Generally speaking, urea with a particle diameter greater than 2 mm is called large-particle urea. The difference in particle size stems from the difference in the granulation process and equipment used after the urea is produced in the factory. So, what are the similarities and differences in the application methods and fertilizer efficiency of large granular urea and small granular urea?

Similarities and differences in nature

The difference between large and small granular urea is that their active ingredients are all water-soluble quick-acting nitrogen molecules, and the nitrogen content is both 46%. From a physical point of view, the difference is that the particle size is different. Large particles of urea have lower dust content than small particles of urea, higher compressive strength, good fluidity, can be transported in bulk, are not easy to break and agglomerate, and are suitable for mechanized fertilization. This has caused differences in application methods, fertilizer efficiency, and price of different granular urea.

Application method

The same aspect is that urea is molecular nitrogen, and they are not directly absorbed by crops, and can be absorbed in large quantities only after being converted into ammonium nitrogen in the soil. Therefore, no matter the particle size of urea, the application of top dressing must be several days earlier than ammonium bicarbonate.

What should be paid attention to here is that urea particles of all sizes cannot be mixed with ammonium nitrate, sodium nitrate, ammonium bicarbonate and other highly hygroscopic fertilizers.

different places

The dissolution rate of large granular urea is slightly slower, so it is suitable for base fertilizer, but not for top dressing and flushing. Its particle size matches that of diammonium phosphate, and can be used as a material for blending compound fertilizers.

Small granular urea is suitable for various soils and various crops. It is a nitrogen fertilizer with high nitrogen content and can be used as base fertilizer and top dressing. When using small particles of urea as top dressing, it is best to apply it in strips or in acupuncture points, and try not to spread it. If it cannot be applied in strips or holes, it is best to spray before and after light rain and when the soil is moist. Do not use too much when making green fertilizer, and apply enough when making tillering fertilizer and ear fertilizer. It also has a certain effect on increasing yield when used as extra-root topdressing. Small granular urea is suitable for foliar fertilization, and its concentration is generally 0.5% to 2%.

Fertilizer efficiency difference

Small particles of urea have a large surface area, and have a large contact surface with water and soil after application, and the dissolution and release rate should be slightly faster. The dissolution and release of large granular urea in the soil is a little slower. In general, the difference between the speed of the two fertilizers is very small.

This is reflected in the application method, for example, when doing top dressing, the fertilizer effect of small granular urea is slightly faster than that of large granular urea. From the perspective of loss, the loss of large particles of urea is small, and the content of large particles of urea is low, which is beneficial to crops.

After reading these, you can understand the different characteristics of large and small granular urea! When choosing urea, whether to choose large or small particles depends on the purpose of fertilization and the different crops.