Effects of biological fertilizers on yield and concentration of micronutrients in organs of tomato under cadmium stress

Soil pollution by heavy metals is a serious environmental problem all over the world that may damage to human and ecosystem health. An experiment was aimed to assess the effects of biological fertilizers on yield and yield components of tomato under cadmium stress. This experiment was factorial and had a completely randomized design and three replications. Three combinations of biological fertilizers include M1: Azotobacter bacteria㌧⢮롢충 fungi ̺ⲥ陘 bacteria, M2: Mycorrhizal fungi Bacillus bacteria Pseudomonas bacteria Azotobacter bacteria, M3: Pseudomonas bacteria Azotobacter bacteria Mycorrhizal fungi and M0: treatment without biological fertilizers (control).The levels of soil cadmium were 0, 5,10,20,40 and 80 mg Cd/kg soil. Results of this study showed that application of biological fertilizers increased yield and growth indices of tomato and caused the concentrations of micronutrients to increase in aerial part and root of this plant. The highest rate of yield was generated by combination of biological fertilizers M1, so that it was significantly different from other combination, and by contrast the result of the combination of biological fertilizers M3 was not significantly different from the control. But the yield and growth indices of tomato plant decreased as the levels of soil cadmium increased. The level of 80 mg Cd/kg soil decreased tomato yield compared with control by 67%.