3.1 Soil physicochemical properties
The physical and chemical properties of soil with different oil pollution duration showed significant differences (Fig. 1 ). The results showed that compared with the control, the contents of TPH, TC, TN, TS, and TP in soil were increased by oil pollution (one-way ANOVA, p <0.05), and the soil pH was significantly reduced. For soil electric conductivity, short-term contaminated soil is significantly lower than long-term oil-contaminated soil. In addition, the soil scanning electron microscope photos show that (Fig. S2 ) after the soil is polluted by oil, the soil is more likely to form a large block structure. At the same time, the uncontaminated soil is not only looser but also has a porous surface.