Types of sustained-release urea

The English name for slow-release urea is Slow release urea. It is a highly effective nitrogen fertilizer; its nitrogen utilization efficiency increases by 10 percentage points, and it is produced by adding environment-friendly slow-release agents to the urea manufacturing process. Determination of urea content in sustained-release urea by p-dimethylaminobenzaldehyde spectrophotometry

The principle of slow-release urea is to add environment-friendly inhibitors during the production process in urea manufacturing, in accordance with specific technical requirements, thereby converting ordinary urea products into slow-release urea. The effective period of fertilizer efficacy has been extended from 40–50 days to 110–120 days; it is possible to apply the base fertilizer once only, eliminating the need for additional fertilizations, while continuous oxygen supply is provided throughout the crop’s growth period ； The nitrogen utilization rate increased by an average of 10 percentage points ； Crop yields increase by 8%-15% ； Under equal yield conditions, fertilizer use can be reduced by about 15%. Synthetic slow-release nitrogen fertilizers mainly include urea formaldehyde (UF), isobutyryl diurea (IBDU), butenyl diurea (CDU), sulfur-coated urea (SCU), and polymer-coated fertilizers. The fertilizer wrapped in an encapsulating film can be urea or a compound fertilizer; the fertilizer is covered by sulfur or polymer materials, and nutrients are released only when water diffuses into the film and dissolves the fertilizer. The rate of nutrient release can be controlled by the thickness of the membrane and the number of pores on it; therefore, particles with varying membrane thicknesses are often mixed together to achieve uniform nitrogen release.