Effect of liquid and cyst formulations of Azospirillum with inorganic nitrogen on the growth and yield of rice

The nitrogen-fixing rhizobacterium Azospirillum lives in close association with plant roots, where it exerts beneficial effects on the plant growth and yield of many crops of agronomic importance. As carrier-based inoculants have a short shelf life and poor quality, new liquid and cyst formulations of inoculants have been developed and standardized for Azospirillum . In the present investigation, experiments were conducted to study the effect of liquid and cyst formulations of Azospirillum , combined with inorganic nitrogen, on the growth and yield of rice. Inoculation with the cyst formulation of Azospirillum enhanced the plant height, biomass and N uptake of the plants, the available nitrogen content of the soil and the yield of rice to the greatest extent when compared to carrier-based Azospirillum , followed by the liquid formulation. The results of the present study clearly indicated that the cyst and liquid formulations of Azospirillum could be used as bioinoculants more effectively than the carrier-based one.