La collection historique d’échantillons de sols de l’essai patrimonial des ‘42 parcelles’ (INRAE, Versailles) : une machine à remonter le temps

Following three previous papers (van Oort et al., 2016, 2017, 2020) dealing with current soil characteristics and geochemical budgets in surface horizons, as well as the impacts of fertilization in subsurface horizons in soils of INRAE’s long term bare fallow experiment (the 42-plots trial), we now present some chronological aspects of soil evolution at the soil’s surface since 1928. For that, we analyzed several series of about 15 samples from the historical sample archive for 10 representative treatments: fertilizers with acidifying effects (ammonium sulphate, ammonium phosphate), fertilizers with dispersive effects (sodium nitrate, sylvinite, and potassium chloride), superphosphate, amendments with alkaline effects (basic slag, calcium carbonate), horse manure, as well as two reference plots, without inputs. We examined temporal evolutions of: i) edaphic parameters such as organic carbon and clay contents, pH, CEC and exchangeable cations; ii) total concentrations of major and trace elements; iii) the mineralogical composition of clay and fine silt fractions with a focus on the acidifying ammonium treatments. This work produced original findings on the magnitudes of pedogeochemical changes that occurred during the 90 years of the experiment. Regarding previous results on soil-depth impacts, our findings contribute at recounting complementary parts of a same history of soil development. constraint by different fertilization practices. From a pedological point of view, the 42-plots experiment acts as a “pedotron” under real climatic conditions, showing an acceleration of soil processes of the silt Luvisol following different pedological pathways as a function of the applied fertilizer or amendment. A la suite de travaux précédents sur les états pédogéochimiques, les bilans géochimiques et les impacts de la fertilisation dans les horizons profonds du NEOLUVISOL de lœss du dispositif des 42 parcelles d’INRAE (van Oort et al., 2016, 2017, 2020), nous examinons ici des aspects chronologiques d’évolutions intervenues en surface des sols depuis 1928. Pour cela, des séries d’une quinzaine d’échantillons de la collection historique ont été analysées pour une dizaine de traitements représentatifs : engrais à effet acidifiant (sulfate et phosphate d’ammonium), engrais à effet dispersant (nitrate de sodium, sylvinite, chlorure de potassium), superphosphate, amendements à effet alcalinisant (scories de déphosphoration, carbonate de calcium), fumier de cheval, ainsi q