1. THE IMPORTANCE OF SOIL

2. WHAT IS SOIL MADE UP OF? IDEAL SOIL FOR THE ROOTS OF PLANTS CONTAINS:
50% SOLIDS
25% AIR
25% WATER
FOR SURVIVAL, PLANTS TAKE IN:
AIR (OXYGEN)
WATER (MOISTURE)
SOLIDS (NUTRITIONAL MINERALS)

3. How does soil help plants?
PLANTS NEED SUPPORT, OXYGEN, IONS, AND LIQUID TO SURVIVE.
SOME PLANTS CAN SURVIVE WITHOUT SOIL
AQUATIC PLANTS
HYDROPONIC PRODUCTION
Hydroponic production is a method of growing plants using mineral nutrient solutions in water without soil.
MOST PLANTS THAT HUMANITY DEPENDS ON FOR FOOD AND FIBER REQUIRE SOIL

4. How do soils form?
SOILS ARE FORMED BY SLOW WEATHERING PROCESSES THAT TAKE PLACE ABOVE AND BELOW THE EARTH’S SURFACE.
THERE ARE 3 TYPES OF WEATHERING
PHYSICAL WEATHERING
CHEMICAL WEATHERING
BIOLOGICAL WEATHERING

5. PHYSICAL WEATHERING PHYSICAL WEATHERING
Wind and rain blowing against mountains
Water washing small pieces of rock away
Freezing rain cracks smaller boulders into smaller rocks

6. CHEMICAL WEATHERING CHEMICAL WEATHERING (aka decomposition)
Rock chemically reacts with water and other acidic solutions to produce “rotten” rock that falls apart easier
Chemicals that are released during decomposition are sources of nutrients that help plants grow
Nitrogen (N)
Phosphorus (P)
Potassium (K)

7. BIOLOGICAL WEATHERING
LIVING ORGANISMS THAT CAUSE MECHAINCAL OR CHEMICAL WEATHERING
Tree roots
Lichen
Worms

8. SAVING SOILS LAB PART 1&2 Part 1: Mechanical Weathering
Part 2: Chemical Weathering

9. Soil horizons SOILS HAVE LAYERS CALLED “HORIZONS”
O HORIZON – LOOSE AND PARTLY DECAYED ORGANIC MATTER
Organic material is made up of living plants & animals, dead plants & organisms, and nutrients that have come from decomposed plants & animals
A HORIZON – MINERAL MATTER MIXED WITH HUMUS
B HORIZON – FINE CLAY PARTICLES
C HORIZON – PARTIALLY DECOMPOSED PIECES OF PARENT ROCK
FURTHER BELOW: UNWEATHERED PARENT ROCK

10. SOIL HORIZONS
DRAW THE HORIZON LAYERS OF SOIL AND LABEL THE CHARACTERISTICS OF EACH HORIZON

11. PRODUCTION OF FERTILE SOIL
LIVING WORMS & BACTERIA FEED ON DEAD ORGANISMS, MAKING THEM PART OF THE SOIL
HUMUS = DECAYED ORGANIC MATTER
HELPS KEEP SOIL MOIST BY SOAKING UP RAINWATER
REMOVES CHEMICALS AS RAIN SEEPS THROUGH
ROOTS CAN THEN ABSORB THESE NUTRIENTS
SOIL IS HOME FOR MANY LIVING ORGANISMS
Ants, beetles, grubs, spiders, mites, snails, worms, mice, shrews
THESE ANIMALS BURROW & TUNNEL MIXING AND BREAKING SOIL INTO TINY FRAGMENTS

12. Soil texture
In a sample of soil, the texture is determined by the ratio of sand, silt, and clay.

13. SAND: particles larger than .05 millimeters

14. silt
SILT: particles smaller than .05 millimeters and larger than .002 millimeters

15. CLAY: particles smaller .002 millimeters

16. SAVING SOILS LAB PART 3
Part 3: Particle Size Distribution

17. GOOD AFTERNOON! TODAY YOU WILL NEED: SIT WITH YOUR LAB GROUPS Ruler
Calculator
Pencil
Colored Marker or Pencil (not black or grey)
SIT WITH YOUR LAB GROUPS

18. OPENER
IN ORDER, RANK THE SIZE OF THE DIFFERENT TYPES OF SOIL (SILT, SAND, CLAY) FROM smallest TO LARGEST
CLAY < SILT < SAND

19. Did you know?
AN ACRE OF SOIL CAN HOLD ABOUT 5-10 TONS OF LIVING BEINGS?
About the mass of an elephant!
1 ton = 2000 pounds
SOIL CAN TAKE ABOUT 500 YEARS TO CREATE AN INCH OF TOP SOIL?
IF YOU TAKE 5 TONS OF SOIL AND SPREAD IT OVER AN ACRE OF LAND IT IS ONLY AS THICK AS A DIME?

20. 5 SOIL TYPES
EACH PERSON IN YOUR GROUP WILL READ ABOUT 2 OF THE 5 SOIL TYPES
UNDERLINE OR HIGHLIGHT THE ABJECTIVES AND QUALITIES THAT DESCRIBE EACH SOIL TYPE
ON A SEPARATE PIECE OF BLANK PAPER, CREATE A LIST OF THESE QUALITIES FOR EACH SOIL TYPE
SHARE AND COMPARE YOUR LISTS WITH YOUR GROUP MEMBERS SO YOU ALL HAVE A COMPREHENSIVE LIST OF THE QUALITIES OF EACH SOIL TYPE.

21. COMPLETE SAVING SOILS LAB PART 3
FOLLOW PROCEDURE FOR DAY 2