Soilscape of west-central Taiwan: Its pedogenesis and geomorphic implications

•W. central Taiwan soilscape is characterised by soil and landform diversity.•Soil chronosequence Entisol → Inceptisol (Endoaquept)→ reddish Inceptisol (Dystrudept)→ Ultisol → Oxisol with time constraints.•Using weighted profile development index (WPDI) to assess the progressive pathway of soil development.•Relationship between soil distribution and soil genesis illustrates the paleo-environment of the fluvial system in the area.

Five different soil types, including Entisol, Inceptisol, Alfisol, Ultisol and Oxisol, are distributed across west-central Taiwan. These soils cover the surfaces of three geological terrains, namely, the Pleistocene anticline, the Holocene coastal plain, and the modern alluvial fan. These soils developed from the similar parent materials, facilitating the analysis of soil diversity and the processes of pedogenesis. The soil chronosequence of Entisol → Inceptisol (Endoaquept) → reddish Inceptisol (Dystrudept) → Ultisol → Oxisol with increasing age is suggested for the progressive pathway of soil development. The degree of pedogenesis was quantified using a weighted profile development index (WPDI), which indicates that the soils from the tropics develop faster than those in temperate and/or Mediterranean climates, but was not as fast as those documented in the published literature. Moreover, the distribution of soils during pedogenesis conformed to the order of landform formation. Soil genesis and the way in which the different soils evolve illustrate the paleo-environments of the fluvial system in the area.