Chapter 10: Soils and the infillings of the mountain poljes

Résumé - Abstract - Zusammenfassung:The sediments trapped in mountainous poljes of Hubei province are excellent recordings of the environment during Quaternary, Holocene and Historical ages. Examples of small poljes were studied in the Yanziping area (Datchangmi) and Datiankeng Polje of Hefeng County. In the former, one can see 10 to 25 m of fillings. A brown banded main layer (containing charcoal) overlies a fluvial terrace with boulders. Above Hefeng city, the Datiankeng polje (900 m a.s.l.) has a similar infilling. In both cases the annual summer flooding of the polje are recorded by deposits. The study aims to distinguish the influences by climate and man for the hydrology, soil erosion and forest degration, which is indicated by charcoals. A complementary study of the soils found in the poljes, depressions and within the cone karst, records historical changes associated with agriculture.

Keywords: Karst, polje, infilling, soil, erosion, forest degration, Holocene, farming history, mountain, climate, social crisis.