Humic Acid Fertilizer

1.Chemical and Physical Properties

1.1 Chemical Structure and Composition

1.1.1 Humic Substance Classification

• Humic Acids (HA):
  • Molecular weight: 50,000-100,000+ Daltons
  • pH solubility: Soluble in alkaline conditions, precipitate in acidic pH
  • Color: Dark brown to black
  • Aromatic content: 30-45% of carbon structure
• Fulvic Acids (FA):
  • Molecular weight: 500-2,000 Daltons
  • pH solubility: Soluble in all pH conditions
  • Color: Light yellow to dark brown
  • Higher oxygen content and lower molecular weight than humic acids
• Humin:
  • Molecular weight: >100,000 Daltons
  • Insoluble in both acidic and alkaline conditions
  • Most stable fraction of humic substances
  • Forms soil organic matter matrix

1.1.2 Chemical Structure Characteristics

• Aromatic Components:
  • Benzene rings and phenolic structures
  • Quinone and hydroquinone groups
  • Lignin-derived aromatic compounds
  • Condensed aromatic systems
• Functional Groups:
  • Carboxyl Groups (-COOH): 300-870 cmol/kg
  • Phenolic Hydroxyl (-OH): 200-570 cmol/kg
  • Alcoholic Hydroxyl: Variable content
  • Amino Groups (-NH₂): Present in lower concentrations
  • Carbonyl Groups (C=O): Ketone and aldehyde functionalities

1.1.3 Physical Properties

• Appearance: Dark brown to black powder, granules, or liquid
• Solubility:
  • Water solubility varies with pH and source
  • Potassium humate: 80-95% water soluble
  • Sodium humate: 85-98% water soluble
  • Free humic acid: 5-15% water soluble
• pH:
  • Solid humic products: pH 4-6 (acidic)
  • Alkaline humate solutions: pH 8-11
  • Buffering capacity: Strong pH buffering effect
• Electrical Conductivity:
  • Variable depending on salt content
  • Potassium humate: 15-25 mS/cm at 1% solution
• Moisture Content: 8-15% for solid products

1.2 Source Materials and Quality Variations

1.2.1 Leonardite-Derived Humic Acids

• Source: Oxidized lignite coal deposits
• Characteristics:
  • High humic acid content (60-80%)
  • Low ash content (5-15%)
  • Consistent quality and composition
  • Dark brown to black color
  • Primary commercial source globally
• Geographic Sources:
  • North Dakota, USA (major source)
  • Germany, Czech Republic, Russia
  • China, India (emerging sources)

1.2.2 Compost-Derived Humic Substances

• Sources:
  • Municipal organic waste compost
  • Agricultural residue compost
  • Vermicompost (earthworm processed)
  • Biosolids compost
• Characteristics:
  • Lower humic acid content (15-35%)
  • Higher fulvic acid proportion
  • Variable composition depending on feedstock
  • Higher microbial activity
  • Fresh organic matter components

1.2.3 Peat and Sapropel Sources

• Peat-Derived Humic Acids:
  • Source: Sphagnum and sedge peat deposits
  • Characteristics: High fulvic acid content, acidic pH
  • Geographic sources: Canada, Russia, Northern Europe
• Sapropel-Derived:
  • Source: Freshwater lake bottom sediments
  • Characteristics: Balanced humic/fulvic ratio
  • Additional minerals and trace elements

1.3 Quality Standards and Specifications

1.3.1 International Standards

• Humic Acid Content:
  • Minimum 50-80% (dry weight basis)
  • Total humic substances: 60-85%
  • Fulvic acid content: 15-25%
• Physical Specifications:
  • Moisture content:
  • Ash content:
  • Particle size: 80-200 mesh for powders
  • Bulk density: 0.4-0.7 g/cm³
  • Chemical Purity:
    • Heavy metals:
    • pH: 4-6 for solid products
    • Electrical conductivity: Specified ranges
    • Organic matter: >85%

    1.3.2 Agricultural Grade Classifications

    • Technical Grade: 50-65% humic acid content
    • Standard Grade: 65-75% humic acid content
    • Premium Grade: 75-85% humic acid content
    • Super Concentrate: >85% humic acid content
    • Liquid Formulations: 10-15% humic acid in solution