Mechanisms underlying limited soil carbon gains in perennial and cover‐cropped bioenergy systems revealed by stable isotopes

dc.contributor.author Ye, Chenglong
dc.contributor.author Hall, Steven
dc.contributor.author Hall, Steven
dc.contributor.department Ecology, Evolution and Organismal Biology
dc.date 2019-11-12T22:05:04.000
dc.date.accessioned 2020-06-30T02:18:31Z
dc.date.available 2020-06-30T02:18:31Z
dc.date.copyright Tue Jan 01 00:00:00 UTC 2019
dc.date.issued 2019-01-01
dc.description.abstract <p>Removal of biomass for bioenergy production may decrease soil organic carbon. While perennials or cover‐cropped grains often have greater root production than annual grain crops, they variably impact soil carbon and underlying mechanisms remain unclear. We used high‐frequency measurements of soil respiration and natural abundance carbon stable isotopes to differentiate respiration sources, pool sizes, and decomposition rate constants during a 10 month incubation of soils collected to 1 m depth from a 10 year old field experiment in Iowa, United States. Conversion of corn–soybean rotations to reconstructed prairies or addition of a rye cover crop to continuous corn significantly altered respiration sources and dynamics of fast‐ and slow‐cycling carbon (turnover times of weeks to months–years, respectively), but had little effect on bulk soil carbon and several extractable pools (except in fertilized prairie). Both unfertilized and fertilized prairies increased slow‐cycling carbon pools relative to annual crops, but only in 0–25 cm soil. Compared with fertilized prairie, the unfertilized prairie significantly increased decomposition rates of fast‐ and slow‐cycling carbon pools in 0–25 cm soil, likely explaining the lack of significant bulk soil carbon accrual despite twofold greater root production. Carbon derived from C4 plants decomposed faster than C3‐derived carbon across all depths and cropping systems and contributions of C3‐carbon to respiration increased with depth. Respiration of cover crop‐derived carbon was greatest in 0–25 cm soil but comprised >25% of respiration below 25 cm, implying a disproportionate impact of the cover crop on deep soil metabolism. However, the cover crop also increased the decomposition rates of fast‐ and slow‐cycling carbon pools and decreased their pool sizes across all depths relative to corn without a cover crop. Despite their notable environmental benefits, neither unfertilized perennials nor cover crops necessarily promote rapid soil carbon sequestration relative to conventional annual bioenergy systems because of concomitant increases in decomposition.</p>
dc.description.comments <p>This article is published as Ye, Chenglong, and Steven J. Hall. "Mechanisms underlying limited soil carbon gains in perennial and cover‐cropped bioenergy systems revealed by stable isotopes." <em>GCB Bioenergy</em> (2019). doi: <a href="https://doi.org/10.1111/gcbb.12657">10.1111/gcbb.12657</a>.</p>
dc.format.mimetype application/pdf
dc.identifier archive/lib.dr.iastate.edu/eeob_ag_pubs/379/
dc.identifier.articleid 1386
dc.identifier.contextkey 15760909
dc.identifier.s3bucket isulib-bepress-aws-west
dc.identifier.submissionpath eeob_ag_pubs/379
dc.identifier.uri https://dr.lib.iastate.edu/handle/20.500.12876/23263
dc.language.iso en
dc.source.bitstream archive/lib.dr.iastate.edu/eeob_ag_pubs/379/2019_Hall_MechanismsUnderlying.pdf|||Fri Jan 14 23:51:26 UTC 2022
dc.source.uri 10.1111/gcbb.12657
dc.subject.disciplines Agricultural Science
dc.subject.disciplines Ecology and Evolutionary Biology
dc.subject.disciplines Oil, Gas, and Energy
dc.subject.disciplines Soil Science
dc.subject.keywords C3 and C4 plants
dc.subject.keywords carbon sequestration
dc.subject.keywords carbon stable isotopes
dc.subject.keywords carbonate
dc.subject.keywords cover crop
dc.subject.keywords deep soil
dc.subject.keywords no‐till
dc.subject.keywords reconstructed prairie
dc.subject.keywords soil respiration
dc.title Mechanisms underlying limited soil carbon gains in perennial and cover‐cropped bioenergy systems revealed by stable isotopes
dc.type article
dc.type.genre article
dspace.entity.type Publication
relation.isAuthorOfPublication 3f4318fa-b172-4017-b69d-49d5e3607c4f
relation.isOrgUnitOfPublication 6fa4d3a0-d4c9-4940-945f-9e5923aed691
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