Study the interactional effect between various concentrations of (Fe) and (Sinorhizobium Meliloti) on growth, and nitrogen fixation process in Alfafa (Medicago Sativa) Plants

This experiment studied the effect of various concentrations of Fe-chealate (Fe) in the efficacy of four isolates of Sinorhizobium melioti, isolated locally from root nodules of alfafa plants (Medico sativa), in nitrogen fixation process these plants gathering from different locations in Iraq (Baghdad). The rhizobiume isolates were named (R1, R2, R3, and R4).
This study divided in two parts, a laboratory experiment measured the colony forming unit (CFU) for all isolated strains under 3 concentrations of (Fe) (2mg, 4mg, 8mg)/ L, through incubation of 48, 72 hours, In 28c° The results of this experiment showed a significant increasing in a count of (CFU) (P ≤ 0.05) for all strains, specially under the concentrations (4mg, 8mg,) Fe/L.
The farmer experiment alfafa plants were agriculture in plastic pots size (5kg) soil putted in the green house, then studied some growth parameters of alfafa plants such as: the length of shoot, dry weight, numbers of root nodules, and the concentration of nitrogen and protein in plants. The results showed that the of adding concentrations of (0.2mg , 0.4mg , 0.6mg) (Fe) / L to the soil with bacterial isolates was very effective in the efficiency of all four Sinorhizobium isolates under study, in nitrogen fixation process, and increasing their ability for fixing nitrogen when association with Medico sativa plants. The results present a significant increasing in the growth parameters were mentioned.
These parameters were increased when increased the (Fe) concentrations. The treatment (bacteria & 0.6mg Fe) showed the best results comparing with other treatments isolates. The isolates R3 present the best results comparing with other isolate but R2 strain showed the less significant results in this study.