Transcript Soil Fertility Andrew Laca

Soil Fertility
Original by Andrew Laca
Modified by Georgia Agricultural
Education Curriculum Office
July, 2002
Terms and definitions
• Essential Nutrient- Element necessary for
plant growth and reproduction, for example:
nitrogen, phosphorus, and potassium.
• Deficiency- Plant condition where an
essential nutrient is not sufficiently
available.
• Symptom- A visual sign or condition that
results from a deficiency: symptoms aids in
diagnosing a deficiency.
More Terms and Definitions
• Fertilizer- Natural, manufactured, or
processed material or mixture of materials
that contains one or more of the essential
nutrients; available in:
– dry form
– liquid form
– gaseous form
Fertilizer Terms
• Analysis- Percentage water soluble content
of nitrogen (N), phosphorus (P) expressed
as P2O5, and potassium (K) expressed as
K2O in the fertilizer.
• Brand- Trademark of the company which
produced the fertilizer.
• Complete Fertilizer- Fertilizer which
supplies all three primary nutrients, (N,P,K)
Chemical Elements Essential
To Plant Growth
• Non-mineral- air and
water
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–
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Carbon (C)
Hydrogen (H)
Oxygen (O)
Nitrogen (N)
• Mineral- from the soil
– Primary
• Nitrogen (N)
• Phosphorus (P)
• Potassium (K)
– Secondary
• Calcium (Ca)
• Magnesium (Mg)
• Sulfur (S)
– Micronutrients
• Iron (Fe), Boron (B),
Manganese (Mn), Copper
(Cu), Zinc (Zn), Molybdenum
(Mo), Clorine (Cl)
10 Essential Elements
• Essential Elements
–
–
–
–
–
–
–
–
–
–
Carbon (C)
Hydrogen (H)
Oxygen (O)
Phosphorus (P)
Potash (K)
Nitrogen (N)
Sulfur (S)
Calcium (Ca)
Iron (Fe)
Magnesium (Mg)
C. HOPKINS CAFÉ Mighty Good
Functions of Nutrients for plant
growth
• Carbon, Hydrogen, and oxygen are needed
in the plant processes of photosynthesis of
photosynthesis and respiration.
• Approximately 95% of weight of plants
comes from products of photosynthesis
Primary Nutrient Functions
• Nitrogen (N)
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–
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Gives green color to plant
Induces vigorous , rapid growth in plants
Increases protein and yield
Aids and promotes seed and fruit development
Nitrogen constitutes 80% of the atmosphere,
yet it is one of the most critical elements for
plant growth.
– Plants cannot utilize N as a gas, it must be
combined with other elements.
More Primary Nutrient Functions
• Phosphorus (P)
– Important to germinating seedlings
– Contributes to early maturing crops
– Necessary for seed and fruit formation
– Stimulates root growth
Primary Nutrient Functions Cont.
• Potassium (K)
– Necessary for production and translocation of
carbohydrates
– Produces plumper seeds
– Controls Water intake and respiration
– Stiffens straw and stalks
Secondary Nutrient Functions
• Sulfur (S)
– Necessary for nodule formation on legumes
– Associated with plant enzyme systems
– Stimulates seed production
– Affects protein and crop quality
Secondary Nutrient Functions
• Calcium (Ca)
– Speeds decay of organic matter
– Stimulates formation of nitrates
– Promotes root and leaf growth
– Necessary for nodulation of legumes
Secondary Nutrient Functions
• Magnesium (Mg)
– Necessary for chlorophyll or green plant color
– Increases adsorption of phosphorus
– Aids in the formations of fats and oils
– Important in plant enzyme system
Symptoms of nutrient deficiencies
• Review
– Deficiency- Plant condition where an essential
nutrient is not sufficiently available.
– Symptom- A visual sign or condition that
results from a deficiency: symptoms aids in
diagnosing a deficiency.
Primary nutrient deficiency symptoms
• Nitrogen (N)
– Stunted and Spindly
– Yellow, yellowish green or light green in color
in foliage (chlorosis)
– Older leaves affected first, starting at the tip
and moves along the middle of the leaf.
Primary nutrient deficiency
symptoms
• Phosphorus (P)
– Stunted Growth
– Very dark green color
– Purple leaves or portions of leaves in advanced
stages
– Older leaves affected first
Phosphorus Deficiency
Primary nutrient deficiency
symptoms
• Potassium (K)
– Shorter plants
– Bronzing or browning of leaf color
– Lodging (bending of the stem) occurs
– Leaves show yellow to brown coloring along
leaf margins followed by complete browning.
Potassium Deficiency
Secondary nutrient deficiency
symptoms
• Sulfur (S)
– Young plants have stunted appearance
– Leaves have a light-green to yellow coloring
– Stems are thin and spindly
– Sulfur deficiency symptoms are similar in
appearance to nitrogen deficiency symptoms.
Secondary nutrient deficiency
symptoms
• Magnesium (Mg)
– Leaf parts between veins show a whitish color
– Leaf tissue becomes yellow, veins remain green
(interveinal chlorosis)
– Leaves curl upward along the margins
Deficiency Continued
• Other conditions besides deficiencies
may cause abnormal plant growth.
– Cold, wet weather, lack of sunlight,
disease, insect damage, and improperly
applied chemicals are examples.
Factors that Influence Fertilizer
Use
• Chemical and physical condition of the soil
• Crop to be grown
• Climatic Conditions
• Time