Urea, the solid fertilizer with the highest nitrogen content (46 percent), dominates.[28] Recently, it has accounted for about 55 percent of all nitrogen applied to the world’s fields, and it is widely used in Asia to support the rice and wheat harvests of China and India—the world’s two most populous nations—and to guarantee good yields in five other Asian countries with more than 100 million inhabitants.[29] Less important nitrogenous fertilizers include ammonium nitrate, ammonium sulfate, and calcium ammonium nitrate, as well as various liquid solutions.
