The last added soil order is

Based on chemical, physical and biological features, the soil has been categorized into 12 categories, which are called soil orders. These are Vertisols, spodosols, Mollisols, histosols, Entisols, Andisols, Ultisols, Oxisols, Inceptisols, Gelisols, Ardisols, Alfisols. Entisols are the pedologically youngest of the soils added to the order recently. It is formed from freshly deposited materials.