1. SOIL PROPERTIES A crash course in soils Wednesday, November 5
Take out paper for Cornell notes!
SOIL PROPERTIES A crash course in soils Wednesday, November 5

2. And remember…
Red text on top = Header Black text = notes for you to copy OR paraphrase/ summarize Grey text = Liu’s talking points, no need to copy it down Underlined words = Important vocab

3. What are some soil properties?
Texture Permeability Porosity pH Nutrient Levels—Nitrogen/Phosphorus/Potash

4. SOIL TEXTURE Soil texture: The way a soil "feels"
Depends on the percentage of each size of particle in the soil
Sand, silt, and clay are names that describe the size of individual particles in the soil.
SAND are the largest particles and they feel "gritty.“
SILT are medium sized, and they feel soft, silky or "floury"
CLAY are the smallest sized particles, and they feel "sticky" and they are hard to squeeze.

5. Physical Property: Texture
Texture determines the type of soil, and the soil’s properties.
Loam: ideal for agricultural soil

6. Why care about soil texture?
Predicts soil properties-fertility, etc.
Sandy soils
low organic matter
Poor retention water and nutrients (it flows through)
As silt and clay fractions increase, soils
More organic matter
Better buffered
Better retention of water and nutrients
But you can have TOO much clay
Hard to cultivate-too sticky when wet; too hard when dry
Shrinks and swells
The best soils are a mix of all three and are called LOAM

7. Physical: Porosity & Permeability
Definition:
amount of pore spaces in soil (aeration)
Permeability
Definition:
ability of water to flow through
____ porosity = ____ permeability

8. Soil Composition continued…
As water infiltrates the soil, it can carry dissolved materials with it. Leaching: Removal of dissolved materials from the soil by water flowing through the soil.

9. Check for Understanding
Which type of soil (sand, silt, or clay) do you think has the highest permeability? Why? Why do you think loam is the best type of soil?

10. Physical: Ionic Charge
Clay particles have mostly negative charges on their outer surfaces.
Positively charged mineral ions are attracted to the soil particles and are held for plant use.
potassium K+ and magnesium Mg2+
Negatively charged mineral ions are repelled by the soil particles and are washed away from roots.
nitrate NO3-

11. Chemical Property: pH
Definition: pH is a measure of how acidic or basic something is.
Most soil pH is Plants are happiest at 
Why is pH important?
Certain minerals “stick” to soil better at certain pH levels.
Soil pH affects the leaching of nutrient minerals.
PESTICIDE TIE-IN: If soil is too acidic, applied pesticides, herbicides, and fungicides will not be absorbed (held in the soil) and they will end up in runoff

12. Dr. Greg Pillar, Queens College
Soil stores important nutrients
Phosphorus (P)
Nitrogen (N)
Potassium (K)
Calcium (Ca)
Magnesium (Mg)
Dr. Greg Pillar, Queens College

13. Soil Nutrients
Nutrients: essential chemical elements needed for the growth of healthy plants
Plants get nutrients from soil after the nutrients have dissolved in the soil solution (the water around soil particles)
Each nutrient has specific roles in producing healthy plants

14. NITROGEN
FUNCTIONS Used to make chlorophyll Responsible for rapid growth and health green leaves TOO LITTLE/TOO MUCH Not enough nitrogen?  Plant leaves turn yellow Too much nitrogen?  Long weak stems/no flowering

15. PHOSPHORUS FUNCTION Responsible for root development and growth
Helps plant produce flowers and fruit
Important in photosynthesis and respiration, energy transfer and storage
TOO MUCH/TOO LITTLE
Not enough phosphorus?
 Purplish or deep green leaves
 Poor root system
Too much phosphorus?
 No symptoms
 Plants NEVER have too much phosphorus— there’s not a lot out there—what does exist bonds to soil or leaches away quickly

16. POTASH/Potassium
FUNCTION Responsible for growth and regulation Helps regulate opening and closing of stomata TOO MUCH/TOO LITTLE Not enough potassium?  Brown scorching and curling of leaf tips  Purple spots on underside of leaves Too much potassium?  plant loses the ability to absorb other nutrients.