Abstract:
Insufficient Nitrogen (N) supply is an important constraint to productivity of lowland rice (Oryza sativa L.), and there is limited information available on optimum timing of N fertilizer application for lowland rice production in Fogera plain. To determine the effects of appropriate timing of nitrogen fertilizer application for efficient use of the nutrient for optimum yield, a field experiment was conducted on Vertisol of Fogera Plain in 2016/2017 cropping season under rain fed conditions. Recommended fertilizer rates of 69/23 kg N/P2O5 ha-1was used in the experiment. The Nitrogen was applied in seven different splits. These were:- (T1) 1/2 at sowing + 1/2 at tillering representing the control, (T2) 1/3 at sowing + 2/3 at tillering , (T3) 1/3 at 15 days after sowing + 2/3 at panicle initiation, (T4) 1/3 at 25 days after sowing + 2/3 at panicle initiation, (T5) 1/3 at sowing + 1/3 at mid tillering + 1/3 at panicle initiation, (T6) 1/3 at 15 days after sowing +1/3 at panicle initiation +1/3 at heading and (T7) 1/3 at 25 days after sowing + 1/3 at panicle initiation +1/3 at heading. The treatments were laid out in RCBD with three replications. The results of the present experiment showed that most of the yield and yield components significantly affected by the time of N application. Maximum plant height, panicle length, number of total tillers and number of effective tillers, the maximum number of filled spicklets per panicle, and the least number of un-filled spicklets per panicle were recorded when 1/3 of N was applied at 25 days after sowing and 2/3 at panicle initiation. The stated treatment resulted in the highest biological and straw yields. The highest mean grain yield (3.5 ton/ha) was recorded when N was applied 1/3 at 25 days after sowing and] 2/3 at panicle initiation, followed by N application 1/3 at 15 days after sowing +1/3 at panicle initiation +1/3 at heading which yield 3.2t/ha of rice. Comparing with other treatments, the Nitrogen Use Efficiency (NUE) was found to be higher when 1/3 of N was applied at 25 days after sowing + 2/3 at panicle initiation. Based on correlation analysis in this experiment, grain yield of rice had strongly significant positive correlation with yield and yield component parameters. This indicated that grain yield had direct relationship to yield attributes of rice Therefore, it can be concluded from this result that the nitrogen applied 1/3 at 25 days after sowing plus 2/3at panicle initiation is the best appropriate time for rice production in Fogera plain. However; as this is a one year result, further testing is required to put the recommendation more stronger