What are the uses of urea?

Urea is a crop fertilizer that often needs to be applied. Its main function is to not leave any harmful substances in the soil, and long-term application has no adverse effects. In industry, liquid ammonia and carbon dioxide are used as raw materials to directly synthesize urea under high temperature and high pressure conditions. In addition to being used as a chemically synthesized fertilizer, urea can also be used in large quantities for other chemical products, medicines, food, dye solvents, moisture absorbents, and viscose fiber expanders , Resin finishing agent, diesel engine exhaust gas treatment fluid and other production materials.

Precautions in the use of urea:

1. Urea is suitable for base fertilizer and top dressing, and sometimes as seed fertilizer. It is suitable for all crops and all soils. It can be used as base fertilizer and top dressing. It can be used in dry paddy fields. In alkaline or alkaline soils, urea is hydrolyzed to generate ammonium nitrogen, and surface application will cause ammonia volatilization, so deep cover soil should be applied.

2. After urea is sprayed on the surface of the paddy field, the ammonia volatilization after hydrolysis is 10%-30%. In alkaline soil, the nitrogen loss by ammonia volatilization is 12%-60%. Under high temperature and high humidity, the ammonia volatilization of urea can burn plants and accelerate the nitrification rate. Therefore, it is very important to apply urea deeply and use water to carry fertilizer.

3. Because urea can accumulate a large amount of ammonium ions in the soil, it will increase the pH by 2-3 units. In addition, urea itself contains a certain amount of biuret. When its concentration is 500ppm, it will affect the crops. Roots and sprouts have inhibitory effects, so urea is not easy to be used as seed fertilizer, seedling fertilizer and foliar fertilizer. The urea content in other application periods should not be too much or too concentrated. After the seedling stage crops are damaged by biuret, the chlorophyll synthesis barriers are formed, and the leaves appear chlorosis, yellowing and even whitening patches or stripes.

4. Urea cannot be mixed with alkaline fertilizers. After urea is applied, it must be converted into ammonium nitrogen before it can be used by crops. Under alkaline conditions, most of the nitrogen in ammonium nitrogen will become ammonia and volatilize. Therefore, urea cannot be combined with plant ash, calcium magnesium phosphate fertilizer, carbon Mixed or simultaneous application of alkaline fertilizers such as ammonium.

What is the effect of urea on plant growth and how to use it?

1. The role of urea is to adjust the amount of flowers. 5-6 weeks after flowering, spray 0.5% urea water solution on the leaf surface for 2 times, which can increase the nitrogen content of the leaves, accelerate the growth of new shoots, inhibit the differentiation of flower buds, and make the The annual flower quantity is appropriate.

2. Prioritize the main crops. When applying, the crops with larger planting area and higher economic value (such as wheat and corn) should be considered first. For secondary crops such as buckwheat, you can use less application according to your own economic situation. Or even do not apply it, and give full play to the effect of fertilizer in increasing production. Use as base fertilizer or top dressing. Urea is suitable for use as base fertilizer and top dressing. Generally, it is not used as seed fertilizer.

3. Apply in advance. After urea is applied to the soil, it is first hydrolyzed into ammonium bicarbonate by the action of soil microorganisms before it can be absorbed by crop roots. Therefore, it should be applied in advance. Apply urea after rain as much as possible to have good moisture absorption performance. When applying topdressing in dry land, try to arrange it after rain so that the fertilizer can be quickly dissolved and absorbed by the soil.
4. If urea is stored improperly, it will easily absorb moisture and agglomerate, which will affect the original quality of urea and bring certain economic losses to farmers. This requires farmers to store urea correctly. Be sure to keep the urea packaging bag intact before use, handle it with care during transportation, avoid rain, and store it in a dry, well-ventilated place with a temperature below 20 degrees.

5. If it is a large amount of storage, use a wooden square to padded the bottom about 20 cm, and leave a space of more than 50 cm between the upper part and the roof to facilitate ventilation and moisture, and leave aisles between the stacks. To facilitate inspection and ventilation. If the urea that has been opened in the bag is not used up, the bag opening must be sealed in time to facilitate use next year.


Post time: Jul-06-2021