Effect of weed management methods and nitrogen levels on nitrogen use efficiency of drum seeded rice

Drum seeded rice faces major challenges in achieving uniform crop establishment due to severe weed competition and inefficient nutrient utilization. Managing synchronized nitrogen supply and effective weed control remains critical for sustaining yield and profitability in this system. Keeping these points in view, a field experiment was conducted at the College Farm, PJTAU, Rajendranagar, during the rabi season of 2020–21 and 2021–22 to evaluate the impact of nitrogen levels and weed management practices on the performance of drum-seeded rice. The experiment was laid out in a factorial randomized block design with three replications, comprising four weed management practices (W1: Unweeded control, W2: Pretilachlor + pyrazosulfuron-ethyl as PE followed by penoxsulam + cyhalofop-butyl as POE, W3: Pyrazosulfuron-ethyl as PE followed by penoxsulam + cyhalofop-butyl as POE, and W4: Pretilachlor + pyrazosulfuron-ethyl as PE followed by mechanical weeding at 25 and 50 DAS) and four nitrogen levels (N1: 0 kg ha-1, N2: 75% RDN-112.5 kg ha-1, N3: 100% RDN-150 kg ha-1, and N4: 125% RDN-187.5 kg ha-1). Results revealed that 100% RDN recorded the highest agronomic efficiency and apparent nitrogen recovery, which declined at higher nitrogen levels. Conversely, 75% RDN resulted in greater physiological efficiency and partial factor productivity, suggesting improved nitrogen use efficiency at reduced application rates. Among weed management practices, integrated chemical and mechanical methods (W2, W3, W4) were more effective than the unweeded control.