The Effectiveness of Different Forms of Nitrogen Fertilizers in Phytoremediation on Oil-Contaminated Typical Chernozem

Abstract

The study is devoted to the role of optimized nutrition and the development of a mixture of grasses in high-polluted oil-contaminated typical chernozem. The influence of different forms of nitrogen fertilizers at a moderate level of plant nitrogen supply in the presence of oil pollution has been investigated using indicators of soil agrochemical and enzymatic properties, as well as the productivity and qualitative composition of the plants used for phytoremediation. Oil soil contamination at doses of 5 and 7 g of oil per 1 g of soil significantly negatively affects the productivity rates of the used plants and leads to a reduction of their biomass and a decrease in the content of major mineral elements (NPK). The nutrition optimization by application of mineral fertilizers leads to an increase in biomass and improves the qualitative composition of plants growing under oil pollution conditions. The most favorable conditions for the growth and development of plants are associated with application of nitrate forms of nitrogen fertilizers, but not ammonium or ammonium–nitrate forms in equivalent doses. Activity rates of the studied enzymes (catalase, urease, and phosphatase) highly depend on the oil content in the soil. Application of mineral fertilizers leads to an increase of the enzymatic activity of typical chernozem proportionally to a decrease in oil content in the soil. This indicates intensification of oil hydrocarbon degradation processes associated with application of mineral fertilizers.