In a soil, an aggregate of silt, sand, and clay of characteristic shape, resulting from the formation of hydrogen and ionic bonds between soil particles. Peds may be further developed by plant roots, by polysaccharide gums secreted by soil fauna (Piccolo and Mbagwu (1999) Soil Sci. Soc. Am. J. 63), and by alternate freezing and thawing, or wetting and drying (Hart et al. (1985) Eur. J. Soil Sci. 36, 3). Ped properties can be reflected in the structure of pore space (Pachepsky and Rawls (2003) Eur. J. Soil Sci. 54, 3).