SUB-ALPINE LOAMY SPODOSOLS IN TAIWAN - CHARACTERISTICS, MICROMORPHOLOGY, AND GENESIS

Four subalpine loamy Spodosols,vith illuvial clay in the spodic horizo ns were selected for study to understand their characteristics, microm orphology, and genesis. These Spodosols, located in central Taiwan, ar e covered by coniferous vegetation, receive high levels of precipitati on, and occupy gentle slope positions at elevations >2400 m. Soil text ures, which range from loam to clay, are finer than those of Spodosols formed in temperate regions. The pedogenic products in the soils of t he study area are mainly organo-metallic complexes or illuvial clay mi xed with organo-metallic complexes in the spodic horizons. Typical mic romorphological features in the spodic horizons of these Spodosols rev ealed infillings of organo-Fe complexes, argillans, or argiferrans alo ng the irregular voids. The four selected pedons have loose spodic hor izons where illuvial clay also has accumulated. The large amounts of s podic materials and illuvial clays in the spodic horizons indicate tha t podzolization and clay accumulation were the two dominant pedogenic processes. Some of the illuvial clay translocated into the spodic hori zons is mixed with organo-Fe (or -Al) complexes along the irregular vo ids of the spodic horizons. This may also have resulted in a lack of w ell-oriented clay in these horizons despite the occurrence of large am ounts of illuviated clays.