Horticulture Lecture 5: Post-planting Practices

Fertilization

• Fertilization is an essential agricultural practice to supply growing plants with nutrients, enhancing their growth and productivity.
• A fertilizer is a natural or synthetic substance containing one or more recognized plant nutrients, applied to the soil or the plant to adjust the growing plant's nutritional status.

Types of Fertilizers

• Organic fertilizer
• Chemical (synthetic) fertilizer
• Bio-fertilizer

Elements Needed for Plant Life

• Plants need at least 16 elements, including carbon, hydrogen, oxygen, nitrogen, phosphorus, sulfur, potassium, calcium, and magnesium.
• Plants obtain carbon from the atmosphere and hydrogen and oxygen from water; other nutrients are taken up from the soil.
• Fertilization provides plants with essential nutrients, divided into macronutrients and micronutrients (trace elements).

Macronutrients and Micronutrients

• Macronutrients: elements needed in large quantities, including [C, H, O2, N, P, K, Ca, Mg, and S).
• Micronutrients: elements needed in small quantities, including [Fe, Zn, Mn, Cu, B, and Mo].

Organic Fertilization

• Benefits of organic fertilization:
• Provides plants with their nutritional needs
• Enhances soil properties, increasing water holding capacity and aeration
• Effects of organic fertilization:
• On sandy soils: increases water holding capacity
• On clay soils: increases aeration and decreases compactness

Benefits of Humus

• Increases water holding capacity
• Is a slow-releasing source of nutrients
• Makes soil darker, increasing soil absorbance of sunlight and temperature
• Enhances aeration and soil drainage in compacted soils

Types of Organic Fertilization

• Manure: organic matter, mostly derived from animal feces, used as fertilizer in agriculture
• Classifications of manure:
  • Animal manures (e.g., cattle, chicken)
  • Guano fertilizer (excrement of seabirds or bats)
  • Compost (product of controlled biological decomposition of organic materials)
  • Green manure (crops grown and incorporated into the soil to improve soil quality)

Composting Process

• Inputs: organic materials (feedstocks) with carbon and nutrients
• Outputs: compost (humus), heat, and gases
• Key variables for controlling the composting process:
  • Type of organic matter (feedstock)
  • Carbon to Nitrogen Ratio (C:N)
  • Pile moisture
  • Pile aeration
  • Pile size
  • Temperature
  • Time

Characteristics of Compost

• Dark, loose, and crumbly texture
• Earthy smell
• Rich in nutrients
• Ready to use in about three to five months