Healthy Plants

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• Healthy Plants
• Friable soils
• Proper nutrient balance
• Proper soil pH acid vs. alkaline
• Proper root and crown spacing
• Ample soil moisture
• Proper soil temperature
• Proper light levels
• Pure air
• Free of insects and diseases

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Crown
Flare or Root Collar
Root Zone
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Soil pH acidity or alkalinity of soils 1
acid 7 alkaline 14 To raise the pH, we
add limestone. (hydrated lime vs. dolomite
limestone) To lower pH, we add sulfur. (elemental
sulfur or iron sulfate)
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Soil Chemistry pH
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Soil Chemistry CEC
The Chemistry of Clay
Cationic Exchange Capacity (CEC)
Clay particles carry negative charges
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Soil-Plant Relationships
50 CEC Common CEC Range 0 CEC (heavy
clay) (sand)
Some Practical Applications
Soils with CEC 11-50 Range
Soils with CEC 1-10 Range
? High clay content ? More lime required to
correct a given pH ? Greater capacity to hold
nutrients in a given soil depth ? Physical
ramifications of a soil with a high clay
content ? High water-holding capacity
? High sand content ? Nitrogen and potassium
leaching more likely ? Less lime required to
correct a given pH ? Physical ramifications of a
soil with a high sand content ? Low water-holding
capacity
Source Potash and Phosphate Institute, 1992
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Nutrient Relationships
A crops yield is restricted by the lack of one
single element even though there may be
sufficient quantities of all other essential
elements. J. von Liebig
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Soil Chemistry
Common Soil Cations Anions

• Nitrate N NO3-
• Chloride Cl Cl-
• Sulphate S SO4--
• Phosphate P H2PO4-

• Potassium K K
• Hydrogen H H
• Sodium Na Na
• Calcium Ca Ca
• Magnesium Mg Mg
• Aluminum Al Al

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Roots absorb nutrients as water carries it to them
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How Much Water Should We Apply

• On a average summer day we loss about .25 to .3
  acre inches of water or 1.5 to 2 acre inches
  per week.
• One acre inch of water is equal to .6 of a
  gallon per square foot .
• Easy method to water is apply 5 gallons of
  water for the tree and 5 gallons for each inch
  of caliper.
• A two inch tree will receive 15 gallons of water
  a week, 5 gallons for the tree and 10 gallons for
  the caliper.

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Relative Water Usage of Different Types of Plants
grass
shrubs and groundcovers
trees
Estimated typical water usage of varying plant
types in relative amounts the amount of water
needed by plants varies with location and
climate. generally, lawns use more water than
trees, and trees use more water than both shrubs
and groundcovers.
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Rate at Which Water Moves in the Soil
Soil Types Infiltration rates
(inches/hour)
Sand gt0.8 Sandy silty
soils 0.4 to 0.8 Loams 0.2 to 0.4 Clay
soils 0.04 to 0.2
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What is Mulch?

• An organic or inorganic material applied to the
  soil surface, usually during the growing season,
  or over the plant for the dormant season.

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Why Mulch?

• Beautification
• To make surfaces more attractive
• To reduce soil splashing
• Enhance Usage
• To make surface areas more usable for paths,
  play, etc.
• Decrease Maintenance
• Surface Insulation
• To conserve moisture
• To moderate extremes in temperature

• Pest / Disease Management
• To prevent weeds
• To prevent disease
• To prevent insects
• Soil Amendment
• To improve aggregation
• To prevent soil compaction
• To increase water adsorption and retention
• To protect against erosion
• To increase soil fertility

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Mulching
When to Mulch

• In the Spring
• Allow soil to reach optimum temperature before
  mulching (gt 50 - 60?F.).
• Adjust application timing in relation to
  herbicide applications.
• During the Summer
• Monitor mulches for refreshing or replacement
  needs.
• In the Autumn
• On established plants, make a second application
  over the root zone at first indication of frost
  on the ground, to avoid freeze/frost heaving
  during the winter.
• For winter protection of crowns (e.g. roses),
  cover with mulch at first indication of frost on
  the ground, but prior to freezing.

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Using Mulches Correctly
How to Mulch

• Select mulch based on overall landscape needs and
  requirements.
• Be aware of effects on the soil
• Keep mulch depth at 1-3 inches
• Never apply more than 3 inches of new mulch
• Never allow more than 3 inches of mulch to
  accumulate when re-applying mulch.
• Keep mulch away from stems / trunks.
• As much as is practical, cover the entire root
  zone area to achieve maximum benefits in
  enhancing the soil structure.

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Mulch Problems

• Over-Mulching
• Stops free air exchange, suffocating roots.
• Blocks penetration of water / fertilizer
• Causes stem rot
• New roots may grow into mulch elevating the root
  system.
• Creates a rodent haven.

Volcano Mulch Method.
more than 2 feet high!
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Mulch Problems
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What Causes Girdling Roots
One and Only one reason Planting Depth.
Solutions ( nursery and landscape) 1.
Understanding root systems 2. Proper planting
depth 3. Dont mulch against the trunk of the
tree. 4. No backfill on existing trees.

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Pith of the Stem Girdling Root
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Adventitious Roots are a Sign of Problems

• When planted to deep a gap will form around the
  trunk.
• Adventitious roots grow rapidly in that opening
  and dont grow out into that soil .

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Cross Section of a Woody Stem
Phloem
Cambium
Vascular tissue that transmits tree food down
the tree
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Cross Section of a Woody Stem
Cambium
The meristem of the trunk of the tree, the only
cells in the trunk that divide. A layer of
vascular cells two cells thick
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Twig Anatomy
This years growth
Last years growth
Year before last years growth
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Tree Growth and Hormone Control
Hormones that Control Tree Function Auxins Cytokin
ins Gibberellins Ethylene Abscissic Acid
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Auxins Produced in the terminal buds Is
destroyed by sunlight Maintains dormancy of
adventitious buds Controls branch
structure Important in root development
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Excurrent
Decurrent
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Tree Growth and Hormone Control
Cytokinins Produced in the roots Important in
shoot initiation and growth
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Tree Growth and Hormone Control
Gibberellins Key in cell elongation Tree Growth
Regulators (TGRs) are antigibberellins
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Field Grown ( BB)

• Grown in native soils
• Roots are cut with shovels
• The ball is covered with burlap
• Up to 80 percent of the root system can be
  removed

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Container Plants

• Grown in artifical media
• Rapid root growth
• Depth of planting
• Soils different than the planting site
• Dries out fast
• Need to fertilizer often

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Hydrological Discontinuity
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Bare Root Plants

• Grown in the field or in soil less media
• The plants have the soil removed from the roots
• This is usually done during dormant periods
  unless there is a large maintenance budget
  available

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Know Your Supplier
1 ¾ hackberry, 18 balls all with 8 13 of
soil over first main order roots
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Planting
Tree planted 4 years ago burlap was not removed
from ball, and roots failed to penetrate burlap
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Hydrological Discontinuity
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How Does Water Move in the Soil
Percolation- water moving downward in the soil.
Excess water on the surface will cause runoff.
Capillary Action- water moving up in the soil
through the small pores against gravity. Seepage
- water moving sideways in the soil . Much of
this water can move into basements and open
sites. Runoff water that cant be absorbed
into the soil so it moves down hill. Issues are
erosion and loss of nutrients ( water
contamination)
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Pore and Air-Water Movement
Adhesion water
Cohesive water
available air in macropore
water
soil particle
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well
water table
surface water
unsaturated zone
Aquifer (saturated zone)
fractured bedrock
gravel
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Soils are a combination of weathered rock,
organic matter, and a vast complex of living
organisms.
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SOIL From the Ground, Up!
Soil Properties
They are not independent they interact to
affect soil characteristics
Biological
Chemical
Physical
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SOIL From the Ground, Up!
Soil Profile
it looks like a layer cake
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The Four Main Components of Soil are
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