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Cited by 439Soil Carbon and Nitrogen DynamicsSoil Management and Crop YieldSoil erosion and sediment transport

Breeding crop plants with deep roots: their role in sustainable carbon, nutrient and water sequestration

Open access
Kell, D. B.·2011·Annals of Botany
DOI 10.1093/aob/mcr175PMC PMC3158691
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Abstract

BACKGROUND: The soil represents a reservoir that contains at least twice as much carbon as does the atmosphere, yet (apart from 'root crops') mainly just the above-ground plant biomass is harvested in agriculture, and plant photosynthesis represents the effective origin of the overwhelming bulk of soil carbon. However, present estimates of the carbon sequestration potential of soils are based more on what is happening now than what might be changed by active agricultural intervention, and tend to concentrate only on the first metre of soil depth. SCOPE: Breeding crop plants with deeper and bushy root ecosystems could simultaneously improve both the soil structure and its steady-state carbon, water and nutrient retention, as well as sustainable plant yields. The carbon that can be sequestered in the steady state by increasing the rooting depths of crop plants and grasses from, say, 1 m to 2 m depends significantly on its lifetime(s) in different molecular forms in the soil, but calculations (http://dbkgroup.org/carbonsequestration/rootsystem.html) suggest that this breeding strategy could have a hugely beneficial effect in stabilizing atmospheric CO(2). This sets an important research agenda, and the breeding of plants with improved and deep rooting habits and architectures is a goal well worth pursuing.

AI snapshot

Written from the paper’s full text.

TL;DR

This review argues that breeding crop plants with deeper, bushier root systems could simultaneously improve soil carbon, nutrient and water retention while supporting sustainable yields. Using literature synthesis and simple calculations, it suggests that doubling root depth from about 1 m to 2 m could make a significant beneficial contribution to lowering atmospheric CO₂.

Key findings

  • Soil contains at least twice as much carbon as the atmosphere and three times that in vegetation; increasing soil carbon in the steady state by just 15% would lower atmospheric CO₂ by 30%.
  • Most cultivated agricultural crops have roots that do not extend much beyond 1 m, whereas 2 m is not uncommon for angiosperms, and at least five widely cultivated crop plants can produce roots exceeding 2 m.
  • Increasing root mass by an extra 1 m depth with just 1% carbon by volume equates to 10 kg m⁻² (100 t ha⁻¹), or on average 5 kg m⁻² (50 t ha⁻¹) if it turns over every 2 years; an extra 2% carbon over an extra 1 m equals 20 kg m⁻² (200 t ha⁻¹), or 100 t ha⁻¹ fixed on average in the steady state if the average carbon lifetime is 2 years.
  • To mop up fossil fuel carbon emissions of 8.4 Gt year⁻¹ at 50 t ha⁻¹ would require 1.6 × 10⁸ ha or 1.6 × 10⁶ km², compared with 41.4 × 10⁶ km² of rainfed arable land and 130.56 × 10⁶ km² of total land area excluding polar regions.

Methods

  • Design: a review/commentary that synthesizes literature on root architecture, maximum rooting depth, perenniality, no-till agriculture, soil carbon sequestration and plant breeding.
  • Data/sample: published literature and default values, including 2300 Mha of cropland and a similar amount of grassland, atmospheric carbon of 750–821 Pg, soil carbon of approx. 1500 Pg, and soil relative density of 1; calculations are made available at a linked web page.
  • Main analysis: conceptual synthesis plus simple arithmetic estimates of potential carbon sequestration from increasing root depth, explicitly without spatial analysis, economics, infrastructure issues, transitional arrangements, or time required to breed, bulk up and disseminate germplasm.

Limitations

  • The author states that a precise quantitative answer is impossible because sequestration is affected by many variables, so the paper provides only an approximation and makes no attempt to discriminate among known soil carbon pools.
  • The author states that the review does not discuss in detail interactions of roots with soil micro-organisms and other invertebrates, and that it is necessary to check whether deeper roots, especially if waterlogged and anaerobic, produce methane or nitrous oxide; possible positive or negative interactions with agricultural yield are also noted.
  • Evident from the text: as a brief commentary/review, it reports no systematic search or primary empirical validation, and its sequestration estimates depend on assumed carbon content, turnover/lifetime, and default land-area values.

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

Integrity signals

Registry

Crossref · 10.1093/aob/mcr175

Cites

299 of 299 references verified0 citation errors · 0 not checkable

Statistics

Nothing to recompute.

Claims the paper makes

0 of 130 cited sources checked · 0 supported · 0 flagged

  • Findingcitation

    Calculations suggest that breeding for deeper roots could have a hugely beneficial effect in stabilizing atmospheric CO2.

    “but calculations (http:// dbkgroup.org/carbonsequestration/rootsystem.html)suggest that this breeding strategy could have a hugely beneficial effect in stabilizing atmospheric CO 2 .”
    Quote in the paperSubstantial claim
  • Findingreasoning

    To mop up fossil fuel carbon at the rate of 50 t ha−1, some 1.6 × 10^8 ha or 1.6 × 10^6 km2 would be required.

    “and so to mop this up at the rate of 50 t ha 21 some 1 .6 × 10 8 ha or 1 .6 × 10 6 km 2 would be required.”
    Quote in the paperSubstantial claim
  • Premisecitation

    Roots lower erosion considerably.

    “and that roots lower erosion considerably (Gyssels et al., 2005).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Gyssels et al., 2005 source

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  • Premisecitation

    There are indications of a positive feedback in which increases in global temperature lower the ability of present soils and other parts of the biosphere to absorb CO2.

    “In addition, there are indications (Bellamy et al., 2005;Monson et al., 2006;Luo, 2007;Arnone et al., 2008;Bond-Lamberty and Thomson, 2010;Smith and Fang, 2010;Yvon-Durocher et al., 2010;Zhao and Running, 2010) of a positive feedback in which increases in global temperature lower the ability of present soils and other parts of the biosphere to absorb CO 2”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Bellamy et al., 2005 source

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    • cites Monson et al., 2006 source

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    • cites Luo, 2007

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  • Interpretationreasoning

    Increasing soil carbon in the steady state by just 15% would lower atmospheric CO2 by 30%.

    “Thus, increasing soil carbon in the steady state by just 15 % would lower atmospheric CO 2 by 30 %, offering a huge environmental benefit.”
    Quote in the paperSubstantial claim
  • May combine two claims. 22
  • Classified as probably not a substantial claim. 15
  • The quote only partly states this claim. 1

  • May combine two claims.

    Findingreasoning

    Increasing root mass by an extra 1 m depth with a very modest carbon content of just 1% carbon by volume of overall soil mass equates, assuming a relative density of 1, to 10 kg m−2 (100 t ha−1), or on average 5 kg m−2 (50 t ha−1) if it turns over every 2 years.

    “Increasing root mass by an extra 1 m depth with a very modest carbon content of just 1 % carbon by volume of overall soil mass equates (assuming a relative density of 1) to 10 kg m 22 (100 t ha 21 ), or on average 5 kg m 22 (50 t ha 21 ) if it turns over every 2 years.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Findingreasoning

    Calculations based on default values imply that an extra 2% of carbon occupying an extra 1 m depth over cropland and grassland areas equals 20 kg m−2 = 200 t ha−1, or, ignoring feedbacks, 100 t ha−1 fixed on average in the steady state if the lifetime of the average carbon held in different molecules is 2 years.

    “Calculations based on this imply that an extra 2 % of carbon occupying an extra 1 m depth over these areas ¼ 20 kg m 22 ¼ 200 t ha 21 (or, simplistically ignoring any feedbacks, 100 t ha 21 fixed on average in the steady state if the lifetime of the average 'carbon' held in different molecules is 2 years).”
    Quote in the paperSubstantial claim
    • The authors state this as an assumption: Feedbacks are ignored in the simplified calculation of steady-state carbon sequestration.

  • May combine two claims.

    Premisecitation

    The substantial decreases in atmospheric CO2 over geological time, especially during the Devonian and more gradually since the Cretaceous, have largely been effected via the production of deep-rooted trees and the rise of angiosperms, respectively.

    “Certainly it is recognized that the substantial ( possibly 10-or even 20-fold) decreases in atmospheric CO 2 over geological time, especially during the Devonian (416 .0 -359 . 2 Ma) and more gradually since the Cretaceous (145 .5-65 .5 Ma), have largely been effected via the production of deep-rooted trees and the rise of angiosperms, respectively (Mora et al., 1996;Berner, 1997;Berner and Kothav”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Mora et al., 1996 source

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    • cites Berner, 1997 source

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    • cites Berner and Kothavala, 2001

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

    Premisecitation

    Terrestrial and marine environments presently absorb about half of anthropogenic CO2.

    “Terrestrial and marine environments presently absorb about half the anthropogenic CO 2 (Schimel et al., 2001)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Schimel et al., 2001 source

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  • May combine two claims.

    Interpretationreasoning

    The goal of breeding plants with extended root systems that can effect carbon, water and nutrient sequestration is not only desirable but attainable.

    “Bringing them together indicates that the goal of breeding plants with extended root systems that can effect carbon, water and nutrient sequestration (Fig. 2) is not only desirable but attainable.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    There is evidence supporting the role of roots in improving soil structure, improving hydrology, and that SOC improves agronomic productivity.

    “As well as the benefits to carbon sequestration, there is evidence supporting the role of roots in improving soil structure (Gregory et al., 2010), on improving hydrology (Macleod et al., 2007) and in showing that SOC improves agronomic productivity (Lal, 2010b).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Gregory et al., 2010 source

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    • cites Macleod et al., 2007

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    • cites Lal, 2010b

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  • May combine two claims.

    Premisecitation

    Mycorrhizal fungi provide nutrients, especially phosphate, to plants, which in turn provide up to 20% of the carbon they fix to the soil-dwelling fungal partners.

    “The mycorrhizal fungi (of the genus Glomeromycota) provide nutrients, especially phosphate (Bucher, 2007), to the plants, which in turn provide up to 20 % of the carbon that they fix to the soil-dwelling fungal partners.”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Bucher, 2007 source

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

    Premisecitation

    Some very long-rooted plants common in arid zones are known as phreatophytes.

    “Some very long-rooted plants, common in arid zones, are known as phreatophytes (Pataki et al., 2008)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Pataki et al., 2008

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  • May combine two claims.

    Premisecitation

    There is considerable variation between plant types and individual cultivars as to the maximum depth to which they are known to produce roots, but 2 m for angiosperms (and much more for trees) is not at all uncommon.

    “There is considerable variation between both plant types and individual plant strains (cultivars) as to the maximum depth to which they are known to produce roots, but 2 m for angiosperms (and much more for trees) is not at all uncommon (Stone and Kalisz, 1991;Canadell et al., 1996;Jackson et al., 1996;Schenk and Jackson, 2002a, b;Hu et al., 2003)”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Stone and Kalisz, 1991

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    • cites Canadell et al., 1996

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    • cites Jackson et al., 1996

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  • May combine two claims.

    Premisecitation

    Most presently cultivated agricultural crops have root depths that do not extend much beyond 1 m, although a number do.

    “A chief point to note is that most presently cultivated agricultural crops have root depths that indeed do not extend much beyond 1 m, albeit that a number do (Kristensen and Thorup-Kristensen, 2004;Kutschera et al., 2009)”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Kristensen and Thorup-Kristensen, 2004

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    • cites Kutschera et al., 2009

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

    Premisecitation

    Root length is typically a function of aridity.

    “Root length is also typically a function of aridity (Canadell et al., 1996;Schenk andJackson, 2002a, 2005).”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Canadell et al., 1996

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    • cites Schenk andJackson, 2002a, 2005

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  • May combine two claims.

    Premisecitation

    Mycorrhiza secrete glomalin, whose extent correlates extremely well with desirable large aggregates in soil structure.

    “Mycorrhiza also secrete a protein called glomalin (Gadkar and Rillig, 2006), whose extent correlates extremely well with desirable (large aggregates in) soil structure (Bedini et al., 2009;Wilson et al., 2009).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Gadkar and Rillig, 2006

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    • cites Bedini et al., 2009

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    • cites Wilson et al., 2009 source

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  • May combine two claims.

    Premisecitation

    Some flowering time genes that contribute to perenniality seem to be conserved between monocots and dicots, in a way that root architecture is not.

    “though at least some flowering time genes that contribute to perenniality seem to be conserved between monocots and dicots (Wang et al., 2009;Higgins et al., 2010), in a way that root architecture is not (see above).”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Wang et al., 2009 source

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    • cites Higgins et al., 2010 source

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  • May combine two claims.

    Premisecitation

    Root architecture is controlled by hormonal influences from both the host plant and soil organisms, and to some degree by the physico-chemical environment.

    “As well as genetic means, root architecture is also controlled by hormonal influences from both the host plant (e.g.Tanimoto, 2005;Santner et al., 2009) and soil organisms (see above), and to some degree by the physico-chemical environment (e.g.Fitter and Stickland, 1991;Cahill et al., 2010).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Tanimoto, 2005

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    • cites Santner et al., 2009

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    • cites Fitter and Stickland, 1991

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  • May combine two claims.

    Interpretationreasoning

    The 50 t ha−1 number for carbon sequestration seems both conservative and reasonable.

    “so the 50 t ha 21 number seems both conservative and reasonable.”
    Quote in the paperSubstantial claim

  • May combine two claims.

    Premisecitation

    Gill and Jackson (2000) indicate a loss of 40% per year in temperate grasslands (i.e. a 'linear' lifetime of 2.5 years), with a greater decay as temperature increases.

    “but Gill and Jackson (2000) indicate a loss of 40 % per year in temperate grasslands (i.e. a 'linear' lifetime of 2 .5 years), with a greater decay as temperature increases”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Gill and Jackson (2000)

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

    Premisecitation

    Biochars are seen as especially recalcitrant.

    “Biochars (e.g.Lehmann, 2007;Atkinson et al., 2010;Sohi et al., 2010) are seen as especially recalcitrant.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Lehmann, 2007

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    • cites Atkinson et al., 2010

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    • cites Sohi et al., 2010

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  • May combine two claims.

    Interpretationcitation

    The role of genetics or plant breeding in increasing root depth is not negligible; root depth is not governed entirely by the physico-chemical properties of the soil.

    “The experimental facts are against this (Doussan et al., 2003;Kato et al., 2006), and a number of simple gene-based arguments show that this is not the case.”
    Quote in the paperSubstantial claim0 of 2 sources checked
    • cites Doussan et al., 2003

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    • cites Kato et al., 2006

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  • May combine two claims.

    Premisecitation

    Data on the longevity of soil roots and the pools of carbon obtained therefrom in the soil are both uncertain and not very easy to come by.

    “However, data on the longevity of soil roots and the (other) pools of carbon that are obtained therefrom in the soil (Zimmermann et al., 2007;Smith et al., 2010b) (let alone their variation with depth, soil type, vegetation type, etc.) are both uncertain and not very easy to come by (Baggs, 2006;Gregory, 2006;Kuzyakov, 2006;Koerber et al., 2010;Sanderman and Baldock, 2010)”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Zimmermann et al., 2007

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    • cites Smith et al., 2010b

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    • cites Baggs, 2006

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  • May combine two claims.

    Premisecitation

    No-till agriculture assists carbon sequestration and decreases soil erosion.

    “Ploughing releases SOC and, in a similar vein, no-till agriculture (that may also be used with perennial crops) assists carbon sequestration and decreases soil erosion (e.g.Paustian et al., 2000;West and Post, 2002;Sainju et al., 2003;Lal et al., 2004;Bernacchi et al., 2005;Amado et al., 2006;Montgomery, 2007;Huggins and Reganold, 2008;Villamil et al., 2008;Lo ´pez-Bellido et al., 2010)”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Paustian et al., 2000

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    • cites West and Post, 2002 source

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    • cites Sainju et al., 2003

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  • May combine two claims.

    Interpretationreasoning

    Doubling root biomass from a nominal 1 m to a nominal 2 m is the key issue, together with the longevity of the roots and carbon they secrete and sequester below-ground.

    “This doubling of root biomass from a nominal 1 m to a nominal 2 m is really the key issue, together with the longevity of the roots and carbon they secrete and sequester below-ground (a complete turnover annually, including of stover in no-till systems, obviously gives no net steady-state sequestration).”
    Quote in the paperSubstantial claim

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

    Interpretationreasoning

    Tillage of surface layers that do not disturb deeper roots becomes at least partially a no-till process.

    “although tillage of surface layers that do not disturb deeper roots becomes at least partially a no-till process (see also Fig. 2).”
    Quote in the paperNot a substantial claim

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

    Interpretationnone given

    What matters for carbon sequestration is not so much what is happening now as what might be achieved with suitable breeding of plants with deep and reasonably long-lived roots.

    “The point, though, is that what matters is not so much what is happening now as what might be achieved with suitable breeding of plants with deep (and reasonably long-lived) roots.”
    Quote in the paperNot a substantial claim

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

    Premisecitation

    Gross global primary production exceeds 100 Pg year−1.

    “with gross global primary production exceeding 100 Pg year 21 (Beer et al., 2010).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Beer et al., 2010

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

    Premisecitation

    Forests typically sequester even more carbon than grasslands and energy crops.

    “[forests typically sequester even more (Malhi et al., 1999)]”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Malhi et al., 1999

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  • May combine two claims.

    Interpretationreasoning

    Unless marine carbon storage could be effected in a recalcitrant form that sinks rapidly, CO2 should probably best be sequestered elsewhere if we are to have ecosystems in which the net ecosystem carbon budget is accumulative.

    “Unless marine carbon storage could be effected in a recalcitrant form that sinks rapidly (Jiao et al., 2010;Stone, 2010;Jiao and Azam, 2011), this implies that CO 2 should probably best be sequestered elsewhere if we are to have ecosystems in which the net ecosystem carbon budget (Chapin et al., 2006;Smith et al., 2010b) is accumulative.”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Jiao et al., 2010 source

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    • cites Stone, 2010 source

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    • cites Jiao and Azam, 2011

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

    Premisecitation

    Soil biota and roots help increase the porosity of soil.

    “A couple of examples include the facts that the soil biota (and roots) help increase the porosity of soil (Feeney et al., 2006)”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Feeney et al., 2006 source

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  • May combine two claims.

    Interpretationreasoning

    Breeding crop plants with deeper and bushy root ecosystems could simultaneously improve both the soil structure and its steady-state carbon, water and nutrient retention, as well as sustainable plant yields.

    “Breeding crop plants with deeper and bushy root ecosystems could simultaneously improve both the soil structure and its steady-state carbon, water and nutrient retention, as well as sustainable plant yields.”
    Quote in the paperSubstantial claim

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

    Premisecitation

    A number of experts have given a slightly less optimistic view of the potential of land use changes to improve carbon sequestration.

    “It is certainly the case that a number of experts have given a slightly less optimistic view of the potential of land use changes to improve carbon sequestration (Smith, 2004;van Kessel et al., 2006;Soussana and Luscher, 2007;Ciais et al., 2010;Smith et al., 2010a) (but see Lal, 2010a).”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Smith, 2004

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    • cites van Kessel et al., 2006

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    • cites Soussana and Luscher, 2007

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

    Interpretationreasoning

    Changes in agricultural practice are needed.

    “This implies changes in agricultural practice (Robertson et al., 2000;Lal, 2004Lal, , 2008aLal, , b, 2011;;Sartori et al., 2006;Pretty, 2008;Smith et al., 2008;Burney et al., 2010;Follett and Reed, 2010;Smith and Olesen, 2010;Powlson et al., 2011)”
    Quote in the paperNot a substantial claim0 of 3 sources checked
    • cites Robertson et al., 2000 source

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    • cites Lal, 2004 source

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    • cites Pretty, 2008

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  • The quote only partly states this claim.

    Interpretationreasoning

    Crops with very extensive root systems reduce fertilizer runoff.

    “as well as to fertilizer runoff”
    Quote in the paperSubstantial claim

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

    Premisecitation

    Oceans contain approximately 50 or more times the CO2 than does the atmosphere.

    “Oceans contain approx.50 or more times the CO 2 than does the atmosphere (Smith, 2004;MacKay, 2008)”
    Quote in the paperNot a substantial claim0 of 2 sources checked
    • cites Smith, 2004

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    • cites MacKay, 2008

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

    Premisecitation

    Roots both affect the physical architecture of soils and vice versa.

    “and that roots both affect the physical architecture of soils and vice versa (Hinsinger et al., 2009).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Hinsinger et al., 2009

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

    Premisecitation

    There are some 41.4 × 10^6 km2 of just rainfed arable land, and 130.56 × 10^6 km2 of total land area excluding polar regions.

    “This compares with some 41 .4 × 10 6 km 2 (Bot et al., 2000) of just rainfed arable land, and 130 .56. 10 6 km 2 of total land area excluding polar regions (http://www .worldmapper.org/).”
    Quote in the paperNot a substantial claim0 of 1 sources checked
    • cites Bot et al., 2000

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

    Interpretationreasoning

    Increasing the amount of below-ground biomass en route to sequestering atmospheric CO2 is a desirable goal.

    “The required changes in agricultural practice, plus the existence of proof that carbon was indeed once highly sequestered in plant biomass, led to the recognition that increasing the amount of below-ground biomass en route to sequestering atmospheric CO 2 is a desirable goal.”
    Quote in the paperNot a substantial claim

  • May combine two claims.

    Premisecitation

    Increased dissolution of atmospheric CO2 in oceans and lakes leads to their further acidification, with many undesirable consequences.

    “but increased dissolution of atmospheric CO 2 in oceans (and lakes) leads to their further acidification, with many undesirable consequences (Sabine et al., 2004;Orr et al., 2005;Riebesell et al., 2007;Hall-Spencer et al., 2008;McNeil and Matear, 2008;Reid et al., 2009;Doney, 2010;Shi et al., 2010;Turley et al., 2010).”
    Quote in the paperSubstantial claim0 of 3 sources checked
    • cites Sabine et al., 2004 source

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    • cites Orr et al., 2005 source

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    • cites Riebesell et al., 2007 source

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36 of 36

  • The paper relies on this without support.

    The greenhouse effect means that temperatures will rise monotonically with increased levels of atmospheric CO2 and other greenhouse gases.

    “Whatever the extent and dynamics of increased levels of atmospheric CO 2 [and of other greenhouse gases (GHGs), for which similar arguments apply], the greenhouse effect means that temperatures will rise monotonically with their levels.”

  • The paper relies on this without support.

    Present estimates of the carbon sequestration potential of soils are based more on what is happening now than what might be changed by active agricultural intervention, and tend to concentrate only on the first metre of soil depth.

    “However, present estimates of the carbon sequestration potential of soils are based more on what is happening now than what might be changed by active agricultural intervention, and tend to concentrate only on the first metre of soil depth.”

  • The authors state this as an assumption.

    Feedbacks are ignored in the simplified calculation of steady-state carbon sequestration.

    “or, simplistically ignoring any feedbacks, 100 t ha 21 fixed on average in the steady state if the lifetime of the average 'carbon' held in different molecules is 2 years”

  • The paper relies on this without support.

    Carbon sequestration by crops with very extensive root systems is possibly double that of common annual grain crops.

    “possibly double that of common annual grain crops”
4 of 4

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?

  • Rhizodeposition and root exudates can cause a priming effect on the turnover of stored soil carbon, which could increase soil carbon emission and lower the sequestration rate.

    “Rhizodeposition and root exudates can cause a priming effect on the turnover of C stored in the soil [100], which could increase soil C emission [101, 102] and lower the sequestration rate.”

    From Carbon Sequestration by Perennial Energy Crops: Is the Jury Still Out? (2015) · cites this paper as [101]

  • Physical protection and chemical adsorption, both controlled by soil texture such as clay content and cation exchange capacity, may play an important role for long-term carbon retention.

    “However, physical protection and chemical adsorption, both controlled by soil texture (e.g. clay content and cation exchange capacity), may play an important role for long-term C retention [4, 34, 35, 101].”

    From Carbon Sequestration by Perennial Energy Crops: Is the Jury Still Out? (2015) · cites this paper as [101]

Cites

Flagged first, then by citations

Research works printed but not linked: 8

  1. 2006, Current Science, 90, 835
  2. 2004, 123, 1
  3. 2009, Current Science, 97, 618
  4. 2010, SCIENCE CHINALIFE SCIENCES, 53, 868
  5. 2010, ENVIRONMENTAL RESEARCH LETTERS, 5, 1
  6. 2005, 126, 129
  7. 2008, 146, 326
  8. 2010, 156, 1

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Authors
Kell, D. B.
Affiliations
Biotechnology and Biological Sciences Research Council (GB)
Corresponding author
Kell, D. B.
ORCID
Kell, D. B.
Venue
Annals of Botany
Publisher
Oxford University Press (OUP)
Published
2011-08-03
Volume
108
Issue
3
Pages
407-418
ISSN
  • 0305-7364 (ISSN-L)
  • 1095-8290
DOI
10.1093/aob/mcr175
PMC
PMC3158691
OpenAlex
W2125340135
Semantic Scholar
a9a7069ca44a4821ba5faa66a056d03e3bc08d56
Cited by
439
References
299
Citations by year
2026: 31 · 2025: 39 · 2024: 31 · 2023: 35 · 2022: 47 · 2021: 33 · 2020: 41 · 2019: 27 · 2018: 31 · 2017: 30 · 2016: 18 · 2015: 18 · 2014: 18 · 2013: 19 · 2012: 19
FWCI
3.57
Type
journal article
Language
en
Open access
Locations
  • Annals of Botany (publishedVersion)
  • Europe PMC (PubMed Central) (publishedVersion)
  • PubMed Central (publishedVersion)
  • PubMed (publishedVersion)
  • Research Explorer (The University of Manchester) (submittedVersion)
Topics
  • Life Sciences › Agricultural and Biological Sciences › Soil Science › Soil Carbon and Nitrogen Dynamics
  • Life Sciences › Agricultural and Biological Sciences › Soil Science › Soil Management and Crop Yield
  • Life Sciences › Agricultural and Biological Sciences › Soil Science › Soil erosion and sediment transport
Keywords
deep rooting, crop breeding, soil carbon sequestration, root architecture, soil water retention, nutrient retention, soil structure, root crops, atmospheric CO2 stabilization, sustainable agriculture, plant breeding
MeSH terms
Breeding, Carbon, Carbon Dioxide, Soil, Water, Plant Roots, Biomass, Crops, Agricultural, Carbon Sequestration

About these checks

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

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

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

Statistics and arithmetic are recomputed, not judged.

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

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

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