Assessment of Nitrogen Sources and Management for Sustainable Nitrogen Use in Subtropical Conditions: A Varietal Performance Study on Rice and Weed Growth

When growing rice, nitrogen (N) is the most vital component since it determines how much grain the crop will produce. Among the many causes of rice’s low productivity, improper nitrogen supply and inefficient nitrogen use are thought to be an important issue. In order to ensure sustainable N-management as well as to lower N-losses, it was decided to investigate how various rice cultivars react to both organic and inorganic nitrogen sources, as well as how weed infestation behavior changes with these sources in boro rice fields. Five distinct fertilizer combinations, including the control, were tested in an entirely block design that was randomized and had three replications. Each of the following sources of N: urea (prilled) at 100% of the RD (N 100PU ), poultry manure at 100% of the RD (N 100PM ), urea at 50% of the RD + poultry manure at 50% of the RD (N 50PU+50PM ), and urea super granule at 100% of the RD (2.7 g per 4 hills) (N USG ) were administered on BRRI dhan29, BRRI dhan88, BRRI dhan92 and BRRI dhan96, respectively. It is observed that N 50PU+50PM was beneficial for weed among the nitrogen sources. But comparatively less weed invasion was noticed in the N USG treated plots next to control specially in BRRI dhan29. With the use of N USG , all of the varieties tested in this experimentation generated greater grain yield than they did with the use of the other nitrogen sources. When treated with N USG , BRRI dhan29 showed a rise in grain yield around 64.34% and a greater nitrogen utilization efficiency compared to control. When benefit cost ratio (BCR) is considered, both the BCR and net income were the highest for the BRRI dhan29 variety while N USG was employed. Finally, it can be inferred that, in comparison to other sources, the combination of BRRI dhan29 with application of N USG appeared as the promising combination in order to increase grain production while improving nitrogen use efficiency, greatest BCR and to lessen the infestation of weeds throughout the boro season.