OICC Press International Journal of Agricultural Management and Development 2159-5860 9 1 2019 03 01 Fertilizer Management Using Plant Growth-Promoting Rhizobacteria in Rice Fields 67 76 EN Hashem Aminpanah Department of Agronomy and Plant Breeding, Rasht Branch, Islamic Azad University, Rasht, Iran Saeed Firouzi Department of Agronomy and Plant Breeding, Rasht Branch, Islamic Azad University, Rasht, Iran Journal Article 2019 03 01 A field experiment was conducted at the Rice Research Station of Tonekabon, Iran, to determine the effect of seed inoculation with plant growth-promoting rhizobacteria on rice grain yield and yield components under different nitrogen (N) rates. The experimental design was a randomized complete block with factorial arrangement and three replicates. Factors included seed inoculation with plant growth-promoting rhizobacteria [control (un-inoculated), seed inoculation with Azospirillum lipoferum, seed inoculation with Azotobacter chroococcum, and seed inoculation with a combination of A. lipoferum and A. chroococcum] and N rates (100%, 75%, and 50% of recommended nitrogen rates, i.e., 100, 75, and 50 kg N ha-1, respectively). Results showed that the highest grain yield (7875 kg ha-1) was recorded for plants inoculated with a combination of A. lipoferum and A. chroococcum, while the lowest one was recorded for un-inoculated control plants. Moreover, rice grain yield, panicle number per m2, grain number per panicle, and 1000-grain weight increased by 9%, 9%, 18%, and 6%, respectively, as N fertilizer rate increased from 50 to 100 kg ha-1. The highest grain yield (7875 kg ha-1) was obtained when N was applied at the rate of 75 kg ha-1 to seeds inoculated with a combination of A. lipoferum and A. chroococcum.