Studying Behavior of Runoff Generation in a Gasoil Contaminated Soils due to Inoculation of Soil Microorganism

Runoff is one of the most important hydrological processes in ecosystems, which is very important in the management of water and soil resources. Although the use of soil microorganisms as soil inoculants in the bioengineering management of runoff has been confirmed, the use of soil microorganisms to control runoff in soils contaminated with petroleum has not been considered. Therefore, in order to evaluate inoculation of soil Bacteria, Cyanobacteria and fungi in reducing runoff in soil contaminated with petroleum, the present study was carried at plots of 0.5×0.5 m with slope of some 25% and level of 20000 mg kg-1 of gasoil and control contamination in three replicates. The plots will be then subjected to rainfall intensity of some 35 mm h−1 and duration of 30 min installed at the Rainfall Simulation Laboratory of Tarbiat Modares University at Faculty of Natural Resources. The results showed that the inoculation treatments, although there was no significant difference compared to the control treatment (P>0.05) except for the start of runoff (P<0.05), improved the components of runoff. The comparison of the mean of the study variables showed that the bacteria, cyanobacteria, fungi, bacteria+fungi, bacteria+cyanobacteria, cyanobacteria+fungi, and bacteria+cyanobacteria+fungi caused +47.10, -0.08, -10.72, -24.86, +14.85, +49.88 and +27.88 percent changes in runoff start time, +4.58, -54.04, +65.19, +72.20, -41.36, -84. 53 and +40.15 percent changes in runoff volume, and +4.75, +54.06 and -65.15, +72.28, -41.39 and -84.55 and +40.20 percent changes in runoff coefficient, respectively. The results of the research indicated the relative synergistic performance of the combination treatment of cyanobacteria + fungi in reducing the effect of gasoil on runoff properties. Finally, the results of the present study showed that the inoculation of native soil bacteria, cyanobacteria, and fungi can be an efficient and sustainable biological technology to improve runoff characteristics in areas contaminated with petroleum.