Soil lab guiding questions

Soil v4
Importance, Formation, Properties & Nutrients
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Essential Question
Why is soil important to all living things?
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Key Soil Vocabulary
Soil Formation – creation of soil by breaking down rocks, minerals, & adding water, decaying plants, animals &
other once living creatures
Sand – Small loose grains of worn or disintegrated rock
Silt - Fine sand, clay, or other material carried by running water and deposited as a sediment.
Clay - fine-grained minerals; generally “plastic “ when wet & hardens when dried or fired.
Loam - A soil with proportions of sand, silt, clay & humus. (Equal parts of the 3 + 5-10% humus is most fertile.)
Nutrients – Chemicals organisms need to get from the environment to build new cells & make internal processes
work (like building DNA, digestion, make leaves). Key plant nutrients (NPK) :
Nitrogen (N)– helps plants have greener leaves, faster growth, better seed & root production
Phosphorous (P) - helps plant root growth, flower blooms. Makes plants grow faster with less stress
Potassium (K) - helps make stronger stalks & stems, gives drought resistance Less disease & insect damage
pH – measure of how acid or basic a soil or solution is. Acids have pH numbers from 0 to below 7, 0 is the
strongest acid. 7 Is pH neutral. Numbers, above 7 to 14 pH are basic, 14 is the strongest base.
Decomposition – process by which organic substances are broken down into a much simpler form of matter.
Matter Cycling - constant cycling of Earth’s atoms between living & nonliving parts of the environment.
Soil Erosion – constant wearing away (weathering) & transport of the top layers of the soil to valleys, rivers, & the
ocean
Organic Matter – matter from living or once living plants, animals and other creatures.
Inorganic Matter – matter not consisting of or deriving from living matter. Compounds lacking carbon.
Weathering – breakdown of the outer rocky part of the Earth into smaller particles like sand, clay & minerals. &
movement of particles to other places : There are three types:
Physical – breakdown of rock by wind blown sand, the freeze -thaw effect, and direct impact.
Chemical – breakdown of rock into smaller particles by contact with chemicals like water, acids & bases.
Biological – breakdown of rock/stone by plants, animals and microbes
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Vocabulary (continued)
Soil Layers or Horizons - 4 layers exist in the PacNW. Nutrients & water flows down through these layers to plant
roots. The rest flows down or sideways in the soil., enriching lower layers.
“O” layer (also “Litter” layer) – Top soil layer made of dead, decaying plants & animals. When decayed to
nutrient rich humus, becomes part of the A layer. Dark black/brown.
“A” Layer, or Horizon (also “Topsoil”) - Layer rich in nutrients, decaying material, & microorganisms. Darker
color.
“B” Layer, or Horizon – Less humus, nutrients & decaying material. Has more small rocks. Lighter in color..
“C” Layer, or Horizon – Rocky, low nutrients , big rocks, part of Earth’s outer layer. Lighter, bedrock color.
Humus - A dark, organic material formed in soil when plant & animal matter decays.
Soil organisms – Microorganisms are bacteria, fungi & tiny creatures called protozoa. Macro organisms include
worms, insects, moles, shrews, etc.
Physical properties - structural characteristics of soil. Example: Texture, Clumping, Water holding ability….
Biological properties - the amount of decomposers in soil Example: Bacteria and Fungi
Chemical properties – type/amount of chemicals in soil. Macronutrients (NPK) & Micronutrients (Calcium, Zinc,
H2O) & proper pH
Soil Erosion – breaking down soil structure & moving the particles away. (Cause: Water, Wind, Ice, Gravity)
Overgrazing - soil/plants exposed to intensive grazing for long periods of time, or without enough recovery
periods
Soil Pollution/Contamination – presence of human made chemicals, farm & industrial waste products.
Soil Sealing – Covering soil by roads, houses, parking lots so as to not allow forests or crops to grow.
Dead Zone – an area of a lake, sound or ocean with very low, or no, oxygen, causing marine life to die. Often
caused by run off of high nutrient soil, fertilizers, animal wastes, or contrary winds etc.
Results – the statement(s) that explains or interprets data from an investigation.
Field Study - collecting data outside of a lab setting. Done in natural settings or environments and can be done in
a variety of ways for various disciplines.
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What was the Dust Bowl?
Dust Bowl Video http://www.youtube.com/watch?v=1_nG9LX0Ioo&feature=related
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What Caused the “Dust Bowl”?
• US gives each settler 4x more
land to farm
• Unusual wet weather caused
settlers to think area is good
for intense cultivation
• 6x more area becomes
farmed
• Native grasses holding soil
were removed
• Severe drought strikes in
1930’s, not abnormal…
• Wind, dried topsoil, creates
huge dust storms
Result - Massive erosion!
jschmied©2015

Effects of the Dust Bowl 1930-1940
Human Health : 1. Dust seeped in cracks & crevices, covering everything.
2. Hundreds of patients contracted "dust pneumonia."
3. Farmers became lost in their own field, suffocated.
Massive loss of Topsoil: In 1934 two storms alone blew 650 million
tons of topsoil off the Great Plains.
Agriculture: Crops buried, in the worst hit areas farming ceased.
Livestock Losses: Livestock suffocated. Cattle ate the dust- laden grass
& filled their stomachs with fatal "mud balls."
Loss of Property: Dust covered houses, buried fences & filled farm
buildings. Penetrated auto engines clogging parts.
Population: Over 350,000 people fled the Great Plains in the 1930s.
jschmied©2015
http://www.encyclopedia.com/topic/Dust_Bowl.aspx

Some solutions to Dust Bowl Problems…
Some areas have NEVER RECOVERED
Contour Farming Planting Windbreaks
Replanting Native Grasses Providing Farmers Expert Help
jschmied©2015

What is Weathering?
Weathering
The breakdown of the
outer rocky part of the Earth
into smaller particles like
sand, clay & minerals.
Includes the movement of
particles to other places
Three types:
• Physical
• Chemical
• Biological
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Rock makes up the outermost layer of Earth
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Physical (mechanical) Weathering
The breakdown of rocks by physical processes
with no change in the new rock’s make up.
Creates joints in rocks
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Chemical Weathering
is the breakdown of rocks caused by a change in the rock’s chemical make up
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1. Oxygen reacting
with minerals
2. CO2 & H20
makes
Carbonic acid
which reacts
with minerals
3. H20 reacts with
minerals directly
Some Types

Biological Weathering
the weakening & breakdown of rock by plants, animals and microbes.
Plant Roots - exert stress or
pressure on rock. This is a biologically
caused physical action.
A Lichen is made of a
fungi & an algae. The
Fungi release chemicals,
breaking down rock
minerals. The minerals
released from rock are
consumed by the algae.
Plant roots or microorganisms
produce organic acids which help to
dissolve minerals.
jschmied©2015
Burrowing animals
…bore into rocks
for protection
either by scraping
away the grains or
secreting acid to
dissolve the rock.

Processes in the Rock Cycle
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Visit this site
and research
Weathering.

Soil Composition & Formation
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Soil Development over time
The development of a soil is influenced by five interrelated
factors: 1. organisms 2. topography 3. time 4. parent
material, and 5. climate.
(Source: PhysicalGeography.net)
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Soil Composition
Figure 1: Most soils contain four basic components:
Mineral particles, water, air, and organic matter.
Organic matter can be further sub-divided into humus,
roots, and living organisms.
Values given are for an average soil. (Source: PhysicalGeography.net)
jschmied©2015
Air, Water &
Minerals are
Inorganic
Matter!

Soil Types by particle size
The three main soil types.
Sand
Small rock &
mineral
particles
0.5 – 2 mm
(500 – 2000)
microns
Silt
Fine sand,
clay, minerals
carried by
running
water &
deposited as
sediment
2 – 50
microns
Clay
Very Small
minerals
< 2
microns
Different mixes of the three
soil textures make soil with
different characteristics
Micron = 0.00004 inch!
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Soil Formation
Weathering
• Physical, Chemical and
Biological processes break
down rock.
Erosion
• Broken down rock is
moved by wind, water, or
ice. This breaks the rock
down more!
Deposition
• Plants grow.
• Organic material
added
• Humus forms
• Soil layers form
jschmied©2015

Humus brings soil to life!
• A dark, organic material
formed in soil when plant &
animal matter decays.
• Contains nutrients (minerals
such as, nitrates, phosphates,
potassium, copper, zinc
dissolved in water) plants
need to be healthy.
• Improves the fertility & water
retention of soil
Humus can be:
• produced naturally
• by composting.
Humus must be added to soil to
make plants thrive.
A fertile soil should contain at least 5% organic matter, 4% of which is humus.
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Different mixes of the three soil types make soil
with different characteristics
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A fertile soil
should contain
at least 2 - 8
percent organic
matter.

Formed from broken down rocks and minerals mixed with
decaying plants and animals. (Plus H2O & Air)
Soil created by:
• Physical, chemical & biological weathering of rocks
into sand, silt & clay.
• Microorganisms breaking down
organic matter to humus .
Summary: Where does soil come from?
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So soil is a mixture of inorganic
and organic matter.
• Organisms living in soil recycle
& store nutrients, making
the soil more fertile over time.

• Soil Nutrients wash into sea & fertilize oceanic
phytoplankton.
– Phytoplankton are the basis of all oceanic food chains
& make about 70% of the worlds oxygen!
6 ways soil is important to all living things
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• Is a growing medium for plant (food) production
Plants provide food and oxygen for animals
• Is habitat for billions of animals & decomposers
• Filters water, controls water flow & stores water
• Recycles nutrients, absorbs & neutralizes contaminants
• Provides most antibiotics used to fight diseases

Properties of Soil
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Physical Properties of Soil
Soil needs the proper combination of 3 key
properties to support life.
Physical, Chemical & Biological
Physical properties have to do with soil’s structural characteristics.
http://www.fao.org/soils-portal/soil-survey/soil-properties/physical-properties/en/
Key Characteristics:
• Structure = % Sand, Silt & Clay
• Texture = Size of grains in the sample, also % organics
• Clumping Ability = Ability to stick together
• Water holding ability & availability of water = for plants
• Color = Tells boundaries in soil profiles
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Water Flow in soil grains
• Micropores between soil particles hold water
• Macropores allow water to flow between particles
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Chemical Properties of Soil
Key chemical properties:
http://www.fao.org/soils-portal/soil-survey/soil-properties/chemical-properties/en/
- Proper soil pH = (Acid – Base balance)
- Chemical nutrients – 2 types. (16 total nutrients of healthy soil)
Macronutrients => needed in larger amounts.
Nitrogen (N), Phosphorus (P), Potassium (K), Carbon (C), Oxygen (O), Hydrogen (H),
and Calcium (Ca), Magnesium (Mg), Sulfur (S). Essential nutrients to plant
development.
Micronutrients => needed in smaller amounts, but also crucial for plant
development and growth. Iron (Fe), Zinc (Zn), Manganese (Mn), Boron (B), Copper
(Cu), Molybdenum (Mo) and Chlorine (Cl).
jschmied©2015

Biological Properties include the type & number of organisms
http://www.fao.org/soils-portal/soil-survey/soil-properties/biological-properties/en/
• Organisms include: fungi, earthworms, nematodes, protozoa, bacteria and different
arthropods (insects, spiders, millipedes, etc.) Fungi are key in PacNW soil.
• The organisms = break down organic matter => make nutrients available for uptake
by plants.
• Nutrients stored in the bodies of soil organisms prevent nutrient loss by leaching.
• Microbes maintain soil structure while organisms like earthworms are important in
reworking the soil.
• Bacteria play a vital role in the Nitrogen and Carbon cycles = getting & releasing
valuable macronutrients into the soil.
Biological Properties of Soil
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What are hazards
to healthy soil?
Erosion
Pollution
Soil Sealing
Cutting down forests
Poor Farming Practices
Overgrazing
Construction
Hazards “degrade” soil fertility.
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Extent of Eroded soil Worldwide
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Soil Erosion - a global problem
Erosion always happens. We have increased the process by poor land use!
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Erosion - Cutting down forests
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Erosion - Poor Farming Practices
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Soil Sealing
Covering soil w/roads, houses, malls, parking lots….etc.
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Erosion - Overgrazing
Too many animals eating the vegetation!
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Erosion - Construction
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“Dead Zone Process.
Forming a Dead Zone
Normal situation
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Aquatic Dead Zones
Low to no Oxygen Water meets oxygen rich waters in the Gulf of Mexico
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How does NW Washington forest soil lose
key nutrients like NPK?
http://static.ddmcdn.com/gif/deforestation-2.jpg
http://www.turf2max.com/Soil%20Restoration/how-to-prevent-soil-erosion_files/erosion_run_off.jpg
http://www.cob.org/services/environment/restoration/images/himalayan-blackberry.jpg
4. Invasive species
1. Rainfall
2. Deforestation
3. Soil Erosion by wind and water
http://leidorf.blogspot.com/2007/08/forest-with-fog.html
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Steps in forming soil & soil layers
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It takes a long time to make soil - > can take over 500 years to make 2 centimeters!

What are the layers in healthy soil?
• This is a cut away of a
Grassland soil. It
shows the different
soil horizons, or layers.
• The most “evolved
layer”, is the A
horizon, or “Topsoil”.
• There are 4 soil
horizons on top of
bedrock in this image,
layers O, A, B & C.
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Older Forests
develop an
“E” layer
between the
A & B layers.

Soil Fertility vs. Layers
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Most nutrients – most evolved
Least nutrients – least evolved
The most “evolved”
(broken down) layers
are the most fertile.
Thus the C layer is
less fertile than the
A layer.

What nutrients does
healthy soil need?
pH = Acid – Base balance
Plants need the correct soil
pH so the plant can take up
a nutrient.
jschmied©2015
Key Macronutrients:
Nitrogen (N),
Phosphorous (P)
Potassium (K)
Key Micronutrients:
Sulfur (S)
Magnesium (Mg)
Calcium (Ca)
Iron (Fe)
Zinc (Zn)
Manganese (Mn)
Molybdenum (Mo)
Copper (Cu)
Boron (B)

What do the macronutrients in soil do?
Leaf
Root
Stem
pHNitrogen
Phosphorous
Potassium
Nutrients – Chemicals
organisms need to get from
the environment, to build
new cells & make internal
processes work (like
building DNA, digestion,
make leaves).
jschmied©2015

Potassium (K) “Stem”
Increases fruit set
Stronger stalks &
stems
Drought resistance
Less disease & insect
damage
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pH and Nutrient uptake
Adjusting soil pH levels
is important because:
1. Specific plants grow
best in a certain range
of pH,
2. The correct soil pH
allow plants to take
up a certain nutrient.
3. If the pH is not
proper, the nutrient
can’t be taken in by
plant roots.
4. Soil pH influences the
amount of microbial
activity in soils. pH of
6->7 is best..
This figure shows the relationship between pH and
the availability of elements needed for plant growth
jschmied©2015

pH
How does this affect our Washington plants & forests?
– The PacNW rainfall & decomposition of leaves & needles
makes our soil acidic. Only certain plants can stand acidic soils.
– Conifers (pines, firs, cedars) grow best in acidic soils, that’s why
we have mostly conifers in the Pac NW!
– Our garden soils need to be adjusted to make the pH less acid.
jschmied©2015

Fertilizers have different amounts of NPK
You can tell the % of each nutrient on the bag!
This fertilizer has
5% Nitrogen
8% Phosphorus
4% Potassium
Organic fertilizer is better
for our planet overall.
It is a Trade Off though….
• On one hand it costs more!
• On the other hand
manufactured fertilizers make
the soil acid etc.
jschmied©2015

How do forest plants
get nutrients?
Leaf litter, animals,
debris die & fall to
forest floor
Fungi decay leaf litter, &
bacteria the animals (in
PacNW)
Nutrients released (
lower pH)
Nutrients dissolve in
water, are absorbed by
roots, leaving soil
nutrient poor
http://www.sustland.umn.edu/implement/images/planting_fig1a.gif
CO2
O2 Sunlight
NPK + H20
Water
Water
Nutrients
to tree
Nutrients
to soil
NPK & Water
Soil pH
Thermal
Energy
jschmied©2015

CO2
O2 Sunlight
NPK + H20
Water
Water
Nutrients
to tree
Nutrients
to soil
NPK & Water
Soil pH
Plants take up nutrients fast. Rain
washes the remaining nutrients out of
the soil, lowering soil pH.
Decaying plants & animals add
Nitrogen, Phosphorous & Potassium
back into the soil.
Not enough to replace all nutrients.
Phosphorous & Potassium
come from the weathering of rocks &
minerals in the soil to help
But the Nitrogen supply is limited
in PacNW.
Fungi is the primary NW decomposer
releasing nitrogen. 2nd Plants “fix”
some nitrogen in plant root nodules.
PacNW forest plants take up available
nitrogen fast, leaving our soil nitrogen
poor.
Thermal
Energy
jschmied©2015

Average Class Soil Test Data 2014
Data Table 1. Testing results for soil samples for Period XX
Test A Horizon B Horizon Potting Soil Garden Soil
Soil pH
[ 4 - 9 ] 4.5 4.5 7.5 7.5
Nitrogen (N)
[ Low-High ] low low low low
Phosphorous (P)
[ Low-High ] low low med med
Potassium (K)
[ Low-High ] high
medium-
high high high
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Plants vs Humans most common Element needs
Plants Humans
Element Element
Carbon Carbon
Hydrogen Hydrogen
Oxygen Oxygen
Nitrogen Nitrogen
Phosphorous Phosphorous
Sulfur
Potassium
Sulfur
http://www.mii.org/periodic/lifeelement.html
http://www.sciencelearn.org.nz/Contexts/Just-Elemental/Science-Ideas-and-Concepts/The-essential-elements
http://www.ncagr.gov/cyber/kidswrld/plant/nutrient.htm jschmied©2015

About the author:
John Schmied has been a secondary science school teacher for 20 years and is involved in developing
practical, yet innovative, hands on curriculum for teens. In addition he is a Chemical Hygiene Officer
and an Environmental Educator. He has created, developed and manages a 6 acre Environmental
Center at his school site.
John’s presentations are viewed worldwide & have been in the
top 5% of Slideshare for multiple years.
During this time John served as the Strategic planner for the
Friends of the Hidden River a 501(C)(3) non profit.
• Over the past 13 years Friends helped King County, WA
design, fund, construct & develop the 14,800 sqft
Brightwater Environmental Center in Woodinville WA.
• John is the Director & a principal developer of the Ground
to Sound STEM Environmental Challenge course, a locally
popular cutting edge environmental program that merges,
Science, Tech, Art, Multimedia and other disciplines with
Leadership studies at the Center
Prior to this period John served as a Coast Guard Officer,
primarily involved in ice, navigation & search and rescue
operations. His specialties are Ship handling, Diving and
Oceanographic Operations.
John can be contacted via Linked In.

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