Gate Valves,Gate Valve ,Slide Gate Valve,Sluice Gate Valve WENZHOU DIYE VALVE&FITTINGS CO.,LTD , https://www.diye-valve.com
Urea is a widely used nitrogen fertilizer, but it requires careful handling to maximize its effectiveness and avoid potential harm to crops. One important consideration is that urea should not be mixed with alkaline fertilizers such as wood ash, lime, molybdenum, or magnesium phosphate. When combined, these substances can cause the nitrogen in urea to convert into ammonia, leading to significant loss through volatilization. Therefore, it's advisable to apply urea separately from alkaline fertilizers. In summer and autumn, a gap of 3–4 days is recommended, while in winter and spring, a longer interval of 7–8 days is more effective.
Another key point is that urea should not be used directly as a seed fertilizer. This is because biuret, a byproduct of urea production, can damage seeds and reduce their germination rate. Additionally, the high concentration of urea may destroy the protein structure of seeds, potentially harming the young plants. If it must be used as a seed fertilizer, it should be applied carefully, avoiding direct contact with seeds and using only small amounts.
After applying urea, it’s essential to wait before watering. Urea has low adsorption capacity in soil, meaning it can easily leach away if watered too soon. In summer and autumn, watering should be delayed for 2–3 days, while in winter and spring, waiting 7–8 days is ideal. Also, heavy rain should be avoided immediately after application, as it can wash away the fertilizer and reduce its effectiveness.
Deep application of urea is more efficient than shallow application. By incorporating it into the soil at a depth of about 10–15 cm, the fertilizer is better retained in the root zone, where it can be more effectively absorbed by plants. Studies have shown that deep application can increase urea utilization by up to 10–30% compared to surface application.
Over-application of urea can lead to waste and even crop damage. The recommended rate is generally 5–15 kg per acre for most crops, and 15–20 kg per acre for rice paddies. Excessive use may result in runoff, especially after rain, causing environmental pollution and reducing crop yield. Moreover, excess urea can seep into groundwater, increasing nitrate levels and posing risks to both human and animal health.
Foliar application of urea can be effective, but the solution must not be too concentrated. For crops like corn and rice, a 2% solution is typically safe, while vegetables and melons benefit from a lower concentration of 0.5–1.5%. Too high a concentration can burn the leaves and harm the plant.
Urea should not be applied too late in the growing season. Applying it too close to harvest time can delay crop maturity and reduce yield. It’s best to apply urea 4–7 days earlier than other nitrogen fertilizers to ensure proper nutrient uptake.
Finally, urea should not be used alone. Crops require a balanced supply of nutrients, so it's best to combine urea with organic manure and phosphorus or potassium fertilizers. This helps improve soil structure, enhances nutrient availability, and reduces nitrogen loss. For example, mixing urea with superphosphate can stabilize ammonium compounds, minimizing nitrogen loss. Combining it with organic matter also promotes faster decomposition and better absorption by plants.
By following these guidelines, farmers can make the most of urea while protecting both their crops and the environment.