Iron and Potassium Release from Muscovite and Vermiculite by Some Plant Growth Promoting Bacteria

Potassium and iron as essential plant nutrients play important role in growth and development of plants. However, in most agricultural areas of the world, deficiency of available iron in the soil is prevalent and it is expected to be intensified by increasing the lime content in soil, while insufficiency of available potassium in the soil occurs due to fixation, runoff, leaching, and erosion. Potassium solubilizing bacteria have the capacity to dissolve potassium from insoluble K minerals. This research was carried out to dissolve iron and potassium from insoluble minerals by rhizospheric bacteria. The experiment was done as factorial with completely randomized design. Treatments included minerals (muscovite and vermiculite) and four strains of potassium releasing bacteria including Enterobacter cloacae (R33 and E1 strains) and Pseudomonas putida (R9 and E49 strains) and the control (without inoculation) during three time periods (7, 14 and 28 days). Aleksandrov broth medium containing 2 grams of each mineral was used in order to study iron and potassium release. The results showed significant (p