Ammonia emissions from soil water of wheat field as affected by different nitrogen and irrigation strategies

摘要

Agricultural activities should be responsible for substantial amounts of ammonia (NH3) emissions. The fertilization and irrigation strategies both make great contributions to potential N losses via volatilization, but there are very few data regarding NH3 emissions as affected by the combination of application time of N fertilization and irrigation treatments. The aim of this experiment is to provide the field data on N losses due to NH3 volatilization following urea application and assess the influence of soil properties and environmental condition on emissions. The experiment including a combination of application time of N fertilization and irrigation treatments was carried out using the venting method. NH3 volatilization was monitored within 30 d following urea application. NH3 loss can fall down to the background level with irrigation or rainfall events following urea application. Otherwise, up to 30% of the N applied will be lost through volatilization. Large amounts of NH3 emissions occur only if two conditions are simultaneously satisfied: high ammonium nitrogen concentration and low soil water content in topsoil. Irrigation following urea application at jointing stage (JFI) can be adopted in the local management practice to minimize volatilization and maintain financial benefits.