Urea

The urea fertilizer, also popularly called forty six zero zero (46-0-0), is a simple or straight (single-element) fertilizer that supplies the major essential element nitrogen in ammonic form (NH₄⁺). The positively charged ammonium ion (NH₄⁺) is nonvolatile and is one of the two forms of nitrogen that can be absorbed by plants, the other being nitrate (NO₃^–).

Urea can be applied in the soil in the form of solid granules or prills, or pellets. The most dominant formulation is the white, crystalline granule. The prills used to be the primary form of urea, but they have been surpassed by granules which are larger, harder, and more stable under high humidity. Urea can also be dissolved in water and used as a soil drench or otherwise distributed with irrigation water or applied as foliar spray.