B3. Mineral Nutrition

• Mineral Nutrition in plants

  Plants are: Capable of making all necessary organic compounds from inorganic compounds and elements in the environment (autotrophic). Supplied with all the carbon, hydrogen, and oxygen they could ever need (CO2, H2O). Required to obtain all other elements fro the soil so in a sense plants act as soil miners.
• Nutrient


  any substance that can be metabolized by an organism to give energy and build tissue

  • growth and development
• Categories

  • Based on Function

  1. Essential
  2. Beneficial

  • Based on amount required by crop

  1. Macroelements
  2. Microelements

  • Based on capability to move from one part of the plant to another

  1. Mobile
  2. Immobile
• Criteria of Essentiality

  1. If the nutrient is absent, then the plant is unable to complete its life cycle
  2. The function of the nutrient must not be replaceable by another element
  3. The nutrient must act directly in the metabolism of the plant
• Functions of the Essential Elements

  1. Structural
  2. Catalytic
  3. Osmotic
• Structural

  • important components of biomolecules (e.g. Nitrogen, Phosphorus, Calcium, Magnesium, Sulfur
• Catalytic

  • as co-factor of enzymes (e.g. most micronutrients)
• Osmotic

  • regulation of cellular hydration (e.g. Potassium)
• Macronutrients

  • Needed in large amount (1-10 milligram per gram of dry matter)
  • Nitrogen(N), Phosphorus (P), Potassium(K), Calcium(Ca), Sulfur(S), Magnesium(Mg), C, H, O
• Micronutrients

  • Needed in small amount (0.1 mg per gram of dry matter)
  • Iron(Fe), Boron(B), Copper(Cu), Zinc(Zn), Manganese(Mn), Molybdenum(Mo), Chloride(Cl-)
• Essential Nutrients Components

  Nutrients:

  
• Beneficial Elements

  • Elements which promote plant growth in many plant species but are not necessary for completion of the plant life cycle
  • Silicon(Si), Sodium(Na), Cobalt(Co), Selenium (Se)
• Decline in Soil Fertility

  ~ Soil Erosion

  • physical lost and displacement of the fertile topsoil

  1. Geographic Erosion
  2. Wind erosion
  3. Water-borned erosion
  4. Accelerated erosion due to human activity

  ~ Crop Removal

  ~ Conversion of nutrients to unavailable forms

  • Formation of insoluble forms
  • Microbial mediated transformations
  • Volitilization (especially nitrogen)
  • Leaching
• Recommended pH level for plant roots and soil microbes

  pH of 5.5 to 6.5
• Nutrient Deficiencies

  • Mineral nutrient deficiencies occur when the concentration of a nutrient decreases below its typical range
  • Deficiencies of specific nutrients lead to specific visual, often characteristic, symptoms reflective of the role of that nutrient in plant metabolism
• Nutrient Deficiency Symptoms

  • Chlorosis: (uniform or interval) or yellowing of the leaves due to chlorophyll degradation (Iron deficiency)
  • Necrosis: (tip, marginal, or interveinal) or death of leaf tissue (Mg, Ca, Cu, K deficiency)
  • Lack of New Growth: which may result in death of terminal or axillary buds and leaves, dieback, or resetting (Ca Deficiency)
  • Accumulation of Anthocyanin: resulting in reddish coloration of leaf tissues (N Deficiency)
  • Stunted leaf growth: with green, off-green, or yellow color (Nitrogen Deficiency)
• Mobile Nutrients

  • If the deficiency is seen in old leaves
  • Nitrogen, Potassium, Magnesium, Phosphorus, Chlorine, Sodium, Zinc, Molybdenum
• Immobile

  • If the deficiency is seen in young leaves
  • Calcium, Sulfur, Iron, Boron, Copper
• How to address Nutrient Deficiency

  1. Establish an attainable yield level - the crop's total needs
  2. Calculate the Nutrient requirement of the crop
  3. Effectively use existing nutrients

  I. Organic Fertilizers

  • manure
  • plant biomass
  • vermicompost
  • fermented plant juice

  II. Nutrients from irrigation water

  III. Indigenous soil nutrients

  4. For deficiencies, top up or add inorganic fertilizers