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 (NO^3-).