1.

Training and Pruning Fruit Trees

2. Plant Nutrition and Fertilizers
Chuck Ingels
UC Cooperative Extension, Sacramento County

Advanced Master Gardener Training – Riverside

April 4, 2014
Fruit Tree Pruning
 Topics to be Covered

 Pruning Ornamental vs. Fruit Trees

 Post-Planting Pruning
 Dwarfing
 Fruiting Structures and Cut Types
 Summer Pruning
 Specific Training Methods
 Odd and Overgrown Trees
 Topics to be Covered

 Pruning Ornamental vs. Fruit Trees

 Post-Planting Pruning
 Dwarfing
 Fruiting Structures and Cut Types
 Summer Pruning
 Specific Training Methods
 Odd and Overgrown Trees
 Reasons for Training
Young Fruit Trees

 Create light penetration in

lower tree
 Support crop load
 Create access for ladder work,
fruit thinning, harvesting, etc.
 Ornamental vs. Fruit & Nut Trees
Differences

Landscape Trees Fruit & Nut Trees

 Taller trees  Shorter trees
 Central leader training  Many training methods
 First branch higher  First branch lower
 Mostly winter pruning  Winter, summer pruning
 Few if any heading cuts  Some heading cuts
 Branch spreaders rarely  Branch spreaders
used common
Ornamental vs. Fruit & Nut Trees
Similarities

 Branches carry heavy load

»Length vs. fruit load
 No narrow branch (crotch) angles
 Proper pruning cuts for wound closure
 May require support
»Cabling vs. rope or stake
 Topics to be Covered

 Pruning Ornamental vs. Fruit Trees

 Post-Planting Pruning
 Dwarfing
 Fruiting Structures and Cut Types
 Summer Pruning
 Specific Training Methods
 Odd and Overgrown Trees
 Post-Planting Care

• Head tree at 18-36 in. (bare root only)

• Cut back well-placed laterals to 3-8 in.,
remove all others
• Paint trunk white
Interior latex paint & water, 50:50
Entire trunk & 2 in. below soil
Prevents sunburn & borers
 Pruning a Bare-Root Tree

Branches thinner Branches thicker

than 3/16 than 3/16
New Shoots on Branches of
Newly Planted Tree
 Paint Trunks White
(Hot Climates, Afternoon Sun on Trunk)

To prevent this
 Topics to be Covered

 Pruning Ornamental vs. Fruit Trees

 Post-Planting Pruning
 Dwarfing
 Fruiting Structures and Cut Types
 Summer Pruning
 Specific Training Methods
 Odd and Overgrown Trees
 Semi-Dwarf vs. Genetic Dwarf

• Standard: 20-25+ ft.

• Semi-dwarf (dwarfing rootstock): 12-20 ft.
Variable dwarfing
• Genetic dwarf (std. rootstock): 8-12 ft.
Available in apricot, apple, olive, peach, nectarine,
pomegranate
Selection of varieties is limited
Not available in citrus, fig, pear, persimmon, plum/
pluot
Genetic Dwarf
Peach/Nect.
 INTERNODE LENGTH
Standard Peach Genetic Dwarf Peach
 Topics to be Covered

 Pruning Ornamental vs. Fruit Trees

 Post-Planting Pruning
 Dwarfing
 Fruiting Structures and Cut Types
 Summer Pruning
 Specific Training Methods
 Odd and Overgrown Trees
 More Fruit Tree Terms

• Scaffold branch: main structural limb

• Spur: short fruiting twig
• Shoot: current season elongated growth
• Water sprout: vigorous shoot from
branch
• Sucker: shoot from
rootstock or roots
 Apricot
Spurs

Cherry

A. pear Eur. pear

 Peach Fruiting
Branches

Flower
buds

Veg.
bud
 Heading Cut

• Removal of part of branch or shoot

• Used to promote branch development,
especially on young trees
• Stimulates growth just below cuts
• Can reduce sunlight penetration
 Thinning Cut

• Removal of entire branch

or shoot, or back to a
branch >1/3 the thickness
of cut branch
• Used to prevent crowding
and improve sunlight
penetration
• Defines main branches
 Topics to be Covered

 Pruning Ornamental vs. Fruit Trees

 Post-Planting Pruning
 Dwarfing
 Fruiting Structures and Cut Types
 Summer Pruning
 Specific Training Methods
 Odd and Overgrown Trees
 Summer Pruning
of Young Trees

• Purpose: promote scaffold branches

• Head unwanted shoots to 4-6 in.
• Pinch 2 ft. long shoots to promote side
branching if necessary
• Reduces training time, shortens time to
first fruit production
Summer Pruning for Training
(Open Center)

Before After
 Summer Pruning
of Mature Trees

• Purpose: To increase sunlight &

productivity of lower fruiting wood
• Remove unwanted vigorous, upright
shoots 1-2 times during season
• Bring down tree height
• Large branches may sunburn if
pruning is excessive
 Summer Pruning
(Plum)

Before

After
Prune Apricots and Cherries in August
to Avoid Branch Diseases
 Topics to be Covered

 Pruning Ornamental vs. Fruit Trees

 Post-Planting Pruning
 Dwarfing
 Fruiting Structures and Cut Types
 Summer Pruning
 Specific Training Methods
 Odd and Overgrown Trees
 Tree Shape Determines
Light Interception
Sunlight > ~ 1.5 X
Sunlight
1X

Shade

Shade
Sunlight Sunlight
Shade
 Improving Light Management

Sunlight >~2X
•More fruit color
Sunlight
•Strong buds
Sunlight
Sunlight •Strong flowers
•Larger fruit
Shade

Shade
Specific Fruit & Nut Tree
Training Methods

• Open center
• Central leader
• Modified central leader
• Perpendicular “V”
• Fruit bush
• Espalier
 Open Center

• Most common method

• Stone fruits and almonds; can
also use for apples, pears,
figs
• Select scaffolds during first 2 growing
seasons, touch up in dormant season
• Keep center open during summer from the
start
Pruning a One-Year-Old Peach
Pruning a Two-Year-Old Peach
Pruned Three-Year-Old Peach
Pruning a Mature Peach
Mature Peach/Nectarine
Tying Open Center Peach Tree
 Removing Old
Fruiting Wood

Cut back 2-year-

old branches to
healthy 1-year-
old branches
Prune Apricots in August
to Avoid Eutypa Dieback
Specific Fruit & Nut Tree
Training Methods

• Open center
• Central leader
• Modified central leader
• Perpendicular “V”
• Fruit bush
• Espalier
 Central Leader Apple
(Genetic Dwarf, planted 2000)

2004 2013
 Central Leader Training

• Used for apples, pears, Asian pears

• Maintain leader, remove at certain height
• Tie or stake lateral branches outward
• Create 3-4 whorls of branches
• Branches offset from those below
Central Leader Training
 Spread
Shoots When
Young
 Spread branches,
keep leader dominant
Persimmon (FOHC)
Central Leader
 Persimmon

 Bears laterally on current season’s growth

 Terminal & first few lateral buds on 1-
year-old branches are mixed
»Both male & female flowers
Persimmon Bearing Habit
 Persimmon Fruitful Shoots
at Tips of 1-Year-Old Branches
 Training Young
Persimmons
 Modified central leader
 3 - 5 main scaffolds
» 1 foot intervals
» 1st & 2nd year can pinch
shoots to promote
branching.
» Head branch ends you
want to keep growing
into scaffolds.
Unheaded Branches on Young Trees –
Lost Scaffold Branches, Sunburn
 Pruning Mature
Persimmons

 Dormant, annual
pruning
 Primarily small cuts
 Thin out to invigorate
and increase fruit size
Before
Mature Tree –
Mod. Central Leader

After
Specific Fruit & Nut Tree
Training Methods

• Open center
• Central leader
• Modified central leader
• Perpendicular “V”
• Fruit bush
• Espalier
Fruit Bushes Kept
at Desired Height
 Fruit Bushes
Pruning – Years 1 & 2

• At planting, head trees to 18-24 in.

• Mid-spring – cut back new growth by half
• Mid-summer – cut subsequent growth
back by half
• Thinning cuts for sunlight penetration
• May need to prune 1-2 more times
Cutting New Shoots in Half
Mid-Summer
 Fruit Bushes
Pruning Mature Trees

• Cut back new growth above selected

tree height 2-3 times during growing
season
• Thinning cuts for sunlight penetration
 Mature Fruit Bush
Maintaining Tree Height

Before After
 Cherry,
Pome Fruits
Ideal for Fruit
Bush
Apricot, Plum/Pluot Fruit Bushes
Vigorous Growth – Extra Work
 Apricot, Plum/Pluot Fruit Bushes
Vigorous Growth

Before After
 Fruit Bushes

• Advantages
Tree maintenance without ladder
Trees for small spaces
Sequential ripening
• Disadvantages
Less fruit
No shade
Timing of pruning critical
Key Summer Pruning Missed
 Excess Shading
Loss of lower branches
Specific Fruit & Nut Tree
Training Methods

• Open center
• Central leader
• Modified central leader
• Perpendicular “V”
• Fruit bush
• Espalier
 Espalier
Angle Shoots Upward Initially
Espalier Pruning
Growing Season

Source: Pruning and Training (Amer. Hort. Soc.)

 Dormant
Pruning

Before

After
 Espalier
Menorah Shape
Citrus Espalier (Mandarin)
 Espalier
Ensure Adequate Sunlight
 Espalier Peach

Peach
Cherry
 Espalier Peach
Row cover (Agribon)
Spring Pruning of Mature Peach Tree
Prune to 1 bud all but 2 shoots per branch

After harvest cut branch back to lower shoot

Peach Espalier
April 3, 2014
Peach Espalier
April 3, 2014
 Topics to be Covered

 Pruning Ornamental vs. Fruit Trees

 Post-Planting Pruning
 Dwarfing
 Fruiting Structures and Cut Types
 Summer Pruning
 Specific Training Methods
 Odd and Overgrown Trees
Peach
 Apple
Fruit bent branches
Pear
Persimmon
Before

Poor scaffold
branch
structure
 Persimmon
Before After

Stake
upright
 Methods of
Reducing Height of Large Trees

1. Cut to desired height in thirds over 3 years

 Thin upright shoots in summer to
provide light for lower fruiting wood
 Pruning
Overgrown Apple

What else can

be done?
Sunburn from First Topping
 Methods of
Reducing Height of Large Trees

1. Cut to desired height in thirds over 3 years

 Thin upright shoots in summer to
provide light for lower fruiting wood
2. Bring down height in one year
 Saw off limbs well below desired height
 Leave one “nurse” limb to feed roots
 Thin new shoots, train tree as desired
 Paint exposed limbs white
Pruning Overgrown
Apple – One Year

1999
1999
2012

2012
Fertilization
 Topics to be Covered

 Cation Exchange Capacity

 Plant Nutrients
 Fertilizers
 Fertilizing Specific Plant Types
 Organic Matter and Organic Fertilizers
 Synthetic vs. Organic Fertilizers
 Topics to be Covered

 Cation Exchange Capacity

 Plant Nutrients
 Fertilizers
 Fertilizing Specific Plant Types
 Organic Matter and Organic Fertilizers
 Synthetic vs. Organic Fertilizers
 Cation Exchange Capacity (CEC)

 A measure of soil fertility

 Clay and humus particles have neg. charge
 Varies by soil type and % organic matter

NH4+
Typical CECs Based on Soil Texture

Soil Texture Typical CEC Range

meq/100g
Sand 2–6
Sandy Loam 3–8
Loam 7 – 15
Silt Loam 10 – 18
Clay & Clay Loam 15 – 30
 Low vs. High CEC

CEC 1-10 CEC 11-50

 High sand content  High clay or OM content
 N & K leaching more  Greater capacity to hold
likely nutrients
 Less lime or sulfur  More lime or sulfur
needed to adjust pH needed to adjust pH
 Low water-holding  High water-holding
capacity capacity
 Topics to be Covered

 Cation Exchange Capacity

 Plant Nutrients
 Fertilizers
 Fertilizing Specific Plant Types
 Organic Matter and Organic Fertilizers
 Synthetic vs. Organic Fertilizers
 Essential Plant Nutrients

Major Major (Macro) Minor (Micro)

Nutrients from Nutrients Nutrients
Air & Water from Soil from Soil
Carbon Nitrogen Iron
Hydrogen Phosphorus Zinc
Oxygen Potassium Manganese
Calcium Copper
Magnesium Chlorine
Sulfur Boron
Molybdenum
 Mobility of Nutrients

Ionic Form Soil Mobility Plant Mobility

N NH4+ Immobile Immobile
N NO3- Mobile Mobile
P H2PHO4- Immobile Immobile
K K+ Immobile Mobile
Ca Ca++ Immobile Immobile
Mg Mg++ Immobile Mobile
Zn Zn++ Immobile Immobile
Mn Mn++ Immobile Immobile
 Roles of Nitrogen (N)

 Converts to amino acids in plant

» Building blocks for proteins
» Essential for cell division & plant growth
 Necessary for enzyme reactions
 Constituent of chlorophyll
(photosynthesis)
 Promotes vigorous vegetative growth
 “Simplified” Nitrogen Cycle
Biol. N Fix. Organics,manure,
Inorganic fertilizers
(legumes) compost

Inorganic nutrients
Example -Nitrate

Soil organic matter

Plant residues,
microbes, humus,
microbial by-
products, etc. Plants
leaching
harvest
 Movement of Nitrogen

 Taken up by plants primarily as nitrate (NO3-)

» Plant roots can absorb ammonium (NH4+) but it
is often bound to soil and cannot move as
easily to roots
 Leaching from root zone occurs easily
 Deficiency appears on older leaves first
because N is mobile
 Roles of Phosphorus (P)

 Plays role in photosynthesis, respiration,

energy storage & transfer, cell division &
enlargement
 Stimulates early growth & root formation
 Promotes flower and fruit development
 Promotes seedling root growth
 Contributes to disease resistance
 Does not easily leach
Roles of Potassium (K)

 Essential for photosynthesis

 Used for protein synthesis &
sugar translocation
 Important in membrane permeability
 Opening & closing of stomates
 Helps plant use water more
efficiently by promoting turgidity
 Increases disease resistance
 Nutrient Analysis
Soil Sampling

 Doesn’t always tell what plants take up

 Good for baseline info and detecting
deficiencies
 Sample in rooting zone from different areas
 Include at least 1 pint per sample in a quart
plastic zip-lock bag, take to lab
» See http://cagardenweb.ucdavis.edu
 Include: Total N, NO3-N, P, K, Ca, Mg, soil
texture, pH, OM, CEC, salts(?)
 Nutrient Analysis
Plant Tissue Sampling

 Tells what plant actually took up

 Standards only available for crop plants
 Best timing
» Annual crops – during active growth
» Tree crops – July
» Grapes – at bloom (petioles)
 Include 30+ leaves/sample  into small paper
bag, refrigerate, take to lab ASAP
 Include: N, P, K, Fe, Mn, Zn, salts(?)
 Topics to be Covered

 Cation Exchange Capacity

 Plant Nutrients
 Fertilizers
 Fertilizing Specific Plant Types
 Organic Matter and Organic Fertilizers
 Synthetic vs. Organic Fertilizers
 Should I Use Fertilizers?

 Garden soils rarely contain all required

nutrients
 Equally rare for garden soil to be
deficient in several nutrients
 Add only the nutrients that are deficient
 Making of Chemical
Nitrogen Fertilizers

 Natural gas = 98% methane (CH4)

 Chemical reactions  hydrogen gas (H2)
 Air = 78% N2
 Haber-Bosch Process:
 High pressure & heat  Makes ammonia (NH3)

Anhydrous
ammonia
Conversions of Ammonia to
Various N Fertilizers
 Examples of Chemical
Nitrogen Fertilizers

 Ammonium sulfate (21-0-0-24S)

 Ammonium nitrate (34-0-0)
 Urea (46-0-0)
 Highest %N; protein substitute in
animal feeds
 Slow-Release N Fertilizers

 Synthetic
 UF (urea formaldehyde), MU (methylene urea),
IBDU (isobutylidenediurea)
(uncoated; short & long-chain polymers)
 Polymer-coated (e.g., Osmocote)

 Longer lasting, not readily leached

 Label says “Slow Release Nitrogen”

 Water Insoluble Nitrogen (W.I.N.)

 Natural (e.g., compost, feather meal)

Polymer-Coated Fertilizer
 Potassium Fertilizers

 Mined, not manufactured

 KCl = Muriate of potash
 KSO4 = Sulfate of potash
 KCO3 = Potassium carbonate

 Mining and potash history to

be discussed later
 Fertilizer Analysis

N - P - K - S

21 - 0 - 0 - 24

Ammonium Sulfate
 Fertilizer Content

 By law, guaranteed content of fertilizer

must be stated on bag
 Expressed as % of each plant nutrient
applied
 N-P-K
 ‘Complete’ Fertilizers

Contain at least:
Nitrogen (N)
 % nitrogen (N)
Phosphorus (P)
 % phosphoric acid P2O5
Potassium (K)
 % potash K2O
Examples of Fertilizer Blend Ratios

Ratio
1-1-1 (e.g., 16-16-16): General purpose
2-1-1: Orn. & fruit trees, estab. lawns, leafy veggies
1-2-2: New lawns
1-2-1: Vegetables, seedlings, flowers, bulbs
0-1-1: Woody plants in fall
 Fertilizer Blends

 N-P-K numbers not always the same

 “Complete” fertilizer = Contains N, P, & K
 “Balanced” fertilizer = Equal amounts of N-P-K
 Examples: 16-16-16 (multi-purpose), 12-4-8
(fruit tree & vine), 5-10-10 (tomato & veg.), 4-8-
5 (camellia/azalea), 25-6-4 (lawns)
 Blends are not standardized!
 Chelating Agents (Chelates)

 Synthetic organic substances that maintain Fe,

Cu, Mn, and Zn in water-soluble form
 Makes them readily absorbed by plants
 Can be used to correct chlorosis (yellowing) of
leaves
 But best to lower soil pH
 Topics to be Covered

 Cation Exchange Capacity

 Plant Nutrients
 Fertilizers
 Fertilizing Specific Plant Types
 Organic Matter and Organic Fertilizers
 Synthetic vs. Organic Fertilizers
 Vegetable Fertilization
Veg. Gardening Basics, UC Pub. 8059

 Preplant: N-P or N-P-K

 Use 1/3 lb. N per 100 sq. ft.
 Dry steer manure: 100 lb. per 100 sq. ft.
 Chicken manure: 20 lb. per 100 sq. ft.
 Side dressing when plants 3-4” high
 0.4 lb. N per 100 sq. ft.
 Banded application
 Fruit & Nut Tree Fertilization
The Home Orchard, UC Pub. 3485

 Pounds per year of N to correct a deficiency:

 Large fruit trees: 1 lb.
 Small fruit trees: 0.5 lb.
 Large nut trees: 2 lbs.
 Small nut trees: 1 lb.
 Landscape Tree Fertilization
Planting Landscape Trees, UC Pub. 8046

“Adding fertilizer, soil amendments, or root

stimulants to the planting hole or backfill soil
is not recommended. Most nursery-grown
trees are well fertilized during production and
seldom respond to fertilizing at planting
except in the most infertile soils.”
 Tree Fertilization
Points to Remember

 Trees adapted to low soil N levels!

 Routine N-P-K fertilization unjustified unless
deficiency exists
 High N wasteful, polluting, and may increase
pest problems
 Trees in turf may not require fertilization
 Use compost, wood chip mulch
 Use slow release fertilizers
 FERTILIZING
“Adding fertilizer, soil amendments, or root
stimulants to the planting hole or backfill soil is
not recommended. Most nursery-grown trees are
well fertilized during production and seldom
respond to fertilizing at planting except in the
most infertile soils.”
 Nutrient Deficiencies are Rare
in Woody Ornamentals

 N – Sandy, overwatered, or sub soils

 P – Deficient in foothills
 Ca, Mg – Acidic or sandy soils
 Fe, Mn, Zn, B – High-pH or waterlogged soils
 Lawn Fertilization
Practical Lawn Fertilization, UC Pub. 8065

 Cool-season grass: 4 lbs. actual N/year

 Low N & water using species (buffalograss,
Zoysiagrass): 2 lbs. actual N/year
 Slightly less where grasscycling is used
 Up to 1 lb. N/application
 Organic and slow-release fertilizers:
Can use higher rate & fewer applications
 Topics to be Covered

 Cation Exchange Capacity

 Plant Nutrients
 Fertilizers
 Fertilizing Specific Plant Types
 Organic Matter and Organic Fertilizers
 Synthetic vs. Organic Fertilizers
 Soil Organic Matter

 Serves as energy source (food) for

microorganisms, which promote stable
aggregation of the soil particles
 Essential nutrients are obtained by plants
as organic matter decomposes
 Enhanced by OM additions but destroyed
by cultivation
 Humus

 What’s left over after organic

matter decomposes
 Cannot be seen by naked eye
 Very reactive (CEC)
 In equilibrium with organic matter
additions
 Animal-Based
Organic Fertilizers

 By-product of  Manures
animal slaughter  Bat guano
 Blood meal  Livestock manure
 Bone meal
 Feather meal
 Fish products
 Blood Meal
13-1-0.6 (80% protein)

 Bovine blood collected from processing

plants, agitated, dried, granulated
 Quick N release – ammonia can burn
plants
 Bone Meal
1-13-0 to 4-12-0, + 22% Ca

 Uses
 Blooming bulbs (P)
 May help prevent blossom-end rot (Ca)
 Also useful for root growth of transplants (P)
 Bone meal is alkaline, so apply to soils of pH < 7
 Need acidic soil to convert to plant-available P
 Feather Meal
Usually 12-0-0

 Made from feathers of slaughtered poultry by

hydrolyzing under high heat and pressure and
then grinding
 Slow release of plant-available N
 Fish Products

 Many forms, have some P, K, & micronutrients

 Fish emulsion, liquid fish (4-5% N)
 Derived from fermented remains of fish
 Has a fishy smell
 Hydrolyzed fish powder (11% N)
 Mixed with water and sprayed on plants
 Fish meal (powder) (10% N)
 Applied to soil
 Bat/Seabird Guano

 Poop from bats and seabirds – Islands in

Pacific & other oceans
 From caves – loss of bats & biodiversity
 Bat guano: 3-10% N, up to 12% P, 1% K
 Seabird guano: Up to 12% N & P, 0-2% K
 More expensive than land-animal manures
 Manures
Characteristics and Uses

 Poultry, dairy, feedlot, steer, rabbit, sheep/goat

 May contain salts that harm plant growth, and
weed seeds
 Poultry may have >3%N (ammonia smell)
 Aged feedlot manure may have <1% N
Nutrient Content of Manures & Composts
Org. Soil Amendments & Fertilizers, 1992

N P205 K20
Fresh broiler / rice hulls 3.9 2.6 2.7
Fresh layer 4.0 6.3 3.4
Aged layer 2.2 8.2 4.0
Fresh dairy corral 2.4 1.3 7.1
Aged steer corral 1.3 1.6 3.3
Broiler / rice hulls compost 1.9 4.3 2.5
Dairy compost 1.4 1.4 2.9
Dairy / steer compost 1.7 0.8 2.6
 Compost
Characteristics and Uses

 Contains most nutrients required by plants

 May contain weeds & plant pathogens
 N content usually about 1-1.5%, very slow
release
 Considered a soil amendment, not fertilizer
Available N from Manures, Compost
Decay Series

 UC research, 1970s
 Average plant-available N over 3 years
(years 1, 2, and 3):
 Chicken (90%, 10%, 5%)
 Dairy (75%, 15%, 10%)
 Feedlot (35%, 15%, 10%)
 Compost (~10% in year 1)
 Plant-Based
Organic Fertilizers

 Alfalfa meal
 Cottonseed meal
 Soybean based
 Kelp/seaweed
 Humic acid and
humate products
 Alfalfa Meal
(About 2-1-2)

 From alfalfa plants, pressed into pellets

 Also contains micronutrients
 Especially good for roses, also vegetables
 Fairly quick N release
 Cottonseed Meal
(About 6-2-1)

 Derived from the seed in cotton bolls

 Some people have concerns about heavy
pesticide use on cotton and remaining in
the seed oils, so they choose organic
 Very slow N release
 Kelp/Seaweed

 Derived from sea plants off Norway, N. Calif.

 Available as liquid, powder, or pellet
 Applied to the soil or as a foliar spray
 Little N-P-K, mainly used for micronutrients,
hormones, vitamins, and enzymes
 “Can help increase yields, reduce plant stress
from drought, and increase frost tolerance”
 Humic Acid and Humate Products

 Complex organic compounds

 Touted to enhance soil microbial life
 Enables plants to extract nutrients from soil
 Improves soil structure
 Enhances root development
 Helps plants withstand stresses
 May receive same benefits from adding
compost
 Mined
Organic Fertilizers

 Rock phosphate
 Potassium
 Muriate of potash
 Sulfate of potash
 Greensand
 Mining of Rock Phosphate

 Source : Natural deposits in N. America,

China, Morocco, & former Soviet Union
 N. America – Florida, Idaho/Mont./Utah/
Wyoming, N. Carolina, Tennessee
 Rock Phosphate

 Hard-rock phosphate
 20% P and 48% Ca – can raise pH
 Breaks down very slowly
 Soft-rock phosphate
 16% P and 19% Ca, many micronutrients
 Form that plants can use more easily
 Breaks down very slowly
 Mining of
Potassium Fertilizers

 World reserves deposited when water from ancient

inland oceans evaporated
 K salts crystallized into beds of potash ore
 Covered by thousands of feet of soil
 Most deposits chloride (KCl), some sulfate (K2SO4)
 From Canada (#1), Russia, Belarus, US (#7)
 New Mexico, Utah, Canada
 Potash

 K compounds and K-bearing materials (esp. KCl)

 Historically – KCO3 – Bleaching textiles, making
glass, making soap (lye)
 Made by leaching ashes and evaporating the
solution in large iron pots, leaving a white
residue called "pot ash“
 Term later used for K fertilizer
 KCl = Muriate of potash
 KSO4 = Sulfate of potash
 Potash Banding

 K attaches to soil particles

 K concentrated, so extra K
leaches down

 Broadcasting K (or P) on
ground has little effect –
nutrients are locked up in
top 1-2” of soil
 Must be banded or
incorporated
 Topics to be Covered

 Cation Exchange Capacity

 Plant Nutrients
 Fertilizers
 Fertilizing Specific Plant Types
 Organic Matter and Organic Fertilizers
 Synthetic vs. Organic Fertilizers
 Chemical (Inorganic) Fertilizers

 No C-H linkage, so not used as energy source by

soil microbes
 Most are quick-release
 Because of the lack of carbon, fertilizers “feed the
plant but not the soil.”
 Chemical vs. Organic Fertilization

 Plants take up nutrients from organic and

chemical sources (no preference)
 Organic fertilizers feed soil microbes and require
them for breakdown (“Feed the soil”)
 Microbes (and roots) release compounds like
organic acids, enzymes, and chelates  convert
nutrients from organic form into a plant-available
(soluble) form
Advantages of Chemical Fertilizers

 Nutrients available to plants immediately

 Produce exact ratio of nutrients desired
 Ratios and chemical sources easy to
understand
 Inexpensive
Disadvantages of Chemical Fertilizers

 Made from nonrenewable sources (fossil fuels)

 May not promote soil health
 No decaying matter for improving soil structure
 Most do not replace micronutrients
 Nutrients readily available  chance of overfert.
 Tend to leach faster than organic
 Long-term use can change soil pH, harm soil
microbes, increase pests
Advantages of Organic Fertilizers

 May also improve soil structure

 Most are slow-release; not easy to
overfertilize
 Renewable and biodegradable
 Can make your own from waste (compost,
worm castings) or obtain locally (manure)
Disadvantages of Organic Fertilizers

 May not release nutrients as they are needed

 Nutrient content of manure & compost often
unknown
 % nutrients usually lower than chemical
fertilizers
 Tend to be bulkier, requiring more fossil fuels;
more expensive
 How Does Fertilizer N Affect
Soil Organisms?

 Synthetic fertilizers are salts (not sodium

chloride). Salts affect microorganisms, but at
what quantities?
 Some fertilizers lower pH, hurts some
earthworm species, maybe some microorgs.
 How Much Does it Cost?

 2-lb. box with 12% nitrogen = ?

 2-lb. box with 12% nitrogen = 0.24 lbs. N

 $6 a box / 0.24 lb. N = ?

 $6 a box / 0.24 lb. N = $25.00/lb. N

Nutrient Costs of Selected Fertilizers
Local Nurseries, Jan. 2011
$/Lb. of N-P-K
Product Analysis (3-5 lb. bag/box)
CHEMICAL
Azalea/Camellia 4-8-5 $6.46
Rose 5-10-5 $5.49
Mult-Purpose 16-16-16 $2.29
Citrus 12-8-4 $4.58
“NATURAL” BRAND
Azalea/Camellia 4-5-4 $17.31
Rose 5-7-2 $16.07
Mult-Purpose 4-4-4 $18.75
Citrus 7-3-3 $11.25
 Nutrient Costs of Selected Fertilizers
Local Nursery vs. Peaceful Valley Farm Supply
Product Analysis $/Lb. N-P-K
LOCAL (3.0 to 3.5 lb.)
Alfalfa meal 4-8-5 $40.00
Blood meal 13-0-0 $16.81
Cottonseed meal 5-2-1 $21.43
Bat guano (1.5 lb.) 10-3-1 $38.10
PVFS (50 lb.)
Alfalfa meal 2.4-0-0 $18.33
Blood meal 13-0-0 $9.23
Cottonseed meal 6-2.5-1 $7.37
Bat guano (25 lb.) 10-6-2 $16.66
Nutri-Rich 4-3-3 $2.80
Organic Fertilization of FOHC Garden
Early Years
Fertilization of FOHC Garden
Currently

Pelleted composted
chicken manure
Cover Crop + Compost
 Questions?
https://cesacramento.ucanr.edu