Ammonia Assessment in Irrigated Rice System after Nitrogen Fertilizers Application

Abstract

Nitrogen fertilization is widely used in irrigated rice fields in Burkina Faso, but its efficiency is very low due to the N-based greenhouse gas emitting traditional management practices. Urea deep placement (UDP) in lowland rice fields is one of the best currently applicable management techniques to mitigate N emissions while increasing N use efficiency. Floodwater ammonia concentration was quantify under irrigated rice field fertilized with N fertilizers prilled urea (PU) and briquettes-urea super granules (USG). Field experiments were carried out in Sourou valley in Burkina Faso in the wet season of 2012 and dry season of 2013. PU was broadcast and USG were point-placed deeply into the soil at 5-7 cm. Full rate (52 kg N ha-1) of USG was applied and half rate of PU (29 kg N ha-1) was applied. The concentrations of ammonium in the floodwater and the pH values were collected ten days after urea application was shown to be high with PU than USG. The use of USG reduced ammonium accumulation in the floodwater by 18 to 37% relative to the application of PU. Highest pH values were observed with the use of PU compared to USG. USG technology can reduce N accumulation in floodwater and thereby limit N losses in floodwater and N emissions into the atmosphere.