@article{fdi:010036713,
  title = {{M}ineralogical control of organic carbon dynamics in a volcanic ash soil on {L}a {R}eunion},
  author = {{B}asile {D}oelsch, {I}sabelle and {A}mundson, {R}. and {S}tone, {W}.{E}.{E}. and {M}asiello, {C}.{A}. and {B}ottero, {J}ean-{Y}ves and {C}olin, {F}abrice and {M}asin, {F}. and {B}orschneck, {D}. and {M}eunier, {J}. {D}.},
  editor = {},
  language = {{ENG}},
  abstract = {{I}n soil carbon dynamics, the role of physicochemical interactions between organic matter and minerals is not well understood nor quantified. {T}his paper examines the interactions between soil organic matter and poorly crystalline aluminosilicates in a volcanic ash soil on {L}a {R}eunion in the southern tropics. {T}he soil examined is a profile composed of a surface soil ({L}-{A}o-{E}-{B}h) overlying four buried horizons (horizons 2{B}w, 3{B}w, 4{B}w, 5{B}w) that have all developed from successive tephra deposits. {N}on-destructive spectroscopy ({XRD}, {FTIR} and {NMR} of {S}i and {A}l) showed that the mineralogical composition varies from one buried horizon to another. {F}urther, we show that buried horizons characterized by large amounts of crystalline minerals (feldspars, gibbsite) have the least capacity to store organic matter and the fastest carbon turnover. {I}n contrast, buried horizons containing much poorly crystalline material (proto-imogolite and proto-imogolite allophane, denoted {LP}-{ITM}) store large amounts of organic matter which turns over very slowly. {T}o understand the mechanism of interactions between {LP}-{ITM} and organic matter better, we focused on a horizon formed exclusively of {LP}-{ITM}. {W}e demonstrate, using {D}elta(14){C} and delta(13){C} values, that even though {LP}-{ITM} is extraordinarily effective at stabilizing organic matter, {C} linked to {LP}-{ITM} is still in dynamic equilibrium with its environment and cycles slowly. {B}ased on {D}elta(14){C} values, we estimated the residence time of organic {C} as similar to 163 000 years for the most stabilized subhorizon, a value that is comparable to that for organic carbon stabilized in {H}awaiian volcanic soils. {H}owever, this calculation is likely to be biased by the presence of microcharcoal. {W}e characterized the organo-mineral binding between organic matter and {LP}-{ITM} by {A}l-27 {NMR}, and found that the organic matter is not only chelated to {LP}-{ITM}, but it may also limit the polymerization of mineral phases to a stage between proto-imogolite and proto-imogolite allophane. {O}ur results demonstrate the important role of poorly crystalline minerals in the storage of organic {C}, and show that mineral and organic compounds have to be studied simultaneously to understand the dynamics of organic {C} in the soil.},
  keywords = {},
  booktitle = {},
  journal = {{E}uropean {J}ournal of {S}oil {S}cience},
  volume = {56},
  numero = {6},
  pages = {689--703},
  ISSN = {1351-0754},
  year = {2005},
  DOI = {10.1111/j.1365-2389.2005.00703.x},
  URL = {https://www.documentation.ird.fr/hor/fdi:010036713},
}