The soil, though an often-overlooked component of the natural environment, yields many valuable benefits, helping to support biodiversity, acting as a reservoir for water, recycling nutrients, purifying groundwater, filtering out pollutants, and mitigating and adapting to climate change. The various benefits provided by soil are called soil ecosystem services, which in Korea are worth about 1,190 trillion won. Soil is also an important natural medium for supporting plant growth and crop production. Organic matter content is a key property associated with soil health, fertility, and water holding capacity. Soil carbon stock is an important indicator for evaluating the carbon balance of agricultural land and the global carbon balance.

 

 Korea’s soil distribution pattern is quite complex, due in part to the long history of intensive land use, diversified geological features, and rough terrain. Current classifications are generally made according to Soil Taxonomy, established by the United States Department of Agriculture (USDA), and based on soil physical and chemical properties. According to the Soil Taxonomy, out of the 14 orders of soil recognized globally, Korea has seven orders, 14 suborders, and 32 great groups of soils. In addition, approximately 400 soil series (the most detailed level of soil classification) have been identified to date. Inceptisols, soils lacking clear horizon development, cover 76.7% (7.21 million ha) of Korean territory. The predominance of Inceptisols indicates that the land surface has undergone dynamic changes. For instance, rapid soil erosion constantly removes topsoil from slope surfaces, with deposition in areas such as alluvial fans, valleys, and floodplains.

 

 Soil-forming factors such as microclimate, vegetation, topography, hydrology, geologic substrate, or weathering exposure times determine the spatial distribution of soil types in an area. These factors can affect the land's surface in a particular pattern for a given landscape, resulting in a somewhat predictable pattern in the spatial arrangement of soil types. The pattern of soils developed across a slope due to differences in substrate and hydrologic properties is called a soil catena. The illustration above depicts a sequence of soil types typically found across the Korean landscapes from granitic drainage divides downslope to floodplains. 

 

 Texture is perhaps the most important attribute of soils and controls many other physical and chemical characteristics of soil. Soil texture categories are determined by the relative proportion of three kinds of soil mineral particles: sand (0.05–2 mm), silt (0.002–0.05 mm), and clay (particles smaller than 0.002 mm). Soil textures are often plotted and visualized using the soil textural triangle, a ternary plot with three axes. 

 

 Recent environmental and climatic changes are bringing a greater awareness of the connection between soil and other elements of the environment, such as water quality and vegetation. To respond to increasing societal demands for detailed knowledge regarding soils, there is a need to better understand the spatial distribution and temporal changes of soil properties. In order to evaluate and manage soil quality and to sustain ecosystem services, it is necessary to understand the various properties of soils and how these relate to soil functions. In response to this, Korea conducts an extremely detailed and sophisticated soil survey, the results of which are made available to the public through a digitalized soil information system.