Soil Characteristics and Genesis of Inceptisols with Placic horizon in subalpine Forests of Taiwan

Four pedons of Inceptisols with placic horizon were selected to investigate the soil characteristics, genesis, and classification of subalpine forest soils located in Shang-Hsing Mountain, northeastern Taiwan. Soils have cool and humid condition with very high precipitation (>3500 mm/yr), elevation ranged from 1700 to 2200m, coniferous vegetations, and gentle slope. Ultisol is only distributed in the level landscape position, but Inceptisol is typical soil distributed in the study area. The soil moisture regime is perudic and soil temperature regime is mesic. The selected four pedons can be classified as Lithic Dystrudept or Oxyaquic Dystrudept based on Soil Taxonomy system or Cambisol based on WRB system. We propose that a Placic Dystrudept should be included in the Subgroup of Dystrudepts in Soil Taxonomy system or a Placic Cambisol should be included in the Subgroup of Cambisols in the WRB system. Clear pedogenic processes were observed by the eluvial albic (E) horizon and the illuvial placic (Bs) horizon, which was characterized on the changes of soil color, texture, and chemical compositions. The depth of placic horizon of selected pedons ranged 2-5 mm. Because the parent materials of the studied soils are slate, the B horizon of studied pedons have unusually finer soil texture (>30 % clay). There are an abrupt soil texture change between E and cambic (Bw) horizon. In this environmental condition, the typical Spodosols were not easily developed