As urea BAI is an organic nitrogen fertilizer, it cannot be directly absorbed and utilized by the crops after being put into soil DU soil. It can only be absorbed and utilized by the crops after being decomposed into ammonium bicarbonate under the action of DAO of soil microorganisms. The conversion rate of urea in soil is related to temperature, moisture and soil texture.

In general, in spring and autumn, the decomposition reaches a peak around 1 week, and in summer, it lasts for about 3 days. Therefore, when urea is used as topdressing, it should be considered to apply urea several days in advance.

Urea belongs to neutral fertilizer, applicable to all kinds of crops and soil, can be used as base fertilizer and topdressing, but not for planting fertilizer and rice field with fertilizer. Because urea contains high nitrogen content and a small amount of biuret, it will affect seed germination and seedling root growth.

If urea must be used as seed fertilizer, it is necessary to strictly control the amount of fertilizer and avoid contact with the seeds. For base fertilizer of 225 ~ 300 kg per hectare and for top fertilizer of 90 ~ 200 kg per hectare, soil should be applied deeply to prevent nitrogen loss. Urea is the most suitable for leaf fertilizer application, does not contain side components, easy to be absorbed by crop leaves, fertilizer effect is fast, fruit tree spraying concentration is 0.5% ~ 1.0%, in the morning or evening uniform spraying on crop leaves, in the growth period or in the middle and late stage, every 7 ~ 10 days once, spray 2 ~ 3 times. Urea can be dissolved with potassium dihydrogen phosphate, ammonium phosphate and insecticides, fungicides, spraying together, can play the role of fertilization, insecticide, disease prevention.