A review on management of urea fertilizer to minimize losses of nitrogen from rice fields

Volatilization of NH3 from urea and other N fertilizers is controlled by a number of diverse soil properties and environmental conditions that make losses difficult to predict in the field. In general, higher pH, temperature, crop residue, and moisture conditions increase the potential for volatilization, while increased incorporation depth from tillage, rain, or irrigation decrease volatilization potential. Due to soil characteristics such as high Cation Exchange Capacity and buffering capacity, substantial inputs of bicarbonates and Ca on irrigated land, and generally cool conditions during major fertilizer application periods, the potential for substantial urea volatilization in many cropping systems of the is likely relatively low. Nevertheless, the lack of direct field measurements of NH3 volatilization is coupled with the complexity of fertilizer management practices for the many diverse crops grown in the area is reason to exercise caution and use good urea management practices. Understanding the factors that influence volatilization will allow urea users to select management practices that minimize volatilization.