Resumen
Although urea placed deep reduces nitrogen (N) loss and increases rice yield, its use is not expanding due to the lack of effective application methods. A study was carried out to determine how different urea application techniques affected the yield and nitrogen use efficiency (NUE) of transplanted Aman rice (cv. BRRI dhan46). The experiment was set up in a RCBD design with seven treatments: T1 (deep placement of urea briquettes (DPUB) by hand), T2 (DPUB by battery-powered applicator), T3 (deep placement of prilled urea (PU) briquettes by BRRI applicator), T4 (DPUB by injector applicator), T5 (DPUB by push-type applicator), T6 (broadcast application of PU), T7 (zero-N), and three replications. Findings showed that the NH4+-N concentration in field water peaked on day 3 and then rapidly fell as time passed, while the NO3--N concentration in the water and soil was minimal. T1 reported the highest grain yield, total N content and uptake, whereas T7 had the lowest values. On T1, the apparent N recovery reached its highest level (73.5%). The NUE varied from 13.26% in T3 to 29.38% in T1. Based on this finding, deep placement of urea briquette by hand is recommended for increasing the yield and NUE of T. Aman rice.