Soil organic matter is stabilized by organo-mineral associations through two key processes: The role of the carbon to nitrogen ratio
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Soil organic matter is stabilized by organo-mineral associations through two key processes : The role of the carbon to nitrogen ratio. / Kopittke, Peter M.; Dalal, Ram C.; Hoeschen, Carmen; Li, Cui; Menzies, Neal W.; Mueller, Carsten W.
In: Geoderma, Vol. 357, 113974, 2020.Research output: Contribution to journal › Journal article › Research › peer-review
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T1 - Soil organic matter is stabilized by organo-mineral associations through two key processes
T2 - The role of the carbon to nitrogen ratio
AU - Kopittke, Peter M.
AU - Dalal, Ram C.
AU - Hoeschen, Carmen
AU - Li, Cui
AU - Menzies, Neal W.
AU - Mueller, Carsten W.
PY - 2020
Y1 - 2020
N2 - The loss of organic matter (OM) from soil during long-term agricultural cropping results in a decrease in the inherent fertility of the soil as well as releasing greenhouse gases. Despite the importance of organo-mineral associations in the stabilization of OM within soils, much remains unknown about these organo-mineral associations. We used nano-scale secondary ion mass spectrometry (NanoSIMS) to investigate the incorporation and stabilization of 13C and 15N labelled residues of lucerne (Medicago sativa) and buffel grass (Cenchrus ciliaris) when incubated in a Vertisol from temperate Australia for up to 365 d. We show that newly-added OM forms organo-mineral associations through two mechanisms. Firstly, it was observed that the newly-added OM forms associations with the existing mineral-bound OM. However, this apparent stabilization of newly-added OM by associating with existing mineral-bound OM was not influenced by the C:N ratio of the plant residues, with the lucerne residues (C:N ratio of 11) being incorporated to a similar extent as the buffel grass (C:N ratio of 35). Secondly, we observed that N-rich microbial metabolites attached directly to mineral particle surfaces that did not contain existing OM patches, thereby creating new organo-mineral associations through which additional stabilization of OM would be possible. The information obtained in this study is valuable in understanding the stabilization of OM through organo-mineral associations, and raises the possibility of using cover crops or catch crops with narrow C:N ratios to allow for formation of new organo-mineral associations for increased stabilization of OM in soil.
AB - The loss of organic matter (OM) from soil during long-term agricultural cropping results in a decrease in the inherent fertility of the soil as well as releasing greenhouse gases. Despite the importance of organo-mineral associations in the stabilization of OM within soils, much remains unknown about these organo-mineral associations. We used nano-scale secondary ion mass spectrometry (NanoSIMS) to investigate the incorporation and stabilization of 13C and 15N labelled residues of lucerne (Medicago sativa) and buffel grass (Cenchrus ciliaris) when incubated in a Vertisol from temperate Australia for up to 365 d. We show that newly-added OM forms organo-mineral associations through two mechanisms. Firstly, it was observed that the newly-added OM forms associations with the existing mineral-bound OM. However, this apparent stabilization of newly-added OM by associating with existing mineral-bound OM was not influenced by the C:N ratio of the plant residues, with the lucerne residues (C:N ratio of 11) being incorporated to a similar extent as the buffel grass (C:N ratio of 35). Secondly, we observed that N-rich microbial metabolites attached directly to mineral particle surfaces that did not contain existing OM patches, thereby creating new organo-mineral associations through which additional stabilization of OM would be possible. The information obtained in this study is valuable in understanding the stabilization of OM through organo-mineral associations, and raises the possibility of using cover crops or catch crops with narrow C:N ratios to allow for formation of new organo-mineral associations for increased stabilization of OM in soil.
KW - Nano-scale secondary ion mass spectrometry (NanoSIMS)
KW - Organo-mineral interactions
KW - Soil carbon cycling
KW - Soil carbon storage
KW - Stable isotopes
U2 - 10.1016/j.geoderma.2019.113974
DO - 10.1016/j.geoderma.2019.113974
M3 - Journal article
AN - SCOPUS:85072189232
VL - 357
JO - Geoderma
JF - Geoderma
SN - 0016-7061
M1 - 113974
ER -
ID: 238948198