June 30, 2022
10h
Merc04
Paleosols, developed under the influence of past environmental conditions, are considerably valuable archives of past environments and soil formation. The Chinese Loess Plateau has a vertical alternation of Aeolian sediment (loess) and paleosols formed therein. These paleosols were formed during the interglacials, including the Quaternary. This thesis investigates how the expression of these paleosols can be related to the climatic conditions at the time of their formation. To this end, a climate model (LOVECLIM1.3) is linked to a soil formation model (SoilGen2). The climate model was corrected for bias, and the soil model was calibrated for various soil process parameters by confronting simulated and measured soil properties for interglacial soils formed in the CLP and test the effect of reconstructed dust addition patterns on soil development in the Loess Plateau. The results suggest that the calibrated soil model permits interglacial soil simulation in the CLP over long timescales. Subsequently, the response of the soil model to aspects of the simulated climate was determined for MIS 11 and MIS 13 interglacials. Results show that precipitation, Aeolian matter addition and potential evapotranspiration have the greatest impact on paleosols during MIS 11 and MIS 13 interglacials, but their relative importance varies between soil properties (e.g. mass of clay and calcite) and between interglacials. In addition, the response to orbital forced rhythms (precession) and to the NH ice volume during the interglacials was also investigated. Precession and NH ice volume both have indirect effects on paleosol formation through annual mean precipitation. Finally, the soil-climate model was used to quantify soil stocks and ecosystem services as a function of various low (natural) erosion rates. Results showed a negative performance of ecosystem services above 1.0 Mg ha-1 y-1 erosion rate as a threshold to the studied (semi-arid, monsoon) climate evolution.