Urea and Phosphate Interactions in Fertilizer Microsites: Ammonia Volatilization and pH Changes

Ammonia volatilization from urea fertilizer reduces N fertilizer efficiency by crops. Reduction of NH3 loss may be possible through addition of acidic materials. The objectives of this study were to compare the effects of three phosphate fertilizers on NH3 volatilization, urea hydrolysis, and pH changes with surface-applied urea. Surface soil samples from two Typic Humaquepts, a Ste Rosalie clay (very-fine-silty, mixed, acid, frigid) and an...