Influence of k- solubilizing fungi on potassium release from silicate minerals and some growth indexes on Corn (Zea mays L.)

Use of Silicate minerals and potassium solubilizing microorganisms are methods of potassium supplying to plants. Present study with the aim of isolation of potassium solubilizing fungi from rhizosphere soil and evaluation of quantitative ability of released potassium from different sources of silicate by strains, was carried out as factorial experiment based on completely randomized design with three replications. Laboratory factors were including potassium sources in four levels (Biotite, Phlogopite, Illite and Muscovite), incubation time in six levels (0, 1, 3, 5, 7 and 10) and microorganisms in four strains (A. niger, A. terreus, Trichoderma harzianum and Penicellium sp) and greenhouse factors were including potassium sources in five levels (control, soluble potassium, Phlogopite, Illite and Muscovite) and microbial inoculation in two levels (non-inoculated control and inoculation with fungi). The results showed that the highest potassium content (3. 21 µg/ml) was released after ten days incubation from biotite by strains of KSB2 that was not significantly different from other fungal strains. The microbial inoculation increased 25. 47 and 30. 37 percent plant high and root dry weight compared to control treatments, respectively. The use of silicate minerals and microbial inoculation have a significant effect on some growth indices (stem diameter and shoot dry weight) and the content of potassium. The microbial inoculation increased potassium content of shoot and root in illite 3. 37 and 1. 43 times higher than control treatment, respectively. In general, the use of fungal inoculum have significant effect on potassium release of silicate minerals and plant growth.