Naturalists at Large: Soil composition

4th Grade

Springville, Utah

Where does soil come from?

•Rocks•Minerals

•Organic Matter

oA

E

B

C

R

TOP SOIL

SUBSOIL

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 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

What are some practices

Of

SOIL CONSERVATION?

TerracingStrip Cropping

Contour PlowingTilling

Wind BreaksGround Covers

Internet Sites

• http://www.tx.nrcs.usda.gov/class/sammy.htm