and having narrow C: N ratio could be of higher agronomic value.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationreasoning
    § ACCEPTED MANUSCRIPT · p. 47

    Biochar has positive, negative as well as neutral effects on crop productivity.

    “Biochar has positive, negative as well as neutral effects on crop productivity.”
    Quote in the paperSubstantial claim

  • Probably not a substantial claim: may not pass S3 (load-bearing), S4 (based). May combine two claims.

    Premisenone given
    § 10. Conclusions and future research directions · p. 46

    The majority of biochar is alkaline, except a few like oak and yellow pine chipped biochar, which is acidic.

    “The majority of biochar is alkaline, except a few like oak and yellow pine chipped biochar, which is acidic.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Interpretationcitation
    § ACCEPTED MANUSCRIPT · p. 45

    Increased temperature of biochar pyrolysis modifies the types of chemical functional groups on biochar carbon skeletons, which modifies the basicity of the biochar and thus the resulting pH of the soil amended by the biochar.

    “These observations may be explained by increased temperature of biochar pyrolysis resulting in modifications of the types of chemical functional groups (acidic versus ketonic) on the biochar carbon skeletons, which would modify the basicity of the biochar and thus the resulting pH of the soil which was amended by the biochar (Mandal et al., 2016; 2018).”
    Quote in the paperSubstantial claim0 of 1 sources checked
    • cites Mandal et al., 2016; 2018

      Not checked in the free run.

  • May combine two claims.

    Interpretationnone given
    § 10. Conclusions and future research directions · p. 46

    Many studies showed that biochar significantly influences the mineralization/immobilization turnover of N in soil, thereby controlling N availability without any definite conclusion.

    “Many studies showed that biochar significantly influences the mineralization/immobilization turnover of N in soil thereby controlling the N availability without any definite conclusion.”
    Quote in the paperSubstantial claim

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

    Interpretationreasoning
    § ACCEPTED MANUSCRIPT · p. 46

    It is likely that the low sample numbers and high diversity within the samples mean that not much information may be derived from the temperature-application rate-yield dataset by PCA.

    “It is likely that the low sample numbers and high diversity within the samples is such that not much information may be derived from the temperatureapplication rate-yield dataset by PCA.”
    Quote in the paperNot a substantial claim

  • Probably not a substantial claim: may not pass S1 (asserted), S3 (load-bearing), S4 (based).

    Interpretationnone given
    § ACCEPTED MANUSCRIPT · p. 45

    Greater application rates of biochar result in lower stimulation of crop yield.

    “This suggests an explanation counter to expectations that greater application rates of biochar result in lower stimulation of crop yield.”
    Quote in the paperNot a substantial claim
167 of 167

  • The paper relies on this without support.

    Soil nutrient availability for plants is pH dependent.

    “In soil, availability of nutrients for plants is pH dependent.”

  • The paper relies on this without support.

    A higher CEC soil can hold cationic nutrients in greater amounts and for longer time than a lower CEC soil, preventing nutrients from leaching loss and increasing their availabilities for plant uptake.

    “A higher CEC soil can hold cationic nutrients in greater amounts and for longer time than a lower CEC soil, preventing the nutrients from leaching loss and increasing their availabilities for plant uptake.”

  • The paper relies on this without support.

    Biochar is an alkaline material.

    “biochar being alkaline material neutralised the acidity.”
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?

  • As a source, biochar can supply nutrients such as nitrogen, phosphorus, potassium, and other trace elements inherently present in the original feedstock used for biochar production.

    “As a source, biochar can supply nutrients such as nitrogen (N), phosphorus (P), potassium (K), and other trace elements inherently present in the original feedstock used for biochar production (Purakayastha et al. 2019).”

    From Biochar and its importance on nutrient dynamics in soil and plant (2020) · cites this paper as Purakayastha et al. 2019

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.

  • Swine-solids zinc content differs by a factor of ten

    Minor

    The abstract gives the swine-solids biochar Zn content as 49,810 mg kg−1, while the main text gives 4,981 mg kg−1 for the same material.

  • Stated carbon-content range excludes higher values in Table 1

    Minor

    The text presents 81.2% as the upper end of the biochar carbon-content range, but Table 1 lists 87.8% for spruce and pine chips.

  • Digested-dairy-manure C/N ratio does not match listed contents

    Minor

    For the 600°C digested-dairy-manure biochar, Table 1 lists 59.4% C and 0.225% N. Their ratio is 264, not the reported 28.

    Reported 28 · recomputed 264

  • Cow-manure C/N ratio differs tenfold from listed contents

    Minor

    Table 1 lists 33.6% C and 0.15% N for cow-manure biochar, which yield a C/N ratio of 224 rather than 22.

    Reported 22 · recomputed 224

  • Calcium values are assigned to the opposite biochars

    Minor

    The text assigns approximately 25% Ca to paper-mill biochar and 31% to poultry-manure biochar. Table 1 instead lists 31.12% for paper-mill sludge and 24.28% for poultry manure at 600°C.

  • Claimed highest nitrogen content is below values in Table 1

    Minor

    The text calls manure-derived biochar the richest source of N and gives 4.45% as its high value. Table 1 lists 4.9% N for grass-waste biochar.

6 of 6

Cites

Flagged first, then by citations

5 of the 198 references couldn’t be matched to a known paper.

Research works printed but not linked: 6

  1. Gaskin, 2009, Characterization of char for agricultural use in the soils of the southeastern United States. Amazonian dark earths, Wim Sombroek's Vision, 433
  2. Lal, 1998, Flyash as a carrier for Rhizobium inoculant, J. Res., 10, 191
  3. Nishio, 1991, Stimulation of the growth of alfalfa and infection of my corrhizal fungi by the application of charcoal, Bull. Natl. Grassl. Res. Inst., 45, 61
  4. Pandher, 1993, Studies on growth and survival of Rhizobium isolates in different carriers, Indian J. Ecol., 20, 141
  5. Petersen, 1978, Some properties of two high-gradient extractors for soil microarthropods, and an attempt to evaluate their extraction efficiency, Nat. Jutl., 20, 95
  6. Rahman, 2014, Temperature effect on the characterization of pyrolysis products from oil palm fronds, Adv. Energy Eng., 2, 14

Cited by

Sorted by citations

Related

Authors
Purakayastha, T. J., Bera, T., Bhaduri, D., Sarkar, B., Mandal, S., Wade, P., Kumari, S., Biswas, S., Menon, M., Pathak, H., & Tsang, D. C. W.
Affiliations
  • Indian Council of Agricultural Research (IN)
  • University of Florida (US)
  • Central Rice Research Institute (IN)
  • University of Sheffield (GB)
  • Indian Agricultural Research Institute (IN)
  • Hong Kong Polytechnic University (HK)
Corresponding author
Purakayastha, T.J.
ORCID
Venue
Chemosphere
Publisher
Elsevier BV
Published
2019-07
Volume
227
Pages
345-365
ISSN
0045-6535 (ISSN-L)
DOI
10.1016/j.chemosphere.2019.03.170
OpenAlex
W2930814723
Semantic Scholar
55ba902c6f3e82741f1b9177492df6898ef63ac7
Cited by
379
References
198
Citations by year
2026: 47 · 2025: 50 · 2024: 79 · 2023: 62 · 2022: 44 · 2021: 56 · 2020: 32 · 2019: 8
FWCI
2.94
Type
journal article
Language
en
Open access
closed
Licence
Locations
  • Chemosphere (publishedVersion)
  • PubMed (publishedVersion)
  • White Rose Research Online (University of Leeds, The University of Sheffield, University of York) (acceptedVersion)
  • Adelaide Research & Scholarship (AR&S) (University of Adelaide) (submittedVersion)
  • Lancaster EPrints (Lancaster University) (submittedVersion)
  • Rare & Special e-Zone (The Hong Kong University of Science and Technology) (submittedVersion)
Funders
Indian Council of Agricultural Research
Topics
  • Life Sciences › Agricultural and Biological Sciences › Soil Science › Soil Carbon and Nitrogen Dynamics
  • Life Sciences › Agricultural and Biological Sciences › Soil Science › Agricultural Science and Fertilization
  • Physical Sciences › Engineering › Biomedical Engineering › Thermochemical Biomass Conversion Processes
Keywords
biochar, soil amendment, soil pH, soil nutrient availability, crop yield, pyrolysis temperature, soil carbon sequestration, cation exchange capacity, poultry litter biochar, soil alkalinity, climate change mitigation, food security, waste management
MeSH terms
Nutrients, Animals, Charcoal, Soil, Biomass, Crops, Agricultural

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.

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