Climate and soil moisture content during development of the first palaeosol in the southern Loess Plateau

Abstract

Summary The scientific problems concerning Quaternary soil water content and the water cycle have not been researched. This study examined the soil water content and depth of distribution of gravitational water in the south Loess Plateau during development of the first palaeosol layer (S1) by methods such as field investigation, electron microscopy, energy spectrum analysis, chemical analysis, and so on. The purpose was to reveal the climate, water balance and vegetation type at the time when S1 developed. The depth of migration of CaCO3 and Sr were 4.2 m below the upper boundary of the S1 palaeosol, and the depth of weathered loess beneath the argillic horizon was 4.0 m. Ferri‐argillans developed well in the argillic horizon and their depth of migration was 1 m below the argillic horizon. These findings suggest that the climate during the last interglacial was subtropical and humid, and the soil‐water balance was positive. Gravitational water was present to a depth of least 4.2 m from the top of S1, and the water content was adequate for tree growth. The chemical weathering index showed that this palaeosol has been moderately weathered. Highlights We studied the palaeo-water content index during development of the first palaeosol. Soil water balance during development of S1 palaeosol in the south Loess plateau was positive. Available water content was 14% during development of S1 palaeosol. We suggest that a subtropical climate and forest vegetation prevailed.

Climate Change and Vegetation Evolution during the Transition from Marine Isotope Stage 5 to 4 Based on Two Typical Profiles at the Southern Chinese Loess Plateau

“…It is noticeable that the extreme values do not exactly correspond to 76.8 ka B.P., as the transition from PZ-I to PZ-II occurred at about 76.5 ka B.P., and lagged several hundred years after the cooling event. This result approximately agrees with a number of previous studies [49,50].…”

Effects of Climatic Change on Soil Hydraulic Properties during the Last Interglacial Period: Two Case Studies of the Southern Chinese Loess Plateau

“…The soil water conditions can also be expressed by chemical elements [14]. In the southern CLP, the red ferri-argillans and migration of CaCO 3 and S r of S1 indicated that the paleo-climate of the last interglacial was subtropical and humid and the soil water balance was positive [15]. These results confirmed that S1 is appropriate for studying the effect of climate on pedogenesis and soil hydraulic properties.…”

“…During the pedogenic processes, soil systems stored large amount of information about environmental factors. Such as red ferri-argillans and Sr contents, these proxies revealed that in the southern CLP, the soil water balance was positive during the last interglacial, and the southern CLP was under a humid subtropical paleoclimate [15]. This mechanism was named "soil memory" [49].…”