There are a few points to note about the use of urea:
1, Do not spread it directly on the ground, and do not use it when the soil is dry, otherwise a large amount of nutrients will evaporate and be lost in vain, or the ammonia volatilized by urea will cause seedling burn. If urea is spread in the field, the agricultural technology backpack recommends that you spread it before the rain. The rain here refers to a light and moist rain, not a heavy rain. A light rain can bring urea into the soil, and a heavy rain will only wash the urea into the ineffective deep soil.
2, Do not irrigate immediately after fertilization, otherwise a large amount of nutrients in urea will be lost to the soil below the tillage layer with water and reduce the fertilizer efficiency. The correct way to use it is to use it when the soil in the field is moist. When applying fertilizer, cover the urea with soil and apply it to a deep soil of 15-25 cm. In short, urea should be used deep rather than shallow.
3, It is recommended to use urea about 6-8 days in advance in winter and early spring low temperature seasons, about 2 days in advance in summer high temperature seasons, and about 3-4 days in advance in warm spring and autumn seasons.
4, Do not use excessive urea, otherwise it is easy to cause a large amount of fertilizer waste, and it is also easy to cause excessive growth of crops, a large number of lodging, burning roots and seedlings, increased pests and diseases, and reduced yields and quality.
5, When using urea, it can be mixed with acidic fertilizers such as potassium sulfate and superphosphate (the fertilizer efficiency is not reduced), but it is not suitable to mix it with alkaline fertilizers such as calcium magnesium phosphate and wood ash, otherwise the nitrogen in the urea will be converted into ammonia and volatilized and lost. When urea is used with alkaline fertilizers, it is recommended to use them separately at an interval of 5-7 days.