Understanding Factors Controlling Ammonia Volatilization from Fertilizer Nitrogen Applications 

Nitrogen is the soil nutrient needed in the largest quantity by plants. Because most plants cannot make or ""fix"" nitrogen on their own, it must be applied as fertilizer, most often in the forms of ammonium (NH4), nitrate (NO3) and urea (CO(NH2)2) or some combination of those. However, urea and other NH4-forming fertilizers are susceptible to loss as NH3 gas, particularly when left on the soil surface after application. This publication discusses the factors and mechanisms that influence ammonia volatilization so growers may select the best management practices to minimize NH3 volatilization and to maximize their cropping system's sustainability.