Soil classificationSoil classification involves systematically analyzing the characteristics and relationships of soils to classify them into common groups for effective soil managementSoil management. There are two primary soil classificationSoil classification systems used worldwide: The Soil Taxonomy system of the United States and the World Reference Base for Soil Resources (WRB) of the FAO. The classification system of Soil Taxonomy begins with 12 orders. In Korea, soils have been classified into 7 orders, 14 suborders, and 405 soil seriesSoil series. The seven orders are AlfisolsAlfisols, AndisolsAndisols, EntisolsEntisols, HistosolsHistosols, InceptisolsInceptisols, Mollisols,Mollisolsand UltisolsUltisols. Alfisols are primarily found in alluvial plains and on gently sloping hills and mountainous areas. They are classified into the suborders Aqualfs and Udalfs. Andisols are soils developed from volcanic ash materials, while Entisols are soils that lack a well-defined layer of development, often found on steep slopes or in newly formed alluvium, and are classified into the suborders Aquents, Psamments, Fluvents, and Orthents. Histosols are organic soils classified in the subphylum of Saprists and Hemists. Inceptisols are young soils that have just begun to develop soil layers. They are the most common in Korea and are classified into the Aquepts and Udepts suborders. Mollisols are dark-colored, base-rich, mineral soils typically found in grassland areas, classified in the suborder Udolls. Ultisols are strongly acidic soils with clay aggregates and low base saturation, classified into the suborders Udults and Humults.