AimsThis study aimed to evaluate the efficiency of four phosphate-solubilizing bacteria (PSB) on the growth and yield of rice under different soil conditions. MethodsBacterial strains were Rahnella aquatillis (), Enterobacter sp. (), Pseudomonas fluorescens and Pseudomonas putida. These studies were conducted on different rice cultivars (Shiroodi', Tarom' and Tarom Hashemi') in both pot and field experiments. Measurements started from transplanting and continued throughout the growing season in field experiments. ResultsSingle PSB inoculations in field trials increased grain yield, biological yield, total number of stemshill(-1), number of panicleshill(-1) and plant height by 850-269%, 124-309%, 203-387%, 221-361% and 085-335% in experiment 1, by 774-147%, 422-126%, 667-167%, 40-154% and 315-420% in experiment 2 and by 234-37%, 161-364%, 302-391%, 288-34% and 211-455% in experiment 3, respectively, compared to the control. Our results indicate that the application of triple super phosphate together with PSB inoculations resulted in reducing the use of chemical fertilizers (about 67%) and increasing fertilizer use efficiency. ConclusionsThis study clearly indicates that these PSBs can be used as biofertilizers in ecological rice agricultural systems. Significance and Impact of the StudyTo the best of our knowledge, this is first report on the association of Rahnellaaquatilis with rice and also the application of a mathematical model to evaluate the effect of PSBs on rice growth.