Reclassification of Korean Soils According to Revised Soil Taxonomy

Korean soils are classified officially by Soil Taxonomy.Soils in Korea were classified into 7 orders, 14 suborders, 27 great groups, and 390 soil series.The dominant soils in Korea were Inceptisols and Entisols, and Alfisols, Ultisols, Andisols, Mollisols, and Histosols were distributed to a small extent.This study was conducted to reclassify Korean soils based on the second edition of Soil Taxonomy: A Basic System of Soil Classification for Making and Interpreting Soil Surveys.Morphological properties of typifying pedons of 405 soils were investigated and physio-chemical properties were analyzed according to Soil Survey Laboratory Methods Manual of USDA.Alfisols of 44 soils were reclassified; 16 soils were reclassified as Ultisols and 3 soils as Mollisols.Forty Andisols were reclassified; 3 soils were reclassified as other orders.Sixty-four Entisols soils were reclassified; 11 soils were reclassified as Inceptisols, 4 soils as Mollisols, and 3 soils as Andisols.Two hundreds and ten Inceptisols soils were reclassified; 39 soils were reclassified as Alfisols, 21 soils as Ultisols, 13 soils as Mollisols, and 2 soils as Andisols.Twenty-one Inceptisols soils, 16 Alfisols soils, and one Andisols soil were reclassified as Ultisols.As a result of reclassification of Korean soils, Korean soils are now classified into 7 orders, 17 suborders, 39 great groups, 85 subgroups, and 405 soil series.Alfisols and Ultisols are increased remarkably.Sixty Inceptisols soils are reclassified as Alfisols or Ultisols; 44 soils including 30 paddy soils are distributed on fluvio-marine plains, alluvial plaines, local valleys, alluvial fans, and mountain foot slopes.Soils distributed on rolling to hilly areas are mainly developed as Ultisols and some are as Alfisols.Also soils distributed on diluvial terrace are mainly developed as Ultisols and some are as Alfisols.Only two Mollisols soils were developed to a small extent.But 15 soils in Jeju Island and Ulreung Island, 3 soils in limestone areas, and 5 soils in coastal areas are classified as Mollisols.Inceptisols occupied 76.6% and Entisols occupied 12.9% of the whole country.Ultisols and Alfisols occupied only 5.0% and 3.8% respectively.Many soils deveped on rolling to hilly, diluvial terraces, local valleys, mountain foot slopes, etc. are reclassified as Ultisols and Alfisols.As a result Ultisols occupy 12.9% and Alfisols occupy 8.8% of the whole country.