Influence of diesel and biodiesel fuel-contaminated soil on microorganisms, growth and development of plants

The paper presents the results of studies concerning the phytotoxicity of biodiesel and its diesel oil blends with a germination and root elongation test. The paper also analyses the effect of fuel on the number and activity of soil microorganisms and the reaction of plants used in the research. Fuel was introduced into the soil at a concentration of 10 and 50 g/kg dry mass soil. Based on the test results, it was found that from among 19 plants species representing 5 families taxonomically, only 4 species showed resistance to the presence of the fuel in soil, regardless of their type and dose (Glycine max (L.) Merill, Helianthus annuus L., Lupinus luteus L., cv. Lord and Pisum sativum L., cv. Eureka). Fuel generally reduced the number of heterotrophic microorganisms, and stimulated the growth of decomposing microorganisms and content of biomass. Significant differences in the number and activity of microorganisms were associated with the presence of biodiesel in the soil. The fuel had a negative influence on the biometric and physiological parameters of plants. A shorter length of shoots and roots was noted, especially in objects with biodiesel, reduced water content, and general content of assimilation pigments.