@article{fdi:010040931,
  title = {{T}exture and sesquioxide effects on water-stable aggregates and organic matter in some tropical soils},
  author = {{B}arth{\`e}s, {B}ernard and {K}ouakoua, {E}. and {L}arr{\'e}-{L}arrouy, {M}arie-{C}hristine and {R}azafimbelo, {T}antely and de {L}uca, {E}.{F}. and {A}zontonde, {A}. and {N}eves, {C}.{S}.{V}.{J}. and de {F}reitas, {P}.{L}. and {F}eller, {C}hristian},
  editor = {},
  language = {{ENG}},
  abstract = {{M}any tropical soils include sesquioxides, which influence the stability of soil organic matter ({OM}) and aggregation to an extent that is not fully characterized. {T}he present study was carried out on a range of 18 topsoil samples (0-10 cm) from low-activity clay ({LAC}) soils from sub-{S}aharan {A}frica and {B}razil, and aimed: (i) at characterizing the size distributions of water-stable aggregates and organic constituents, (ii) at studying how these distributions were affected by texture and sesquioxides, and (iii) how they interacted. {T}he distributions of stable aggregates were generally dominated by macroaggregates (>200 mu m), and those of organic constituents by fine {OM} (<20 mu m). {A}ggregation was not clearly affected by soil texture, while total soil. carbon ({C}t) and the amount of carbon ({C}) as fine {OM} increased with soil content in clay plus fine silts (<20 mu m). {S}table macroaggregation correlated with {C}t and with {C} amount as fine {OM}, but each of them correlated more closely with citrate-bicarbonate-dithionite-extractable aluminium ({A}l), which was not expected. {S}table macroaggregation also correlated with {C} amounts as coarse- and medium-sized {OM} (> 200 and 20-200 mu m, respectively), but each of them correlated more closely with oxalate-extracted {A}l. {T}hese results suggested that for the {LAC} tropical soils under study {OM} and aggregate stability depended closely on {A}l-containing sesquioxides, on {A}l-substituted crystalline hematite and goethite especially. {T}hese sesquioxides also seemed to play a dominant role in the relations between aggregation and {OM}. {A}s far as soils rich in sesquioxides are concerned, this confirmed that {OM} is not the main aggregating agent, and suggested that physical protection within aggregates is not necessarily the main mechanism for {OM} stabilization. {H}owever, as soil sesquioxide content cannot be managed easily, the effect of land use on soil {OM} and aggregation was determinant at the local scale: indeed, for a given location, stable macroaggregation, {C}t and {C} amount as fine {OM} generally decreased with land use intensification (i.e. cultivation, tillage, reduced surface cover).},
  keywords = {},
  booktitle = {},
  journal = {{G}eoderma},
  volume = {143},
  numero = {1-2},
  pages = {14--25},
  ISSN = {0016-7061},
  year = {2008},
  DOI = {10.1016/j.geoderma.2007.10.003},
  URL = {https://www.documentation.ird.fr/hor/fdi:010040931},
}