Effect of phosphorus rate, Rhizobium phaseoli inoculation and Nitragin biofertilizer on growth and yield of common bean (Phaseolus vulgaris L.)

A field experiment was conducted in Amlash, Guilan province to evaluate the effect of phosphorus rate (P), Rhizobium phaseoli inoculation and nitragin biofertilizer on growth and yield of common bean (Guilan landrace). The experiment was designed in a factorial arrangement based on a Randomized Complete Block Design with three replicates. The factors were P rate, Rhizobium phaseoli application, and application of nitragin biofertilizer. Result showed that grain and fresh pod yields were significantly increased by 28% and 21%, respectively, as P application rate increased from 0 to 50 kg ha-1. No significant increase in grain and fresh pod yields were observed as P application rate increased from 50 to 75 kg ha-1, but further increase in P rate (75 kg ha-1) reduced grain and fresh pod yields significantly. Regression analysis showed that the highest grain (1403.9 kg ha-1) and pod (8510.7 kg ha-1) yields were obtained when phosphorus was applied at the rate of 65.4 and 59.3 kg ha-1, respectively. Grain and fresh pod yields were significantly increased by 7 and 10% with nitragin biofertilizer application, respectively. Moreover, grain and fresh pod yields increased by 17% and 20% after Rhizobium inoculation.