Soils

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Soils

• Outer layer of earths crust which has the
  capability of sustaining plant growth.

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Soils

• Also has the ability to
• anchor plants
• hold water
• provide nutrients
• house microorganisms
• serve as a water filter
• absorb and produce gases
• provide geologic history

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Soil Formation

• Parent Material-Bedrock
• Weathering process
• Reduction in particle sizes
• Primary Minerals - inert particles such as sand
  and silt.
• Secondary Minerals - highly charged particles
  such as clay (lt .002 mm)

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Soil Profile
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Basic Soil Composition

• Mineral Matter-from parent material
• Primary minerals
• Secondary minerals
• Organic Matter
• Decaying plant and animal residue
• Water
• Air

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Soil Properties

• Physical
• Chemical

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Physical Properties Soil Texture

• Relative amounts of sand silt and clay in a soil.
• Relative sizes of particles
• Sand 2-.05 mm
• Silt .05-.002 mm
• Clay lt .002 mm
• Obtained by particle size distribution

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Crystalline Structure
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Soil Texture Triangle
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Soil Structure

• Manner in which clay particles are arranged to
  form clods or peds.
• Blocky
• Columnar
• Prismatic
• Platy
• Angular

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Granular
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Blocky
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Columnar
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Platy
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Soils

• Chemical Properties

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Soil pH
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Soil pH

• Acidity or Alkalinity
• Acid or Base
• pH Values-pH scale 0-14, 7neutral
• High pH Low pH
• Effect of pH on plant growth
• Effect of pH on nutrient availability

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pH
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pH and Nutrient Availability
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Cation Exchange

• Dynamic process in which cations are continually
  replaced/exchanged on clay particles.
• Depends on water, root activity, type of clay,
  fertilizer added.
• H replaces Ca replaces Mg replaces K
  replaces NH4 replaces Na

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Cation Exchange

• Process can begin with active root growth
• Actively respiring roots give off CO2
• This CO2 reacts with water to from carbonic acid
• The acid gives off H which begins the process

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Cation Exchange

• H gt Ca gt Mggt K gt NH4 gt Na

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Vermiculite

• (Mg,Ca)0.7(Mg,Fe3,Al)6(Al,Si)8O20(OH)4 8H2O

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Soil Moisture

• Levels
• Too much
• Field Capacity
• Desirable levels
• Permanent wilting point
• Too little

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Soil Moisture Levels

• Crystalline Water - (Mg,Ca)0.7(Mg,Fe3,Al)6(Al,Si
  )8O20(OH)4 8H2O
• Hygroscopic Water
• Capillary Water
• Gravitaional Water

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Soil Moisture
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Soil Moisture
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Moisture Levels

• Field Capacity-maximum amount of water a soil can
  hold after surface runoff and gravitational
  drainage.
• Permanent Wilting Point (pwp)- point at which
  incipient plasmolysis has taken place and plant
  will not recover.

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Soil Amending

• Increase Drainage?
• Retain Moisture?

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Effect of Pore Size on H2O Holding Capacity

• Larger Pore Size?
• Smaller Pore Size?

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Soil Fertility

• Dependent on
• pH
• CEC
• Soil Moisture
• Nutrient Availability

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Plant Nutrients

• 16 Essential Elements
• Macronutrients
• Primary- C, H, O, N, P, K
• Secondary-Ca, Mg, S,
• Micronutrients
• Fe, Mn, B, Cu, Zn, Mo, Cl

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Plant Nutrients

• From Atmosphere and Water
• C Carbon
• HHydrogen
• Oxygen

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Plant Nutrients

• From the addition of fertilizers
• N Nitrogen
• P Phosphorus
• K Potassium
• Ca Calcium
• Mg Magnesium
• S Sulfur

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Role of Nitrogen

• Proteins
• Amino acids
• Nucleic acids
• Chlorophyll

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Nitrogen in Soil

• Obtained by N cycle
• Amendments such as compost
• Organic matter
• Added as NH4 or NO3-

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N Cycle
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Role of Phosphorus

• Vital component of energy molecules such as ATP,
  NADP etc.
• Added to soils as phosphate fertilizers. Less
  available in acid soils.

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Role of Potassium

• Assists in sugar and nutrient transport by
  creating concentration gradients.
• Applied to soils as potash or K2O

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Roles of other nutients

• Calcium cementing agent for cells in area
  called the middle lamella.(Dolomite/Lime)
• Magnesium central atom of chlorophyll molecule
  (Dolomite)
• Sulfur important component of vital amino acids
  such as cystine and methionine (Sulfur)

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Minor Elements

• Iron Chlorophyll synthesis, added as chelated
  iron, unavailable in alkaline soils.

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Minor Elements

• Serve as catalysts in various biochemical
  reactions.
• Boron
• Manganese
• Copper
• Zinc
• Molybdenum
• Chlorine

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16 Essential Plant Nutrients

• CHOPKNS CaFe Mg B Mn CuZn Mo Cl.

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The part of the seed that provides the initial
food source in the process of germination is
called the

• a. hypocotyl
• b. endosperm
• c. egg
• d. embryo
• e. none of the above

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Good "viability" of a seed lot refers to

• a. clean seed
• b. freedom of diseases and insects
• c. good germination percentage
• d. true to name

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Plant disease causing organisms such as those
belonging to the Pythium and Rhizoctonia species
can kill germinating seedlings. This condition
is known as

• a. sloughing off
• b. damping off
• c. killing off
• d. all of the above

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Propagation of plants without the use of seed can
be referred to as

• a. asexual propagation
• b. seed propagation
• c. sexual propagation
• d. a and b are correct

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Cuttings taken from partially matured new growth
of woody plants such as azaleas and camellias are
referred to as

• a. hardwood
• b. softwood
• c. semi-hardwood
• d. semi-greenwood

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Specialized cuttage practices, which may greatly
enhance good root production and formation
include

• a. bottom heat
• b. intermittent mist
• c. sanitary measures
• d. all of the above

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Synthetic auxins in rooting hormone products such
as "Rootone" and Hormodin are in the form of

• a. IBA
• b. ABA
• c. IBI
• d. NCAA

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Which of the following soil mediums would provide
the best conditions for rooting of cuttings?

• a. 75 peat moss to 25 perlite
• b. 20 peat moss to 80 vermiculite
• c. 20 peat moss to 80 sphagnum moss
• d. 20 peat moss to 80 perlite

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The reason(s) for grafting is(are)

• a. to produce a dwarfing effect
• b. to produce a plant that will not root by
  cuttings
• c. to use disease resistant rootstocks
• d. all of the above

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Highly weathered mineral particles such as clays
are classified as

• a. primary minerals
• b. secondary minerals
• c. inert minerals
• d. amorphous minerals

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The moisture holding capacity of a soil increases
as

• a. organic matter levels increase
• b. size of mineral particles decrease
• c. size of mineral particles increase
• d. a and b are correct
• e. a and c are correct

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The formation of soil aggregates or clods is
associated with

• a. soil structure
• b. soil texture
• c. soil fixture
• d. soil mixture

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The maximum amount of water that a soil can hold
after surface runoff and gravitational drainage
is called

• a. hygroscopic water
• b. capillary water
• c. field capacity
• d. gravitational water
• e. none of the above

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Fertilizers

• Compounds providing supplemental nutrients.
• Organic
• Natural
• Synthetic
• Inorganic/Chemical

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Terminology

• Fertilizer analysis or grade
• Three part number on bag/package
• Fertilizer ratio
• Lowest common multiple of analysis or grade
• Complete fertilizer
• Contains all three of the major elements N, P and
  K

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Terminology

• Balanced Fertilizer
• contains all three nutrients in equal amounts.
  (8-8-8)
• Single or Double nutrient Fertilizer
• Contains only one or two of the main nutrients
• 46-0-0 or 13-0-44.
• High Analysis-total nutrients over 30
• Low analysis-total less than 30

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Organic

• Derived from plant and animal by-products.
• Examples
• Manure
• Blood meal
• Bone meal
• Sewage sludge

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Organic-Characteritics

• Low analysis
• Low burn potential
• More material required per given rate
• May contain heavy metals such as cadmium and
  manganese

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Synthetic Organic

• High analysis
• Slow release
• Manufactured in combination with an organic
  carrier
• Low burn potential
• Use more material at higher rate to last longer
• Expensive

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Examples

• Urea
• Ureaform - Ureaformaldehyde
• IBDU Isobutylidene di-urea
• SCU sulfur coated urea

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Inorganic- Characteritics

• High analysis
• High burn potential
• Use less material per given rate

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Examples

• Ammonium sulfate
• Ammonium nitrate
• Calcium nitrate
• Ammonium phosphate
• Gypsum
• Epsom salts

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Formulations

• Liquids
• Soluble powder
• Granules
• Tablets

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Fertilizer contents

• 100 bag of 10-20-30 contains
• 10 of N
• 20 of phosphate (P2O5)
• 30 of potash (K2O)

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Methods of application

• Topdressing
• Pre-plant incorporation
• Side dressing
• Needle/Drill - subsurface
• Foliar
• Injection