THE IMPORTANCE OF SOIL

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)

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

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

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

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)

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

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

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

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

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

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

SAND: particles larger than .05 millimeters

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

CLAY: particles smaller .002 millimeters

SAVING SOILS LAB PART 3 Part 3: Particle Size Distribution

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

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

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?

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.

COMPLETE SAVING SOILS LAB PART 3 FOLLOW PROCEDURE FOR DAY 2