Transcript Abiotic Disorders Presentation Part II

Abiotic Disorders:
Soil and Fertilizer Components
Janet Hartin
UCCE Environmental Horticulturist
San Bernardino, Los Angeles, and Riverside Counties
Major Components
• Mineral matter
• Organic matter
• Air
• Water
Physical Properties
of Soil
• Soil texture
• Soil structure
• Soil color
• Bulk density
USDA Textural Triangle
Soil Textures
Examples of Soil Structure
Granular
Blocky
(Subangular)
(Angular)
Prismatic
Columnar
Platy
Wedge
Compaction Can Destroy Soil
Where Does Compost Fit In?
What is composting?
Grass clippings
Food scraps
Leaves
Using the natural process of decay to
change organic wastes into a valuable
humus-like material called compost
Compost
Compost Promotes Soil Health
• Supplies organic matter to
soil
• Attracts earthworms
• Stimulates beneficial soil
microorganisms
• Increases soil and nutrient
water holding capacity in
sandy soils/drainage in
heavy soils
Compost Supplies Some Plant Nutrients
Compost is not a fertilizer,
but does contain plant
nutrients
• Nitrogen and phosphorus
are mostly in organic forms
– Released slowly to plants
– Not readily leached from the
topsoil
• Compost contains small
amounts of nutrients that
are essential for plant
growth
When is Compost Ready?
Compost is mature when
• It is dark brown
• It is crumbly, loose,
and humus-like
• It has an earthy smell
• It contains no readily
recognizable feedstock
• The pile has shrunk to
about 1/3 of its original volume
Simple Tests to Ensure Compost
Readiness
Bag test: Compost
left in a plastic bag
should remain
fresh-smelling
after two days!
Germination test:
Make sure that
seeds actually
germinate in it!
Using Finished Compost
• Soil amendment
– This is the main use of compost.
– Mix evenly into soil at least 6 inches deep for
annuals and 12 inches for shrubs. Add at least
30% by volume.
– Do not add compost to tree planting sites!
Avoid Root-Bound Trees!
Fertilizers and Plant Nutrition
Essential Plant Nutrients
• Macronutrients
– Required in relatively large amounts.
• Micronutrients
– Required in small amounts.
– Minor or trace elements.
Macronutrients
• Fall into one of three categories:
– Non-Mineral Elements
– Primary Nutrients
– Secondary Nutrients
Non-Mineral Elements
• (C) Carbon
• (H) Hydrogen
• (O) Oxygen
Primary Nutrients
• (N) Nitrogen
• (P) Phosphorus
• (K) Potassium
Secondary Nutrients
• (Ca) Calcium
• (Mg) Magnesium
• (S) Sulfur
Micronutrients
•
•
•
•
(Fe) Iron
(Cu) Copper
(Zn) Zinc
(B) Boron
• (Mo) Molybdenum
• (Mn) Manganese
• (Cl) Chlorine
Function & Deficiency Symptoms
of Nutrients
Nitrogen
• Function
– Promotes growth of leaves and stems.
– Gives dark green color and improves quality of
foliage.
– Necessary to develop cell proteins and
chlorophyll.
Nitrogen
• Deficiency Symptoms
– Sick, yellow-green color.
– Short stems, small leaves,
pale colored leaves and
flowers.
– Slow and dwarfed
plant growth.
Phosphorus
• Functions
– Stimulates early formation & growth of plants.
– Provides for fast & vigorous growth and speeds
maturity.
– Stimulates flowering & seed development.
– Necessary for the enzyme action of many plant
processes.
Phosphorus
• Deficiency Symptoms
– Decrease in growth.
– Slow maturity.
– Older leaves are
purplish color.
Potassium
• Functions
– Used to form carbohydrates & proteins.
– Formation and transfer of starches, sugars, & oils.
– Increases disease resistance, vigor, & hardiness.
Potassium
• Deficiency Symptoms
– Mottled, spotted,
streaked or curled
leaves.
– Scorches, burned,
dead leaf tips &
margins.
Potassium
• Deficiency Symptoms
– Mottled, spotted,
streaked or curled
leaves.
– Scorches, burned,
dead leaf tips &
margins.
Calcium
• Functions
– Improves plant vigor.
– Influences intake & synthesis of other plant
nutrients.
– Important part of cell walls.
Calcium
• Functions
– Improves plant vigor.
– Influences intake & synthesis of other plant
nutrients.
– Important part of cell walls.
Magnesium
• Functions
– Influence the intake of other essential nutrients.
– Helps make fats.
– Assists in translocation of phosphorus & fats.
Magnesium
• Deficiency Symptoms
– Interveinal chlorosis.
• (Yellowing of leaves
between green veins)
– Leaf tips curl or cup
upward.
– Slender, weak stems.
Sulfur
• Functions
– Promotes root growth and vigorous vegetative
growth.
– Essential to protein formation.
Sulfur
• Deficiency Symptoms
– Young leaves are light green with lighter
color veins.
– Yellow leaves and stunted growth.
Iron
• Functions
– Essential for chlorophyll production.
– Helps carry electrons to mix oxygen with other
elements.
Iron
• Deficiency Symptoms
– Mottled & interveinal
chlorosis in young
leaves.
– Stunted growth &
slender, short leaves.
Copper
• Functions
– Helps in the use of iron.
– Helps respiration.
Copper
• Deficiency
Symptoms
– Young leaves are
small and
permanently wilt.
– Multiple buds at
stem tips.
Zinc
• Functions
– Plant metabolism.
– Helps form growth hormones.
– Reproduction.
Zinc
• Deficiency Symptoms
– Retarded growth between nodes (rosetted)
– New leaves are thick & small.
– Spotted between veins, discolored veins.
Boron
• Functions
– Affects water absorption by roots.
– Translocation of sugars.
Boron
• Deficiency Symptoms
– Short, thick stems tips.
– Young leaves of
terminal buds are light
green at base.
– Leaves become twisted
& die.
Boron
• Deficiency Symptoms
– Short, thick stems tips.
– Young leaves of
terminal buds are light
green at base.
– Leaves become twisted
& die.
Manganese
• Functions
– Plant metabolism.
– Nitrogen transformation.
Manganese
• Deficiency Symptoms
– Interveinal chlorosis.
– Young leaves die.
Complete vs. Incomplete Fertilizers
• Complete Fertilizers
– Contain all 3 primary nutrients (nitrogen,
phosphorus, & potassium)
• Examples:
– 10-10-10
– 15-30-15
– 20-5-20
Complete vs. Incomplete Fertilizers
• Incomplete Fertilizers
– DO NOT have all 3 primary
nutrients.
• Examples:
– 20-0-0
– 0-20-0
– 12-0-44
Organic vs. Inorganic Fertilizers
• Organic Fertilizers
– Come from plant or animal matter & contain
carbon compounds.
• Examples:
– Urea
– Sludge
– Animal Tankage
Organic vs. Inorganic Fertilizers
• Advantages of Organic
Fertilizers
– Slow release of
nutrients.
– Not easily leached
from soil (less
potential to result in
water pollution).
– Add organic
components to soil.
Organic vs. Inorganic Fertilizers
• Disadvantages of Organic Fertilizers
– Expensive
– Low nutrient content
– Take longer to show effects
N-P-K Content of Some Organic Products
■ Alfalfa Meal
Average NPK analysis: 2-1-2
■ Blood Meal
Average NPK analysis: 12-0-0
■ Bone Meal
Average NPK analysis: Varies from about 1-11-0 to about 3-15-0, also contains
about 24 percent calcium.
■ Coffee Grounds
Average NPK analysis: 2-0.3-0.6
■ Compost
Average NPK analysis: 0.5-0.5-0.5 to 4-4-4; about (25 percent organic matter).
■ Cottonseed Meal
Average NPK analysis: 6-0.4-1.5
■ Eggshells (adds calcium mostly)
Average NPK analysis: About 1.2-0.4-0.1
■ Epsom Salts
Average analysis: 10 percent magnesium, 13 percent sulfur.
■ Feather Meal
Average analysis: Nitrogen 7 to 12 percent.
■ Fish Emulsion
Average NPK analysis: 5-2-2, also contains sulfur.
■ Mushroom Compost
Average NPK analysis: About 2-1-1
■ Soybean Meal
Average NPK analysis: 7-2-1
■ Worm Castings
Average NPK analysis: 0.5-0.5-0.3
Choosing a Fertilizer
General Rules
• Method used should be….
– Practical
– Effective
– Cost Efficient
• Method used affects nutrient availability for
plant use.
• Fertilizer must be dissolved and reach plant
roots.
Banding
• Placing a band of
fertilizer about 2
inches to the sides &
about 2 inches below
seed depth.
• Do NOT place below
seeds because
fertilizer will burn
roots.
Sidedressing
• Placing a band of fertilizer near the soil
surface and to the sides after seedlings
emerge from the soil.
Topdressing
• Mixing fertilizer uniformly into the top one to
two inches of growing media around the
plant.
Perforating
• Placing fertilizer in 12
– 18” holes drilled 18
– 24” around the
canopy drip line of
fruit trees.
• Cover the holes & the
fertilizer slowly
dissolves.
Broadcasting
• Spreading fertilizer to cover the entire
production area.
How much Fertilizer do Landscape
and Edible Plants Need?
Most vegetables:
-
0.5 to 2 lbs of nitrogen per 100 feet of row.
Ammonium phosphate (16-20-0) is a good choice if
compost hasn’t been worked into the soil
When seedlings are 3-4” reapply
Before planting fruit trees place one of the
following in the bottom of the planting hole
and cover with 1-2 inches of soil:
•1 lb treble super phosphate (0-45-0)
•2 lb single super phosphate (0-25-0)
•2 pounds fine phosphate rock*
•3 ½ pounds bone meal*
•7 to 8 pounds well composted/aged manure*
* Blend with backfill to avoid burning the roots.
Plant the tree. Then, spread an equal amount of one of the
above on the soil surface around the tree.
Nitrogen Application – Fruit Trees
Amount of nitrogen to Apply Per Tree Per Year
Season
Orange
Juice Can
Lbs. of
Lbs. of
Ammonium
Actual N
Sulfate
1st (after
planting)
½ can
(twice)
0.5
0.1
2nd
1 can
(twice)
1.0
0.2
3rd
3 cans
1.5
0.3
4th
5 cans
2.5
0.5
5th
7 cans
3.5
0.7
6th
8 to 10 cans 4.5
0.8 to 1.0
Landscape Tree Fertilization
- Not more than .5 lb N per inch trunk
circumference
- OK to wait until minor symptoms develop
Lawn Fertilization
Total: 4-5 lbs N/year
- 2-3 lbs N as ammonium sulfate
- 2-3 lbs N as a 3-1-2 ratio fertilizer
Lawns: 3-1-2 NPK Ratio
twice a Year
Why Have Garden Soil Tested?
Most Important Reasons:
- To determine pH (too high can tie up
micronutrients)
- To determine salt content (plant injury)
Other Reasons:
- To determine texture (sand, silt, clay) and water
holding capacity (although you can do this easily
yourself using a jar of water)
- To determine nutrient content (too much or too
little)
There is no Need to Test Levels of
Nitrogen Since it is so Mobile!
- Results will be invalid by the time you receive
the results
- Apply nitrogen based on MG Handbook
recommendations for various types of plants
How to Conduct a Soil Test
- Identify homogeneous areas of your yard
- Collect between 6-10 soil samples within each
area and mix them together thoroughly
- Sample depth should be between 6” and 1’
depending on type of plant and root zone
- Submit about 1 pint (2 cups) to a reputable
soil testing lab
Tips
- Avoid fertilizing or adding soil amendments just
prior to testing
- Make sure compost and other organic soil
amendments are broken down and stable
before their addition
- Consider water quality as well. It may need to
be tested
Tips (con’d)
Most nutrient-related problems can be
controlled simply by reducing pH and EC levels.
- High pH (above 7.5) can tie up nutrients such as
zinc, iron, and manganese.
- Add elemental sulfur or fertilizer with nitrogen
sulfate to reduce a high pH
- Add organic matter to your soil or garden in
raised beds amended with organic matter and/or peat
Refer to Table Below for Rates
Pounds of Sulfur Needed to Lower Soil pH
Material
pH Change
Pounds per 100 Square
Feet*
Sulfur
7.5 to 6.5
8.0 to 6.5
8.5 to 6.5
1.5
3.5
4.0
Iron sulfate
7.5 to 6.5
8.0 to 6.5
8.5 to 6.5
12.5
29.0
33.2
* Higher rates are required on fine-textured clayey soils and soils with a pH of 7.3
and above
Electrical Conductivity
- Measures how easily an electrical current can pass
through the soil
- High EC value indicates high salt levels
- Many plants are sensitive to salt contents as low as
3-4 dS/m. Most are sensitive to ECs above 8 dS/m
- Salts include cations and anions that are essential
plant nutrients (such as potassium and nitrate) as
well non-essential elements such as sodium
High Levels of
Sodium
A Few Very Salt-Sensitive Plants
-
Crape myrtle
Plum
Apple
Pear
Desert Willow
A Few Salt-Tolerant Plants
-
Honey locust
Honey Mesquite
Chilean mesquite
Salt Cedar
Salt grass
This Website Lists Salt Tolerances
of Several Plants
http://ucanr.org/sites/sjcoeh/files/98902.pdf
How Can you Reduce
Levels of Harmful Salts?
- Leach below the root system (apply water
slowly for several hours)
- If high EC is due to sodium, apply gypsum to
displace sodium with calcium (you still need to
leach the sodium out though!)
The Michigan State University Soil Test
Website Allows You to Type in Test
Results (pH, nutrient levels, CEC, etc. for
Specific Recommendations in
Landscapes and Gardens
Msusoiltest.com
Thank You!
Janet Hartin
[email protected]
(951)313-2023