The experiment was carried out using two factors completely randomized experimental design with four replications per treatment. The first factor included two rice varieties (KInu, Hananomai) and second factor included five nitrogen sources [For control (no nitrogen), 0.2 g N/pot of Dau Trau Golden N 46A+(urea nitrogen coated with Agrotain active element, content from 0,2 to 0,3 percent), 0.1 g N/pot of Dau Trau Golden N 46A+ (urea nitrogen coated with Agrotain active element,content from 0.2 to 0.3 per cent) combined biofertilizers containing nitrogen-fixing bacterium Azospirillum lipoferum, 0,2 g N/pot urea nitrogen and 0,1 g N/pot urea nitrogen combined biofertilizers containing nitrogen-fixing bacterium Azospirillum lipoferum. Results dermined that when applied to the 0,1 g N/pot (equivalent to 40 kg N/ha) of Dau Trau Golden N 46A+ combined biofertilizers containing nitrogen-fixing bacterium Azospirillum lipoferum incresed plant height, number shoots and yield componets . This nitrogen source also obtained the highest yield (25,73 g/pot).