Why is knowing the soil orders from the U.S. Soil Taxonomy important?
The soils belonging to the same soil order 1 share common characteristics. ENTISOLS and INCEPTISOLS, for instance, have poorly defined or weakly expressed horizons simply because the duration of soil development is very short. Some soils occur in special settings. VERTISOLS have large amounts of clays 3 that shrink when they dry and swell when they are wet while ANDISOLS form in volcanic deposits or HISTOSOLS form in the deep organic deposits found in peat bogs. Some soil orders occur in specific climate zones: ARIDISOLS in deserts and MOLLISOLS in grasslands. Forest ecosystems span humid climates ranging from cool to warm tropical. The sequence of soil orders found in humic forest ecosystems ranges from SPODOSOLS (cool), through ALFISOLS and ULTISOLS (temperate and warm subtropical) to OXISOLS (warm tropical). Simply knowing the soil order says volumes about the location and natural history of the soil.
