Can long-term fertilization accelerate pedogenesis? Depicting soil processes boosted by annual NPK-inputs since 1928 on bare loess Luvisol (INRAE-Versailles)

Human activities worldwide menace beneficial soil ecosystem services, but long-term anthropogenic impacts on properties and processes are often difficult to assess in field conditions. Here we exploited INRAE’s patrimonial ‘42-plots’ bare-fallow experiment, an unique long term experiment the world created 1928 Versailles (France), emphasize of annual inputs NPK fertilizers (ammonium, phosphate, potassium salts) basic amendments (lime, slag) loess Luvisols. We selected plots receiving monovalent (Na+, K+), acid (NH4+), (Ca2+) non-amended (reference) plots, thus embracing today widely diverging physicochemical surface soils Temporal changes characteristics were studied historical archived topsoil samples, whereas soil-depth samples from subsurface horizons collected 2015 until 120-cm depth. Bare-fallow management caused a rapid organic matter (OM) decay, acidification, CEC reduction lixiviation cations. With reduced OM-buffering capacities, specific fertilizer-induced conditions enhanced development several soil-forming processes. NH4-fertilizers amplified acidification (pH < 4), (i.e. 1.5 kg m?2 Ca), aluminization exchange complex, weathering ferromagnesian minerals plagioclase feldspars. Under (NH4)2HPO4 fertilization, quasi-total dissolution chlorite hornblende occurred, pointing acidocomplexolysis process which PO43- anion likely plays role complexing acids Podzols. Ammonium also affected E, B C horizons. In reference similar lower effects remained restricted horizon. Na/K-fertilizers favoured substantial clay translocation 10–15 m?2) Ap underlying E E/Bt Liming counteracted acidifying OM-depletion, raised pH 8–8.5 exchangeable Ca >95%. It may be clear that initial design specifications do not allow direct comparison with current agricultural soils. However, view global climate change, foreseeing lowering carbon contents soils, 42-plots trial acts like “alert launcher”, forecasting risks degradation respect mineral phases, parameters processes, generally buffered masked by presence matter. The forms high-valued playing for experimental research, offering centennial time-span differing context close pedogenetic connexion.