W6 - Topic 11 - Soil Nutrition Flashcards
What do plants obtain from soil for proper growth and development?
Essential nutrients
Nutrients must be dissolved in water before plants can absorb them.
What are the two types of ions that nutrients exist as in solution?
Cations and Anions
Cations are positively charged ions, while anions are negatively charged ions.
List four examples of cations.
- K⁺
- Ca²⁺
- Mg²⁺
- Na⁺
List four examples of anions.
- NO₃⁻
- PO₄³⁻
- SO₄²⁻
- Cl⁻
What are macronutrients?
Nutrients needed in larger quantities
Examples include Carbon, Hydrogen, Oxygen, Nitrogen, Phosphorus, Potassium, Calcium, Magnesium, and Sulfur.
What are micronutrients?
Nutrients needed in smaller quantities
Examples include Boron, Chlorine, Cobalt, Copper, Iron, Manganese, Molybdenum, and Zinc.
What is cation exchange?
The process where clay and organic colloids attract and hold positively charged cations in the soil
They exchange nutrients with H⁺ from plant roots.
How does pH influence nutrient availability?
Significantly influences it; most nutrients are optimally available at pH 6.5
High pH reduces micronutrient availability, while low pH reduces macronutrient availability.
What is Liebig’s Law of the Minimum?
Plant growth is limited by the scarcest essential nutrient
Increasing plentiful nutrients will not improve growth.
What are mobile nutrients?
Nutrients that can be relocated within the plant
Deficiency symptoms appear in older leaves first.
List four examples of mobile nutrients.
- Nitrogen (N)
- Phosphorus (P)
- Potassium (K)
- Magnesium (Mg)
What are immobile nutrients?
Nutrients that cannot be easily relocated within the plant
Deficiency symptoms appear in new growth first.
List four examples of immobile nutrients.
- Calcium (Ca)
- Sulfur (S)
- Iron (Fe)
- Boron (B)
What is the role of nitrogen in plant nutrition?
Essential for green foliage growth and protein synthesis
What are the deficiency symptoms of nitrogen?
- Yellowing of older leaves (chlorosis)
- Stunted growth
- General pale appearance
What solutions can be applied to correct nitrogen deficiency?
- Add organic matter
- Plant green manure crops
- Practice crop rotation with nitrogen-fixing legumes
- Apply nitrogen fertilizers
What is the role of phosphorus in plant nutrition?
Critical for root development and cell wall formation
What are the deficiency symptoms of phosphorus?
- Purple coloration on older leaves
- Stunted growth
- Oldest leaves turn brown and die
- Poor flowering and fruiting
What solutions can be applied to correct phosphorus deficiency?
- Add organic matter
- Apply rock phosphate
- Use phosphate fertilizers
What is the role of potassium in plant nutrition?
Important for bud, flower, and fruit development
What are the deficiency symptoms of potassium?
- Lack of growth and flowers
- Older leaves become mottled
- Necrosis of leaf tips and margins
What is the role of magnesium in plant nutrition?
Central component of chlorophyll, essential for photosynthesis
What are the deficiency symptoms of magnesium?
- Edges of older leaves turn yellow
- May develop red spots
What is the role of calcium in plant nutrition?
Provides structural strength to cell walls and stems; supports leaf and root growth
What are the deficiency symptoms of calcium?
- New growth curls
- Brown spots and tip burn
- Rot of buds, flowers, and fruit
- Young leaves are small and slow-growing
What is the role of sulfur in plant nutrition?
Essential for amino acid and protein formation; promotes beneficial bacteria
What are the deficiency symptoms of sulfur?
- Light green leaves with dark interveinal areas
- Young leaves affected
- Weak stems
What is the role of iron in plant nutrition?
Critical for chlorophyll formation
What are the deficiency symptoms of iron?
- Chlorosis at the top of the plant
- Leaves yellow with green veins
What is the role of boron in plant nutrition?
Important for plant cell development and reproductive processes
What are the deficiency symptoms of boron?
- Corky spots on fruit
- Rust-colored cracks in stems
- Plants fail to flower
- Growing tips die
What are common nutrient toxicities?
- Nitrogen
- Phosphorus
- Aluminum
Often caused by over-fertilization.
What are the symptoms of nitrogen toxicity?
- Dense, dark green foliage
- Excessive foliage growth at the expense of roots, fruits, and flowers
- Leaves may dry out and fall off
What can mimic nutrient deficiencies?
Environmental and genetic factors
Factors include water stress, weather damage, normal plant features, and pest/disease issues.
What is the importance of soil testing in nutrient management?
Helps identify deficiencies before visual symptoms appear
What is the benefit of balanced fertilization?
More effective than reactive treatments based on soil tests
