The best time to apply urea fertilizer is generally during the early morning or late afternoon/early evening.
Here's why timing matters and how it affects urea application:
Urea is a widely used nitrogen fertilizer, but it's susceptible to nitrogen loss if not applied correctly. This loss primarily occurs through a process called volatilization, where urea converts to ammonia gas, which then escapes into the atmosphere. Several factors influence volatilization, and timing plays a crucial role.
Factors Influencing Urea Application Timing:
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Temperature: High temperatures accelerate the volatilization process. Applying urea during the hottest parts of the day significantly increases nitrogen loss. Early morning or late afternoon/early evening applications avoid peak temperatures.
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Sunlight: Direct sunlight can also contribute to urea breakdown and subsequent nitrogen loss. Applications during cooler, cloudier times of day minimize this effect.
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Moisture: Moisture is crucial for urea to dissolve and move into the soil, where it's less vulnerable to volatilization. Ideally, apply urea before a light rain or irrigation. If this isn't possible, incorporate the urea into the soil (tillage) to protect it.
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Soil pH: High soil pH increases volatilization. In alkaline soils, applying urea when temperatures are cooler becomes even more critical.
Best Practices for Urea Application:
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Apply in the Early Morning or Late Afternoon/Early Evening: This helps avoid high temperatures that contribute to nitrogen loss through volatilization.
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Incorporate into the Soil: If possible, till the urea into the soil immediately after application. This physically protects the urea from the atmosphere and encourages its conversion to ammonium, a more stable form of nitrogen.
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Apply Before Rain or Irrigation: Moisture helps dissolve the urea and move it into the soil. Avoid heavy rainfall immediately after application, as this can lead to runoff and nutrient loss.
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Use a Urease Inhibitor: Urease inhibitors slow down the conversion of urea to ammonia, giving it more time to move into the soil. This can significantly reduce nitrogen loss, especially in warm, dry conditions.
Summary
Applying urea fertilizer strategically, particularly during cooler parts of the day or before rain, and considering soil conditions, will improve nitrogen uptake and minimize losses, leading to more efficient fertilizer use.
