Yeah, it's one of the top 5. Notice there are no numbers there.
It's hard to find numbers, most places basically ignore the usage as a direct fertilizer. It seems to be much more popular on the US than anywhere else, for the US I was able to find this (it's old, but it's what I have):
> Urea is the most popular source of dry N fertilizer, accounting for 79% of the
total dry N used. Ammonium sulfate has risen in popularity. In 1988 it constituted 14% of the dry N market. (https://www.canr.msu.edu/field_crops/uploads/archive/E0896.p...)
Most countries just equate nitrogen fertilizer with urea.
It's hard to find numbers, most places basically ignore the usage as a direct fertilizer. It seems to be much more popular on the US than anywhere else, for the US I was able to find this (it's old, but it's what I have):
> Urea is the most popular source of dry N fertilizer, accounting for 79% of the total dry N used. Ammonium sulfate has risen in popularity. In 1988 it constituted 14% of the dry N market. (https://www.canr.msu.edu/field_crops/uploads/archive/E0896.p...)
Most countries just equate nitrogen fertilizer with urea.