Impact of oil contamination of grey forest soil on its nutrient status and plant safety

The study was carried out in the Republic of Tatarstan (Volga Federal District of the Russian Federation) in grey forest middle loamy soil with weak acid reaction of the medium, low humus content, increased content of labile forms of phosphorus and potassium. The soil was deliberately contaminated with oil at a dose of 25 l/m2. There is close positive linear relationship (R2=0.845) between the amount of bens(a)pyrene (BP) and petroleum substances in soil. The BP content in oil-contaminated horizons (0–15, 15–30, 30–45 cm) of soil exceeded the maximum allowable concentration by 10.5–19.5 times that demonstrates a serious threat to vegetable products growing on oil-contaminated lands. Due to oil contamination, the content of most labile forms of nutrients (N, P, K, B, Mo, Zn) decreased and others remained unchanged (Cu, Co) or increased (Mn). At the same time, these changes were not so significant, because the groups of soil supply with labile forms of nutrients, except phosphorus and potassium, did not change under the influence of oil