in order to investigate the effect of different levels of biological fertilizers on potato performance (cv. marfona), an experiment was carried out as strip plot based on rcb design with 3 replications in 2011 at isfahan. treatments included nitrocara at 4 levels (0: control, 220, 330 and 440 ml.ha-1) as a first factor and nitroxin+ phosphate at 4 levels (0+0: control, 20+100, 30+150 and 50+200...