EFFECT OF DIFFERENT DOSES OF NITROGEN FERTILIZER ON T. AMAN RICE

An experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh to evaluate the effect of source and doses of nitrogen on transplant Aman rice. Three varieties, BR11, BRRI dhan30 and BRRI dhan39 were compared at three doses of nitrogen, prilled urea @125 kg N ha^-1, USG @170 kg N ha^-1 and USG @ 70kg N ha^-1 in a randomized complete block design with three replications. USG each weighing 1 g and 2.6 g were placed manually at the depth of 8-10 cm in the middle of four hills in alternate rows at 12 days after transplanting and PU (125 kg ha^-1) splitted. Other fertilizers such as P, K, S, and Zn were applied at final land preparation. Grain and straw yields were highest (4.05 and 4.69 t ha^-1, respectively) in BR11. The highest grain yield in BR11 might be the contribution of higher number of total tillers hill^-1, grains panicle^-1, and effective tillers hill^-1. The lowest grain yield (3.55 t ha^-1) was produced by BRRI dhan30 which was the consequence of very low number of grains panicle^-1 and less 1000-grain weight. BRRI dhan39 produced the highest (101.04 cm) plant height. Effect of PU and USG significantly influenced all the yield attributes except plant height. Grain and Straw yields were highest (4.25 and 4.83 t ha^-1, respectively) from the USG 70 kg N ha^-1 (1 g/pellet). The placement of USG (70 kg N ha^-1) appeared as the best one in respect of partial factor productivity of nitrogen and agronomic efficiency of nitrogen (AEN).