en Environmental Health, Sciences, and Engineering Environmental Health, Sciences, and Engineering پژوهشي Original Article <div><span style="font-size:14px;"><span style="font-family:Times New Roman;"><span style="line-height:150%"><b><span style="background:white"><span style="line-height:150%"><span style="color:#1d2228">Background</span></span></span></b>: <span style="line-height:150%">This research investigated the effects of various iron fertilizers and the introduction of <i>Piriformospora indica</i> (<i>P. indica</i>) fungus on the biodegradation of diesel oil in soil experiencing water deficiency.&nbsp;&nbsp; </span></span><br> <span style="line-height:150%"><b><span style="background:white"><span style="line-height:150%"><span style="color:black">Methods</span></span></span><span style="line-height:150%">:</span></b> <span style="line-height:150%">The treatments included applying pure Fe at rates of 0, 60, and 90 kg/ha, derived from Fe sulfate (FeSO</span>_{<span style="line-height:150%">4</span>}<span style="line-height:150%">) and Fe slag (containing 58.2 % Fe</span>_{<span style="line-height:150%">2</span>}<span style="line-height:150%">O</span>_{<span style="line-height:150%">3</span>}<span style="line-height:150%">), in a diesel oil-contaminated soil with concentrations of 0 % and 8 % (W/W). These treatments were implemented in a corn plant cultivation system, where the plants were inoculated with <i>P.indica</i> fungus under conditions of drought stress. After 90 days, the plant and soil Fe concentration was determined by atomic absorption spectroscopy (AAS). Furthermore, the extent of diesel oil bio-degradation in the soil was assessed.</span><span style="line-height:150%"></span></span><br> <span style="line-height:150%"><b><span style="line-height:150%">Results: </span></b><span style="line-height:150%">Applying 90 kg/ha pure Fe from Fe sulfate and Fe slag significantly enhanced the bio-degradation of diesel oil in the soil by 13.2 and 16.1 %, respectively. However, the efficiency of this process was lower under drought-stress conditions. In addition, Plant inoculation with <i>P.indica</i> significantly enhanced the diesel oil bio-degradation of the soil contaminated with 8 % (W/W) diesel oil under drought stress by 15.7 %. Moreover, the soil microbial activity was significantly increased by 14.1 %.&nbsp;&nbsp; </span></span><br> <span style="line-height:150%"><b><span style="line-height:150%">Conclusion: </span></b><span style="line-height:150%">The combined use of<b> </b><i>P.indica</i>, along with iron slag and iron sulfate, markedly enhances the biodegradation process of diesel oil within the soil.</span></span></span></span></div> Iron slag, Bio-degradation, Diesel oil, Corn, Piriformospora indica Fungus, 111 117 http://jhehp.zums.ac.ir/browse.php?a_code=A-10-230-12&slc_lang=en&sid=1 Amir Hossein Baghaie ambaghaie@yahoo.com 100319475328460015771 100319475328460015771 Yes Department of Soil Science, Arak Branch, Islamic Azad University, Arak, Iran. Amir Ghaffar Jabbari amir@yahoo.com 100319475328460015772 100319475328460015772 No Departments of Biology, Arak Branch, Islamic Azad University, Arak, Iran. Maedeh Nazmabadi nazmabadimaedeh@gmail.com 100319475328460015773 100319475328460015773 No Departments of Biology, Arak Branch, Islamic Azad University, Arak, Iran.