Effect of some Bacterial Isolates on Supplying Potassium to Maize

There are large amount of K in soil but main of that are not in the available form for plants hence potassium deficiency can occur in this condition. Hence, dissolution of soil minerals with microorganisms is notable and it could be very important to use potassium releasing bacteria for supplying potassium to plants. Accordingly, this experiment was performed in order to determine the effect of different bacterial isolates on providing potassium in corn. This greenhouse experiment was performed using completely randomized design with 3 replications and with application of disinfected seeds of corn (single-cross 704). Experiment treatments were including 10 treatments with different bacterial isolates inoculation (including Pseudomonas, Bacillus, Enterobacter and Azotobacter), fertilizer treatments (K50 and K100; using 50% and 100% of K2SO4 based on fertilizer recommendation) and negative control (no bacterial inoculation and no fertilizer). The experiment prolonged to the beginning of reproductive phase and after harvesting and oven- drying of plant specimen, dry weight of shoot and root were weighed. Eventually, plant samples were digested and concentration of potassium, phosphorus and nitrogen were measured in extracts. In addition the amount of elements uptake or content was calculated. Results showed expect root dry weight, phosphorus transfer factor and shoot phosphorus concentration, all the parameters were significantly affected by treatments. The highest total potassium content were obtained in Pseudomonas sp. Az-8 and 100% fertilizer recommendation, respectively equal to 1582 and 1570 mg/plant. Among bacterial isolates, the highest total content of phosphorus and nitrogen belonged to Az-8 that was equal to 50.59 and 264.5 mg/plant, respectively. But the highest shoot potassium concentration and content were in 100% fertilizer treatment, 2.55% and 1077.289 mg per shoot weight, respectively. But in regard to bacterial isolates, this parameter was measured in A. chroococcum 14SP2-1 with an increasing of 24% and 16% as compared with control. The highest root potassium concentration and content (2.4% and 605.1 mg per root weight, respectively) were observed in Pseudomonas Az-8. This isolate has the highest efficiency of potassium nutrition by 104.5%. The maximum shoot dry weight was observed in 50% and 100% fertilizer treatments (44.42 and 44.06 g). In general results of experiment showed, some bacterial inoculations were better than chemical fertilizers in some parameters and it could be related to biological effects of bacteria in soil. Overall, it could be suggested to use selected bacteria such as Pseudomonas Az-8, A. chroococcum 14SP2-1 and Enterobacter S16-3 for ongoing and future experiments.