The core of improving the effectiveness of urea application lies in reducing nitrogen loss (such as volatilization, leaching, denitrification) and enhancing crop absorption and utilization efficiency. The following are specific technical measures:
1. Deep application of soil cover (the most critical measure)
Urea surface application can easily cause ammonia volatilization loss.
Dryland: Adopt trench or hole application, with a depth of 10-15 centimeters. Immediately cover and compact the soil after application to keep the fertilizer in a moist soil layer and reduce contact with the air.
• Paddy field: After application, maintain a shallow water layer (3-5 cm) and mix fertilizers into the mud in conjunction with tillage. Avoid drainage and wait for 3-5 days for the conversion to ammonium nitrogen before restoring normal water layer management.
2. Split application (small amount multiple times)
Urea has strong mobility in soil and can easily cause leaching losses when applied in large quantities at once.
Principle: According to the fertilizer requirements of crops, the total amount of nitrogen fertilizer should be divided into base fertilizer, tillering fertilizer, ear fertilizer, etc. and applied multiple times.
Benefits: It not only meets the needs of different growth stages of crops, but also reduces the amount of single application and minimizes nitrogen residue and loss in the soil.
3. Apply in advance (considering conversion time)
Urea needs to be converted into ammonium nitrogen in order to be absorbed in large quantities, and the conversion is affected by temperature.
• Early stage: 4-7 days earlier than the peak period of crop fertilizer demand (7-10 days earlier in low temperature and 2-3 days earlier in high temperature), ensuring synchronous supply and demand of fertilizers.
4. Foliar spraying (auxiliary method)
Foliar spraying can directly supplement nitrogen during the late stage of crop growth or when the root absorption capacity decreases.
• Concentration: Control at 0.5% -2.0% (depending on the crop type) to avoid burning the leaves.
• Time: Early morning or evening, avoid high temperatures at noon.
• Efficiency enhancement: It can be mixed and sprayed with potassium dihydrogen phosphate and trace element fertilizers to achieve nutrient complementarity.
5. Apply other fertilizers in combination (balanced fertilization)
Combination of nitrogen, phosphorus, and potassium: Single application of urea can easily lead to excessive crop growth and poor stress resistance. Combined with the application of phosphorus and potassium fertilizers, it can coordinate nutritional growth and reproductive growth, and improve fertilizer utilization efficiency.
• Adding organic fertilizer: Organic fertilizer can improve soil structure, increase soil colloid quantity, enhance soil nitrogen retention capacity, and reduce urea leaching.
6. Apply urease inhibitors or nitrification inhibitors
Urease inhibitors, such as hydroquinone and phenylphosphoramide (PPD), can delay urea hydrolysis and reduce ammonia volatilization.
Nitrification inhibitors, such as dicyandiamide (DCD) and 3,4-dimethylpyrazole phosphate (DMPP), can inhibit the conversion of ammonium nitrogen to nitrate nitrogen, reducing leaching and denitrification losses.
• Choose high-efficiency urea: directly purchase “stable urea” with the above-mentioned inhibitors added.
7. Avoid mixing with alkaline fertilizers
Mixing urea with alkaline fertilizers (such as lime, plant ash, calcium magnesium phosphate fertilizers, etc.) can accelerate ammonia volatilization.
If cooperation is required, the application time should be staggered, with an interval of 3-5 days or more.
8. Control the content of biuret
Biuret is toxic to crops and can inhibit seed germination and seedling growth.
When purchasing urea, strictly check the content of urea (generally required to be ≤ 1.0%) to avoid using inferior urea with excessive urea.
9. Timely water control
After applying urea to dry land, timely irrigation should be carried out in case of drought, but excessive flooding should be avoided to prevent urea from leaching deep into the roots with water; Waterfields should avoid long-term deep water layers to prevent denitrification and denitrification.
10. Summary
The mnemonic for improving the effectiveness of urea application:
Deep application of soil cover to prevent volatilization, early application and other transformations;
Adding a small amount of phosphorus and potassium multiple times, and adding bacterial fertilizer has a better effect;
Inhibitors can help, don’t forget them when it’s time to control water.
Post time: Feb-04-2026