SOIL PROPERTIES - PowerPoint Presentation

Slide1

SOIL PROPERTIESA crash course in soilsWednesday, November 5

Take out paper for Cornell notes! Slide2

And remember…Red text on top = HeaderBlack text = notes for you to copy OR paraphrase/ summarize

Grey text = Liu’s talking points, no need to copy it downUnderlined words = Important vocabSlide3

What are some soil properties?TexturePermeabilityPorosity

pHNutrient Levels—Nitrogen/Phosphorus/PotashSlide4

SOIL TEXTURESoil 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.Slide5

Physical Property: TextureTexture

determines the type of soil, and the soil’s properties.

Loam

: ideal for agricultural soilSlide6

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 LOAMSlide7

Physical: Porosity & Permeability

Definition:amount of pore spaces in soil (aeration)

Porosity

Permeability

Definition:

ability of water to

flow through

____ porosity = ____ permeabilitySlide8

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.Slide9

Check for UnderstandingWhich 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?Slide10

Physical: Ionic ChargeClay 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 Mg

2+

Negatively

charged mineral ions are

repelled

by the soil particles and are washed away from roots.

nitrate NO

3

-Slide11

Chemical Property: pHDefinition: pH is a measure of how acidic or basic something is.Most soil pH is 4-8. Plants are happiest at 6-7.

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 Slide12

Soil stores important nutrients

http://www.lesco.com/

Phosphorus (P)

Nitrogen (N)

Potassium (K)

Calcium (Ca)

Magnesium (Mg)

Dr. Greg Pillar, Queens CollegeSlide13

Soil NutrientsNutrients

: essential chemical elements needed for the growth of healthy plantsPlants 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 plantsSlide14

NITROGENFUNCTIONSUsed to make chlorophyll

Responsible for rapid growth and health green leavesTOO LITTLE/TOO MUCH

Not enough nitrogen?



Plant leaves turn yellow

Too much nitrogen?



Long weak stems/no floweringSlide15

PHOSPHORUS

FUNCTIONResponsible for root development and growthHelps 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 quicklySlide16

POTASH/Potassium

FUNCTIONResponsible for growth and regulationHelps 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.