Soil Horizons, Texture and Structure Topic 2054 Torey Birchmeier Brian Sobecki

Soil Horizons u3 Horizons v A Horizon v B Horizon v C Horizon

A Horizon uCommon names - Organic layer and top soil uTraits v Contains most plant roots v Heavily leached from heavy rainfall v Contains high organic matter v Dark in color

B Horizon uCommon name - Subsoil uTraits v Zone of acclimation ( Nutrients, silts and clays accumulate in this zone) v Little to No organic matter v Red and yellow in color

C Horizon uCommon name - Parent material uTraits v Below the root zone v Outside the Biological zone (Point were no plant or animals can grow or live)

Texture uDefinition: Percentage of sand, silt and clay particles v Size of particles.(largest to smallest) vSand vSilt vClay

Texture uWhy is texture Important? v Water absorption rates v Soil water storage capacity v Ease of tillage v Amount of aeration v Soil Fertility

Texture uDetermining Soil Texture By Feel v Sand Coarse gritty feel v Silt Medium-silty, floury feel v Clay Fine-sticky when wet

Structure uDefinition - the physical arrangement of soil particles v Structure affects the movement of water, air and root penetration

Structure uTypes of structures v Columns v Blocky v Granular v Plate-like

Structure uColumns v Water penetration-good v Drainage-good v Aeration-good

Structure uBlocky v Water Penetration-good v Drainage-moderate v Aeration-moderate

Structure uGranular v Water Penetration-good v Drainage-best v Aeration-best

Structure uPlate-like v Water Penetration-moderate v Drainage-moderate v Aeration-moderate

References §hpwww.gsfa.nasa.gov/globe/protocol/struct ure.htm § soil3125/doc/2chap3.htm