Implementation of bioremediation potential of cereal and legumes in a long-term field experiment on oil-polluted sod-podzolic soil

The effectiveness of different types of grasses belonging to the Legume and Cereal families for bioremediation of oil-contaminated sod-podzolic soil has been studied. The study was conductedin a form of a long-term field experiment on the territory of the experimental field of St. Petersburg Agrarian University. The initial level of soil contamination with petroleum products, which averaged 11.5 thousand mg/kg (3.0 l/m2), was acutely toxic to plants and caused significant suppression of the aboveground biomass of grasses (up to 90–95% compared with the control). The restoration of herbaceous vegetation at the studied level of oil pollution occurred by the end of the 3rd growing season. Biodegradation of oil in the soil occurred both as a result of self-purification processes due to the activity of the native microbiota, and due to the “contribution” of plants used in biological reclamation (stimulation of rhizosphere microorganisms). Over 5 years of bioremediation of oil-contaminated sod-podzolic soil with the help of various types of grasses, the level of petroleum products decreased to 500–800 mg/ kg, i.e. by 93–95%. In the soil under all grasses related to legumes (clover, lupin, galega), the content of petroleum products in the 5th year of the experiment was significantly less than under cereals (fescue, ryegrass, KAD grass mixture). The most active was the decomposition of oil in the soil under lupin.