Yield and Chemical Composition of Spring Wheat Harvest on Oil-contaminated Grey Forest Soil

The study was carried out in the Republic of Tatarstan (Povolzhsky Federal District of the Russian Federation) in the conditions of grey forest medium loamy soil with weakly acidic reaction of the environment, low humus content, increased and average content of mobile forms of phosphorus and potassium respectively. The soil was intentionally polluted with oil at the rate of 10, 20 and 40 l/m2. Close negative correlation of spring wheat yield from oil dose (R2=0,945...0,997) and positive dependence on the statute of limitations of single soil contamination (R2=0,713...0,993) was established. The possibility of gradual, though slow, natural elimination of phytotoxicity of oil-contaminated grey forest soil without special methods of recultivation is noted. The content of nitrogen, phosphorus and potassium in spring wheat plants under the influence of oil pollution has not changed significantly, but accumulation of carcinogenic substances in them was found. It is indicated that for the objective assessment of detoxification of oil-contaminated soils it is necessary to take into account not only the productivity of plants, but also to study in depth the chemical composition of the crop