UNIT 11: Fertilizer Application

Success Criteria

• Apply fertilizers to crops correctly.
• Identify types of fertilizers.
• Explain methods of applying fertilizers in a crop field.
• Calculate rates of fertilizer application.

Types of Fertilizers

• 23:21:0+4S (DAP): Applied during planting or soon after germination (basal dressing).
• Calcium Ammonium Nitrate (CAN) or Urea: Applied 3 to 4 weeks after germination (top dressing).

Methods of Fertilizer Application

• Broadcasting: Fertilizer is spread throughout the field. For manure, it’s incorporated into the soil during ploughing. Common in rice farming.
• Dollop or Drilling: Holes (7-10cm from plants) are made, and fertilizer is applied using a measuring cup.
• Foliar: Liquid fertilizer is applied to crop leaves.
• Injection: Liquid fertilizer is injected directly into the soil.
• Irrigation: Fertilizer is mixed with irrigation water.

Fertilizer Application Rates (Example)

Factors to Consider Before Applying Fertilizer

• Soil analysis (to determine nutrient levels).
• Soil pH (to select appropriate fertilizer type).
• Soil moisture.
• Application method.
• Timing of application.
• Quantity and cost of fertilizer.

Fertilizer Grade Analysis

• It is the process of determining the amount of each specific nutrient in a fertilizer.

Fertilizer Ratio

• Formula: Percentage (%) = (Nutrient content / Total weight of fertilizer) x 100
• It is a relative percentage of nutrients in a fertilizer, expressed as a ratio.
• Legumes (e.g., groundnuts) often don’t need fertilizer because their root nodules contain nitrogen-fixing Rhizobium bacteria. This is particularly relevant for compound fertilizers like 23:21:0 + 4S.