Urea ammonium nitrate (UAN) solution is sold primarily as 28% nitrogen (N) in the Midwest, but it is also available as 30% or 32%. The lower concentration predominates due to solubility problems with higher concentrations at cold temperatures. Some 28% is applied with early weed and feed applications, then progress to 30% or 32% for later applications. UAN solutions contain 50 percent urea and 50 percent ammonium nitrate. They are comprised of 75 percent ammonium-N (NH4) and 25 percent nitrate-N (NO3), since urea is 100 percent ammonium and ammonium nitrate is 50 percent ammonium.
