The key differences between prills and granules are:

• Size and shape: Prills are small, spherical pellets, while granules are larger and irregularly shaped.
• Handling: Prills are preferred for their uniform size, which makes them easier to handle and apply. Granules can be more variable in size and shape.
• Nitrogen release: Granules are suitable for applications that require a slower release of nitrogen, whereas the uniform size of prills allows for a more controlled release.

So in summary, the choice between prills and granules often comes down to the specific application and requirements, such as ease of handling versus desired nitrogen release rate. The different physical characteristics make them suited for different use cases.