Soils

medium for plant growth, regulator of water supplies, habitat for organisms/biota, public health, recycling/storage of raw minerals

additions (input organic matter), losses (erosion, decomposition), translocations (movement down), transformation (chemical/physical modifications of elements in soil)

chemical/physical alteration and reorganization of rocks and minerals 

parent material (original material), climate (temp/moisture), organisms/biota(vegetation, macro, micro) relief/topography (altitude, slope) time (controls extent of other factors)

the process of soil formation as the result of the combination of soil forming factors and processes

residual (formed in place from rocks and minerals), alluvial (deposited by rivers/streams), marine (oceans), eolian (wind), glacial (ice)

sandy marine/alluvial sediments which derived from clayey, silty sands

• water increases weathering rates and translocations
• heat increases rates of physicochemical processes

O (above mineral soil),A (surface mineral, accumulation of OM, weathered, elluvial, p sub),E (zone of loss),B (zone of accumulation of clays, OM, salts, iron, t,h,w,g sub),C (resembles parent material),R (bedrock)

a (sapric highly decomposed),e (hemic mod),i (fibric slightly),g (gleying-wet, low oxygen),h (OM),p (disturbed, plowed),t (clay),w (weak)

• hue-proportions of red and yellow
• value-reflected light
• chroma-strength of color

• sand 2.0-0.05mm
• silt 0.05-0.002mm
• clay less than 0.002mm

• primary dominate sand & silt, not ractive
• secondary dominate clay, very reactive

the total volume of pore space in a soil, indicates max volume of water and gasses a soil can hold (finer-textured soils have greater TP)

large particles yield large pores

• settling velocity of particles in a fluid
• V=KD2 (K=11,241)

• BD=mass OD soil/volume soilds+pores
• range 1.0-1.6 g/cm3
• 1-5& OM

PD=2.65g/cm3 (no pores)

• OM increases porosity, decreases BD
• compaction/depth decreases porosity, increases BD

• % porosity=[1-(BD/PD)]x100
• BD high------porosity low
• BD low------porosity high