@article{fdi:010084738, title = {{P}rocesses and rates of formation defined by modelling in alkaline to acidic soil systems in {B}razilian {P}antanal wetland}, author = {{M}erdy, {P}. and {G}amrani, {M}. and {M}ontes, {C}. {R}. and {R}ezende, {A}. {T}. {R}. and {B}arbi{\'e}ro, {L}aurent and {I}shida, {D}. {A}. and {S}ilva, {A}. {R}. {C}. and {M}elfi, {A}. {J}. and {L}ucas, {Y}.}, editor = {}, language = {{ENG}}, abstract = {{W}ithin a soil system, it is generally difficult to relate the observed secondary phases and their spatial distribution to past or current processes. {G}eochemical modelling can help to identify present-days processes and to quantify formation rates if the system is sufficiently constrained. {H}ere we used the {PHREEQC} model for this purpose, applying it to soil alkaline to acidic soil systems in the {N}hecola<{SIC}>ndia area. {A} large amount of data was available, but scientific questions remained opened. {W}e carried out a complementary field study to clarify a key point necessary for modelling, confirming the disconnection between two types of groundwater, perched, alkaline and deep, acidic. {O}ur simulations showed that the observed soil system corresponds to the current biogeochemistry and that paleoclimatic genetic hypotheses are unnecessary. {W}e found that the ridge soil formation rate ranges from 396 to 638 kg ha-1 y-1, depending on hypotheses. {W}e showed that the downslope soils act as buffers to store labile species during the dry season, allowing alkalinity to be maintained from one year to the next. {A}t least 125 y were necessary to obtain downslope alkaline lakes, and this alkaline nature can quickly disappear after changing drainage conditions. {W}e explained how hyperacidic horizons (p{H} < 4) can neighbor alkaline horizons (p{H} > 10) with a sharp contact. {W}hen correctly informed, geochemical modelling appeared as an effective tool to answer questions about soil processes.}, keywords = {{S}oil formation rate ; {PHREEQC} model ; {S}aline and alkaline soils ; {S}oil p{H} change ; {W}etlands ; {BRESIL} ; {PANTANAL}}, booktitle = {}, journal = {{C}atena}, volume = {210}, numero = {}, pages = {105876 [12 ]}, ISSN = {0341-8162}, year = {2022}, DOI = {10.1016/j.catena.2021.105876}, URL = {https://www.documentation.ird.fr/hor/fdi:010084738}, }