Study of interaction between nitrogen and biofertilizers on yield, grain growth of wheat and fertilizer use efficiency

In order to study the interaction of nitrogen and biofertilizers on yield, grain growth of wheat and fertilizer use efficiency, a factorial experiment was conducted based on randomized complete block design by three replications in field experimental University of Mohaghegh Ardabili in 2012. Factors were as follows: nitrogen rates in four levels (0, 60, 120 and 180 kg N ha-1 from Urea source) and seed inoculation with biofertilizers in five levels containing: (seed inoculation with Azotobacter chroococcum strain 5, Azospirillum lipoferum strain OF, Psedomunas putida strains of 4 and 11, control). The results showed that there was a significant difference between nitrogen rates, biofertilizers and their interaction on yield, yield components, rate and grain filling period at P ≤0.01. Comparison of means showed that the maximum yield, yield components, rate and grain filling period belonged to application of 180 kg N ha-1 whenseed inoculated with Azotobacter. Theminimum of it was observed in control treatment. The highest nitrogen use efficiency (32.1 kg/kg) was observed in 60 kg N treatment when seed inoculated with Azotobacter and the lowest of it (19.5 kg/kg) was found in 180 kg N treatment without inoculation. Grain yield and grain filling period were affected by when seeds inoculated with Azotobacter and 180 kg N was applied.