Insoil science,peds are aggregates ofsoil particles formed naturally as a result ofpedogenic processes; this natural organization of particles forms discrete units separated bypores or voids. The term is generally used formacroscopic (visible; i.e. greater than 1 mm in size) structural units when observing soils in the field. Soil peds should be described when the soil is dry or slightly moist, as they can be difficult to distinguish when wet.[1]An artificially formed aggregate of soil particles can be called aclod.[2]
There are five major classes ofmacrostructure seen in soils: platy, prismatic, columnar,granular, and blocky. There are also structureless conditions. Some soils have simple structure, each unit being an entity without component smaller units. Others have compound structure, in which large units are composed of smaller units separated by persistent planes of weakness.