Soil Fertility
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; availible 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– 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)
– 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