@article{fdi:010064038,
  title = {{S}oil aggregate stability to predict organic carbon outputs from soils},
  author = {{C}haplot, {V}incent and {C}ooper, {M}.},
  editor = {},
  language = {{ENG}},
  abstract = {{S}oil structure (e.g. aggregation) has been recognized as a key element in the stabilization of soil organic matter. {W}hile aggregate bre akdown is assumed to expose the enclosed soil organic carbon ({SOC}) to preferential erosion and to accelerated decomposition, the link between the stability of soil aggregates and {SOC} exports from soils, has either been overlooked or unaccounted for, especially when developing carbon cycle models. {T}his study compared {SOC} losses in particulate ({POC}), dissolved ({DOC}) and gaseous ({GOC}) forms to an indicator of the soil aggregate stability, the mean weight diameter of aggregates ({MWD}). {SOC} outputs were considered at 24 locations of a typical hillslope of the {S}outh {A}frican {H}ighveld showing clayey to sandy soils. {B}oth {POC} and {DOC} were evaluated in-situ under natural rains using 1 x 1 m(2) runoff plots while soil {CO}2 emissions were assessed in the laboratory from undisturbed 0-0.05 m soil samples. {MWD} was finally compared to selected soil and terrain attributes for predictive purpose and as a means to further the understanding of {SOC} outputs from soils. {MWD} ranged between 1.4 mm for unstable aggregates and 3.4 mm for stable aggregates. {T}he increase in aggregate stability resulted in a significant increase in {POC} and {DOC} concentrations in the eroded sediments (r = 0.76) and in {GOC} losses from soils (r = 0.91 when expressed as g {C}-{CO}2 per gram of soil; r = 0.95 when as g {C}-{CO}2 per gram of soil carbon). {I}n contrast, high aggregate stability induced low total {DOC} and {POC} losses (r = -0.81 and -0.77, respectively). {T}he lower {POC} and {DOC} losses in the most stable soil aggregates were explained by increased soil infiltration by water and reduced transport by runoff, while the greater {CO}2 emissions correlated with high {SOC} concentration. {F}urthermore, there was a tendency for clayey soils which were fully covered by grass to present stable aggregates and thus to yield greater {CO}2 emissions but lower {POC} and {DOC} outputs than degraded sandy soils of low aggregate stability. {S}uch a quantitative assessment of the role of soil aggregation on {SOC} outputs might enhance knowledge on organic matter persistence in soils, a prerequisite for developing more accurate global carbon cycle models. {F}inally further research is required to investigate the downslope to downstream fate of the eroded {SOC} and to develop land management strategies that aim at lessening carbon losses from soils while enhancing adaptation to climate change.},
  keywords = {{W}ater erosion ; {S}oil ; {M}ultivariate analysis ; {S}oil degradation ; {AFRIQUE} {DU} {SUD}},
  booktitle = {},
  journal = {{G}eoderma},
  volume = {243},
  numero = {},
  pages = {205--213},
  ISSN = {0016-7061},
  year = {2015},
  DOI = {10.1016/j.geoderma.2014.12.013},
  URL = {https://www.documentation.ird.fr/hor/fdi:010064038},
}