**3. Degradation of oil hydrocarbons by soil microbiota and laboratory bacteria introduced into soil**

## **3.1 Soil samples**

Arable soil samples from the Krasnodar region of Russia were used in the experiment after they had been cultivated with corn (С4-plant). Soil samples were sieved through a 2 mm sieve and then moistened to 60 % of field capacity. The initial organic matter content was about 4.9 % of dry soil (DS) weight or 19.6 mg С g-1 DS. The carbon isotope composition in the initial SOM was characterized by a 13C value of -23.01 0.2 ‰, typical of soils vegetated by С4-plants.
