Effect of Azospirillum lipoferum Inoculation, Previous Crop, and Usage Nitrogen on Rice (Oryza sativa L.) Growth and Yield

Incorporation of winter legume crops in rotation with rice and using plant growth-promoting rhizobacteria can be a proper alternative approach in increasing sustainable crop production in rice fields. A split factorial field experiment using randomized complete block design with three replications was conducted at the Rice Research Station of Tonekabon, Mazandaran province, Iran, in 2014 to evaluate the effects of previous crop, Azospirillum lipoferum inoculation, and N rate on growth and seed yield of rice (Oryza sativa L. cv. Shiroudi). Main plots were consisted of previous crop [berseem clover, faba bean, and control (fallow)] and subplots of Azospirillum lipoferum (Inoculated and Un-inoculated) and recommended rate of N applications (50, 75, and 100 kg.ha-1). Analysis of variance showed that rice paddy yield was significantly affected by previous crop, Azospirillum lipoferum and N rate. Result also showed that rice paddy yield was increased only by 3% when rice was planted after berseem clover as it compared with rice plant after fallow. However, rice paddy yield was significantly reduced by 16% when it was planted after faba bean as compared to that it was planted after fallow. Rice paddy yield was significantly increased by 14% after Azospirillum lipoferum inoculation. Rice paddy yield was significantly increased by 11% when N application increased from 50 to 75 kg N ha-1, and further N application (100 kg N ha-1) did not affect paddy yield significantly. Based on the result of this experiment, planting rice after berseem clover, Azospirillum lipoferum inoculation and application of kg N ha-1 of recommended rates can be used to obtain highest paddy yield in the experimental site.