Liquid Ammonium Nitrate, commonly referred to as UAN (Urea-Ammonium Nitrate Solution), is a popular liquid nitrogen fertilizer widely used in agriculture. It is a mixture of urea and ammonium nitrate dissolved in water, providing a versatile and efficient source of nitrogen for crops.

Chemical Composition

• Typical Nitrogen Content:

  • UAN solutions are usually available in three concentrations:
    • UAN-28: 28% nitrogen by weight.
    • UAN-30: 30% nitrogen by weight.
    • UAN-32: 32% nitrogen by weight.
  • The nitrogen is supplied in three forms:
    • Urea: 50% (readily available nitrogen).
    • Ammonium Nitrate: 50% (half as ammonium, half as nitrate).

• Physical State:

  • Clear liquid, easy to handle and mix with other products.

Applications in Agriculture

1. As a Fertilizer

• UAN provides nitrogen in both immediate and slow-release forms, enhancing crop growth.
• Commonly applied to row crops like corn, wheat, and soybeans.

2. Compatibility with Other Inputs

• Can be blended with other nutrients (e.g., potassium or phosphorus) or crop protection chemicals.
• Often used in fertigation or sprayed on crops.

3. Timing of Application

• Pre-Planting: Incorporated into the soil before planting to boost initial nitrogen levels.
• Side-Dressing: Applied during crop growth to meet the nitrogen demands of plants.

Advantages of UAN

1. Efficient Nitrogen Source:

   • Supplies three forms of nitrogen: urea (immediate), ammonium (moderate), and nitrate (quick-release).

2. Ease of Application:

   • Can be applied via spray equipment, irrigation systems, or directly onto the soil.

3. Mixing and Storage:

   • Compatible with pesticides, herbicides, and other liquid fertilizers, reducing the number of field passes.

4. Reduced Volatilization:

   • Compared to urea alone, UAN is less prone to nitrogen loss as ammonia gas.

Disadvantages

1. Handling and Storage:

   • Requires corrosion-resistant tanks and equipment due to its slightly acidic nature.

2. Cost:

   • Typically more expensive per unit of nitrogen compared to granular fertilizers.

3. Weather Sensitivity:

   • Efficiency depends on weather; heavy rain can wash away nitrogen before absorption.

Environmental Considerations

• Excessive use can lead to nitrogen leaching into groundwater or runoff into water bodies, causing environmental issues like eutrophication. Proper application rates and timing are crucial.

Liquid Ammonium Nitrate (UAN) is an efficient and versatile fertilizer for modern agriculture, offering ease of application and a reliable nitrogen source for crops. However, its benefits must be balanced with proper handling, storage, and environmental management practices.