where does soil come from? rocks minerals organic matter
TRANSCRIPT
Where does soil come from?
•Rocks•Minerals
•Organic Matter
Soil Properties
• Color – depends on organic matter and chemicals
• Texture – mixture of sizes of particles• Structure – arrangement of soil particles• Consistency – combo of texture and
structure• Porosity – loose or tightly packed
together?• Moisture – percentage of water content• Chemistry – N, O, CO2
Soil Horizons
• Run parallel to the earth’s surface and has characteristics different from horizons directly above or below.
oA
E
B
C
R
TOP SOIL
SUBSOIL
• O – “Organic” (plant & animal matter); dark in color; retains water and nutrients
• A – organic & clay; dark in color• E – “Eluviation” (minerals removed by
water seepage); coarse sand & silt; light in color
• B – clay; aluminum & iron; red/yellow from deposited minerals
• C – weathered bedrock• R – “Rock,” many different colors; no
nutrients
Sagebrush-Cold Desert
What are the main components of soil?
• Mineral Matter• Air
• Water• Organic Matter
SOIL COMPONENTSidealized soil
SOIL SOLIDS
WATER FILLED PORES
AIR FILLED PORES
50 %
25 %
25%
Soil Components (volume basis)
Note: clays are microscopic in size !
Soil separate particle diameter (mm)____________________________
Sand . . . . . . . . . 2.0 - 0.05
Silt . . . . . . . . . . 0.05 - 0.002
Clay . . . . . . . . . . <0.002
SAND
SILT CLAY
Clay mineralsphotographedwith an electronMicroscope.
Note: they are plateor flake like andare stacked on topof each other.
They are electricallycharged and act likemagnets that attractand hold plantnutrients.
What causes soil erosion?
WaterWind
No Vegetation
How did the Canyon Lands of Utah form?
What are some practices
Of
SOIL CONSERVATION?
TerracingStrip Cropping
Contour PlowingTilling
Wind BreaksGround Covers
What are the FACTORSthat make SOIL?
TIME1000’S TO 10,000’S OF YEARS
LAY OF THE LANDTOPOGRAPHY
LIVING ORGANISMSANIMALS AND PLANTS
CLIMATEHOT/COLD, WIND/RAIN
PARENT MATERIALROCKS AND MINERALS
Physical land features