When bulk density methods matter

Implications for estimating soil organic carbon pools in rocky soils

Heather Throop, S. R. Archer, H. C. Monger, S. Waltman

Research output: Contribution to journalArticle

82 Citations (Scopus)

Abstract

Resolving uncertainty in the carbon cycle is paramount to refining climate predictions. Soil organic carbon (SOC) is a major component of terrestrial C pools, and accuracy of SOC estimates are only as good as the measurements and assumptions used to obtain them. Dryland soils account for a substantial portion of global SOC, but the pool dynamics are highly uncertain. One crucial component of accurate estimates of SOC on an areal basis is bulk density (ρb), the mass of soil per unit volume. Here, we review methods used for calculating ρb and assess their prevalence. We show how treatment of coarse fragments (particles >2 mm diameter) influences ρb values and discuss the implications for SOC estimates in drylands. In four dryland examples, methods that varied in their treatment of coarse fragments led to substantial (up to 26%) differences in ρb. Calculated SOC pools responded proportionally, with SOC differing by up to 518 g C m-2. We suggest a revised method for accounting for coarse fractions in ρb calculations. A large portion of the world's soils, particularly in drylands, are fine enough to allow ρb determination with cores, but contain coarse fragments that substantially impact SOC mass estimates if not explicitly considered.

Original languageEnglish (US)
Pages (from-to)66-71
Number of pages6
JournalJournal of Arid Environments
Volume77
Issue number1
DOIs
StatePublished - Feb 2012
Externally publishedYes

Fingerprint

carbon sinks
soil organic carbon
bulk density
organic carbon
arid lands
soil
methodology
method
refining
climate prediction
uncertainty
carbon cycle
climate
prediction

Keywords

  • Carbon accounting
  • Carbon pools
  • Core method
  • Soil carbon

ASJC Scopus subject areas

  • Ecology, Evolution, Behavior and Systematics
  • Earth-Surface Processes
  • Ecology

Cite this

When bulk density methods matter : Implications for estimating soil organic carbon pools in rocky soils. / Throop, Heather; Archer, S. R.; Monger, H. C.; Waltman, S.

In: Journal of Arid Environments, Vol. 77, No. 1, 02.2012, p. 66-71.

Research output: Contribution to journalArticle

@article{c594874ee379452b93e876365102b8d2,
title = "When bulk density methods matter: Implications for estimating soil organic carbon pools in rocky soils",
abstract = "Resolving uncertainty in the carbon cycle is paramount to refining climate predictions. Soil organic carbon (SOC) is a major component of terrestrial C pools, and accuracy of SOC estimates are only as good as the measurements and assumptions used to obtain them. Dryland soils account for a substantial portion of global SOC, but the pool dynamics are highly uncertain. One crucial component of accurate estimates of SOC on an areal basis is bulk density (ρb), the mass of soil per unit volume. Here, we review methods used for calculating ρb and assess their prevalence. We show how treatment of coarse fragments (particles >2 mm diameter) influences ρb values and discuss the implications for SOC estimates in drylands. In four dryland examples, methods that varied in their treatment of coarse fragments led to substantial (up to 26{\%}) differences in ρb. Calculated SOC pools responded proportionally, with SOC differing by up to 518 g C m-2. We suggest a revised method for accounting for coarse fractions in ρb calculations. A large portion of the world's soils, particularly in drylands, are fine enough to allow ρb determination with cores, but contain coarse fragments that substantially impact SOC mass estimates if not explicitly considered.",
keywords = "Carbon accounting, Carbon pools, Core method, Soil carbon",
author = "Heather Throop and Archer, {S. R.} and Monger, {H. C.} and S. Waltman",
year = "2012",
month = "2",
doi = "10.1016/j.jaridenv.2011.08.020",
language = "English (US)",
volume = "77",
pages = "66--71",
journal = "Journal of Arid Environments",
issn = "0140-1963",
publisher = "Academic Press Inc.",
number = "1",

}

TY - JOUR

T1 - When bulk density methods matter

T2 - Implications for estimating soil organic carbon pools in rocky soils

AU - Throop, Heather

AU - Archer, S. R.

AU - Monger, H. C.

AU - Waltman, S.

PY - 2012/2

Y1 - 2012/2

N2 - Resolving uncertainty in the carbon cycle is paramount to refining climate predictions. Soil organic carbon (SOC) is a major component of terrestrial C pools, and accuracy of SOC estimates are only as good as the measurements and assumptions used to obtain them. Dryland soils account for a substantial portion of global SOC, but the pool dynamics are highly uncertain. One crucial component of accurate estimates of SOC on an areal basis is bulk density (ρb), the mass of soil per unit volume. Here, we review methods used for calculating ρb and assess their prevalence. We show how treatment of coarse fragments (particles >2 mm diameter) influences ρb values and discuss the implications for SOC estimates in drylands. In four dryland examples, methods that varied in their treatment of coarse fragments led to substantial (up to 26%) differences in ρb. Calculated SOC pools responded proportionally, with SOC differing by up to 518 g C m-2. We suggest a revised method for accounting for coarse fractions in ρb calculations. A large portion of the world's soils, particularly in drylands, are fine enough to allow ρb determination with cores, but contain coarse fragments that substantially impact SOC mass estimates if not explicitly considered.

AB - Resolving uncertainty in the carbon cycle is paramount to refining climate predictions. Soil organic carbon (SOC) is a major component of terrestrial C pools, and accuracy of SOC estimates are only as good as the measurements and assumptions used to obtain them. Dryland soils account for a substantial portion of global SOC, but the pool dynamics are highly uncertain. One crucial component of accurate estimates of SOC on an areal basis is bulk density (ρb), the mass of soil per unit volume. Here, we review methods used for calculating ρb and assess their prevalence. We show how treatment of coarse fragments (particles >2 mm diameter) influences ρb values and discuss the implications for SOC estimates in drylands. In four dryland examples, methods that varied in their treatment of coarse fragments led to substantial (up to 26%) differences in ρb. Calculated SOC pools responded proportionally, with SOC differing by up to 518 g C m-2. We suggest a revised method for accounting for coarse fractions in ρb calculations. A large portion of the world's soils, particularly in drylands, are fine enough to allow ρb determination with cores, but contain coarse fragments that substantially impact SOC mass estimates if not explicitly considered.

KW - Carbon accounting

KW - Carbon pools

KW - Core method

KW - Soil carbon

UR - http://www.scopus.com/inward/record.url?scp=81055140295&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=81055140295&partnerID=8YFLogxK

U2 - 10.1016/j.jaridenv.2011.08.020

DO - 10.1016/j.jaridenv.2011.08.020

M3 - Article

VL - 77

SP - 66

EP - 71

JO - Journal of Arid Environments

JF - Journal of Arid Environments

SN - 0140-1963

IS - 1

ER -