Impacts of urea deep placement on nitrous oxide and nitric oxide emissions from rice fields in Bangladesh

摘要: Abstract Urea deep placement (UDP) increases nitrogen use efficiency (NUE) in lowland rice fields by reducing ammonia volatilization, surface runoff and increasing uptake. However, its effects on N losses as nitrous oxide (N 2 O) nitric (NO) are not yet clear. We conducted field experiments at two locations of Bangladesh — Agricultural University (BAU) Rice Research Institute (BRRI) to determine the UDP vs broadcast urea O NO emissions from fields. were measured three fertilizer treatments (control [0 kg N/ha], UDP, urea) using automated gas sampling analysis system continuously for growing seasons Aus (May–Aug), Aman (Aug–Dec) Boro (Jan–May). was applied 2–3 split application, while treatment, briquettes placed (7–10 cm depth) between 4 hills alternate rows meet recommended rates a single application. Treatments arranged randomized complete block design with replications measurements done every three-hour interval. sporadic event specific. Peaks observed after application urea, during dry period re-flooding soil. For rest time rice-growing season, very low negligible. across seasons, significantly (P  compared urea. Moreover, showed significant spatial seasonal variations. They higher season BAU site than that BRRI. Conversely, control similar. In contrast emissions, negligible affected treatment. variations observed, BRRI season.