An experiment was conducted at the Agronomy Field Laboratory, Bangladesh Agricultural University, Mymensingh from July to December 2014 to observe the effect of mineral nitrogen on the weed infestation and yield of transplant Aman rice. The experiment comprised three varieties viz. BRRI dhan49, BRRI dhan51 and BRRI dhan52 and five levels of nitrogen viz. 0, 40, 60, 80, and 100 kg ha–1. The experiment was laid out in a randomized complete block design (RCBD) with three replications. Variety, level of nitrogen and their interaction significantly influenced on weed infestation and yield of transplant Aman rice. The lowest weed infestation was found in BRRI dhan52 which was statistically identical with BRRI dhan49. In case of interaction, BRRI dhan52 fertilized with 60 kg N ha–l showed the best performance (3.54 t ha–1) which was as good as BRRI dhan51 (3.50 t ha–1) fertilized with 100 kg N ha–l and BRRI dhan52 (3.49 t ha–1)  fertilized with 80 kg N ha–l  with respect to grain yield. Therefore, it can be concluded that BRRI dhan52 might be grown with 60 kg N ha–l for higher grain yield.

Key words: Nitrogen, weed infestation, Transplant aman rice