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Sampling for Soil Carbon Stock Assessment in Rocky Agricultural SoilsCoring methods commonly employed in soil organic C (SOC) stock assessment may not accurately capture soil rock fragment (RF) content or soil bulk density (rho (sub b)) in rocky agricultural soils, potentially biasing SOC stock estimates. Quantitative pits are considered less biased than coring methods but are invasive and often cost-prohibitive. We compared fixed-depth and mass-based estimates of SOC stocks (0.3-meters depth) for hammer, hydraulic push, and rotary coring methods relative to quantitative pits at four agricultural sites ranging in RF content from less than 0.01 to 0.24 cubic meters per cubic meter. Sampling costs were also compared. Coring methods significantly underestimated RF content at all rocky sites, but significant differences (p is less than 0.05) in SOC stocks between pits and corers were only found with the hammer method using the fixed-depth approach at the less than 0.01 cubic meters per cubic meter RF site (pit, 5.80 kilograms C per square meter; hammer, 4.74 kilograms C per square meter) and at the 0.14 cubic meters per cubic meter RF site (pit, 8.81 kilograms C per square meter; hammer, 6.71 kilograms C per square meter). The hammer corer also underestimated rho (sub b) at all sites as did the hydraulic push corer at the 0.21 cubic meters per cubic meter RF site. No significant differences in mass-based SOC stock estimates were observed between pits and corers. Our results indicate that (i) calculating SOC stocks on a mass basis can overcome biases in RF and rho (sub b) estimates introduced by sampling equipment and (ii) a quantitative pit is the optimal sampling method for establishing reference soil masses, followed by rotary and then hydraulic push corers.
Document ID
20160012559
Document Type
Reprint (Version printed in journal)
Authors
Beem-Miller, Jeffrey P.
(Cornell Univ. Ithaca, NY, United States)
Kong, Angela Y. Y.
(Columbia Univ. New York, NY, United States)
Ogle, Stephen
(Colorado State Univ. Fort Collins, CO, United States)
Wolfe, David
(Cornell Univ. Ithaca, NY, United States)
Date Acquired
October 24, 2016
Publication Date
August 30, 2016
Publication Information
Publication: Soil Science Society of America Journal
Volume: 80
Issue: 5
Subject Category
Life Sciences (General)
Geophysics
Report/Patent Number
GSFC-E-DAA-TN36555
Funding Number(s)
CONTRACT_GRANT: NNX14AB99A
Distribution Limits
Public
Copyright
Other
Keywords
hammer method
soil mass
coring methods
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