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Classification and characteristics:
There are many processes for urea production, but the commonly used methods are the aqueous solution full circulation method, the carbon dioxide stripping method, and the ammonia stripping method. No matter which of these three processes is used, they have common characteristics: First, the most important corrosive medium is urea methylammonium liquid, and liquid ammonia, ammonia, carbon dioxide, urine, ammonium bicarbonate, water, steam, and other corrosive properties Lighter medium; second, the operating temperature and pressure in the urea synthesis tower, one of the core equipment for urea production, are relatively high, which creates objective conditions for stress corrosion.
Urea is a white granular fertilizer with high nitrogen content and stable chemical properties. It has no adverse effects on the soil when used throughout the year. It is important agricultural nitrogen fertilizer. But do you know that area, which seems “no shortcomings” like this, cannot be directly absorbed by crops?
Why do we need to apply urea before watering in agricultural production?
As an organic solid fertilizer, urea is absorbed by crops in a complicated process. After urea is applied to the soil, it needs to be hydrolyzed into ammonium nitrogen by the action of soil urease under proper pH, temperature, and moisture conditions before it can be absorbed and utilized by crops. In the whole process, the role of urease cannot be ignored, because the rate of hydrolysis and conversion of urea is closely related to the activity of soil urease. Generally, the higher the soil urease activity, the faster the rate of urea hydrolysis and conversion.
In agricultural production, urea is usually applied first and then watered. This is because irrigation can leached urea to a certain depth in the soil. The greater the amount of water, the deeper the leaching depth. This will not only make urea stay in the soil in a molecular state for a longer time but also as the water evaporates, the urea stored in the deep layer of the soil will move up to the surface and then decompose.
Urea, as a fertilizer that is currently used in a large amount, has many advantages. Firstly, urea has a relatively high fertilizer content, and its nitrogen content has reached 46.65%, which is more than double that of ammonium sulfate; secondly, the use of urea will not have side effects on the soil; secondly, because urea does not contain harmful plants The ingredients, even if they are randomly scattered on the leaves, will not cause damage to the plants, and it is more convenient to use.
Although chemical fertilizers are very helpful to the growth of crops, it is necessary to control the dosage and adjust the usage when using it. Excessive use of chemical fertilizers will reduce the content of soil organic matter, resulting in soil compaction, and if the structure of chemical fertilizer application is not complete, there will be excess nitrogen, potassium deficiency, or phosphorus abundance.
Urea has a wide range of uses. It can not only play a role in agriculture but is also involved in animal husbandry and industrial production. I believe that in the near future, urea will definitely play more value.