Why is urea preferred over ammonium bicarbonate and ammonium carbonate in agriculture?

Why is urea preferred over ammonium bicarbonate and ammonium carbonate in agriculture?
Urea carries over 46% nitrogen, the highest among solid nitrogen fertilizers, which cuts handling, storage and freight cost per unit of nutrient. Ammonium bicarbonate emerged in China because early coal gasification and weak equipment manufacturing favored small and medium nitrogen plants, but it decomposes easily and has low nutrient density. As imported and large-plant urea displaced it from the 1980s, domestic output shifted decisively to urea. Ammonium sulfate risks soil compaction and competes for sulfuric acid, while ammonium chloride is limited by chlorine-sensitive crops. Ammonium nitrate, once a rival, is constrained by explosion safety rules.