The Effect of Plant Growth Promoting Rhizobactria (PGPR) on Interaction with Biochar and Compost of Trees Pruning on Bioavailability of Some Micronutrients in the Wheat Rhizosphere (Triticum aestivum L.)

In arid and semiarid regions of Iran, most of soils are calcareous and low in organic matter, therefore are deficient in micronutrients. This research was aimed to evaluate the bioavailability of selected micronutrients as affected by biochar and compost of trees pruning in the presence of PGPR in wheat rhizosphere. In a rhizobox study, an experiment carried out in a completely randomized design under greenhouse conditions. The factors including the organic sourses (pruning waste biochar, pruning waste compost and control), microbial inoculation (with and without PGPR). At the end of the growth period, organic matter (OM) cotent and bioavailability of micronutrients including iron (Fe), zinc (Zn), copper (Cu) and manganese (Mn) in the rhizosphere soil and their uptake by wheat plant were determined. The results indicated that OM, Fe, Zn, Mn and Cu were significantly increased in rhizosphere soil under the influence of organic sources and PGPR inoculation. Addition of biochar under inoculation conditions resulted in 84.6% and 17.9% increase in rhizosphere Fe and Mn, respectively, compared to the non-inoculated treatment. The presence of PGPR increased the bioavailability of Zn and Cu by 52.2% and 34.9%, respectively, in compost treatment compared to the non-inoculated ones. Application of organic sources and bacterial inoculation increased the micronutrient uptake by plant.