The effect of nitrogen fixation and phosphorus solvent bacteria on growth physiology and vitamin C content of Capsicum annum L. HalehTayeb Rezvani1, Pezhman Moradi2* and Foruzandeh Soltani3

In order to study the effects of biofertilizers on yield quantity and quality of Capsicum annuum L., an experiment was conducted in completely randomized block design with three replications in 2011. All plants were treated before transplanting in pots in greenhouse condition by biological fertilizers including nitroxin and biophosphates. Treatments included 3 concentrations of nitroxin (1:3, 1:5 and 1:7) diluted by water, 2 levels of biophosphate fertilizer (inoculated and non- inoculated plants) and NPK (2:6:1.5 g per pot) fertilizer.  The control group had no treatment of chemical and biofertilizer. Results revealed that the highest yield (3177.85 g/plant) dry weight and fresh weight (5.43 g and 120 g) respectively, were obtained by nitroxin 1:5 combined with phosphate solubilizing bacteria treatment. This combination of biofertilizers (nitroxin 1:5 and biophosphate) significantly improved leaf phosphorous and nitrogen content, 0.27% and 2.16%, respectively. Calcium content of fruits treated by nitroxin and biophosphate also showed considerable increase (0.33%). Vitamin C content was enhanced in combined treatments of nitroxin 1:5 and 1:3 with biophosphate. Application of low concentrations of nitroxin and biophosphate made no significant difference with control plants. Based on this investigation the best fertilizer concentration and combination for sweet pepper production in greenhouse condition was nitroxin 1:5 together with biophosphate fertilizer.