Download Introduction to Horizontation in Soils - Study Guide | CSES 3124 and more Study notes Environmental Science in PDF only on Docsity! Horizonation Prefix: Numbers are used to designate parent material changes (1 is implied – start numbering at 2) Master: A – Organic matter darkened surface soil E – A lighter color horizon which contains “clean washed” sand, silt and clay B – A horizon where subsurface “pedogenesis” has created structure and the illuviation of clays, oxides or organic matter C – A horizon with no evidence of “pedogenesis” (ie no structure, clay films and not redder) R – Rock that is strongly cemented Subhorizon : b – buried / w –development of some color or structure / t – presence of clay films p ‐ plowed / r – saprolite / h – illuviation of organic matter / s – illuviation o f oxides No.: Numbers are used to designate Master/Subhorizon combinations that repeat Boundary Distinctness: a – abrupt (changes within 2 cm) c – clear (changes within 6 cm) g – gradual (changes within 12 cm) d – diffuse (changes not visible within a 12 cm distance) Texture: abbreviations Sand S Loam L Silt SI Loamy sand LS Clay loam CL Silt loam SIL Sandy loam SL Clay C Silty clay loam SICL Sandy clay loam SCL Silty clay SIC Sandy clay SC Structure: Type‐ Grade‐ Granular GR Structureless SLS Subangular blocky/ Angular blocky SBK/ABK Weak WK Columnar/Prismatic CO/PR Moderate MO Massive MA Strong ST Single Grain SG Epipedon: Mollic – 3/3 or darker and over 25 cm thick and base saturation over 50% Umbric – 3/3 or darker and over 25 cm thick and base saturation under 50% Ochric – lighter than 3/3 or not 25 cm thick Histic – organic material at least 20 cm thick Order: Entisol – no B horizon Inceptisol – has Bw Alfisol – has a Bt horizon and has a base saturation in the lowest horizon over 35% Ultisol – has a Bt horizon and has a base saturation in the lowest horizon under 35% Spodosol – has a Bh or BS or Bhs horizon Mollisol – has a mollic epipedon and all horizons have a base saturation over 50 % Histisol – has a histic epipedon