The choice of indicators for the ecological rationing of petroleum products in chestnut soils

Abstract

Th e response of the microbial community of soils to diff erent levels of oil contamination in a model experiment was studied according to indicators: basal respiration (BR), basal induced respiration (SIR), carbon of microbial biomass (Cmic), potential denitrifi cation (DNF), methanogenesis, catalase activity. Th e soils are represented by light chestnut (Haplic Kastanozems Sodic) and meadow-chestnut (Gleyic Kastanozems Chromic) dry-steppe zone of the Stavropol area, diff ering in the organic matter content, salinity and the content of physical clay. Th e intensity of BR increased aft er 30 days of the crude oil input into the soils and caused the growth of Cmic due to the activation of oil-oxidizing microorganisms in anaerobic zones of soils. DNF varied in light chestnut and meadow-chestnut soils not directly, that was probably due to the level of organic matter content in soils and their salinity. Catalase activity was a sensitive indicator for the petroleum hydrocarbons in light chestnut soil, but salinity was the determining factor in its activity in meadow chestnut soil. Biotesting with the use of worms Eisenia fetida showed the inability of test organisms to survive in non-contaminated chestnut soils. A signifi cant indicator that did not depend on natural factors in chestnut soils was BR and related indicators. Catalase activity and DNF have limitations on the salinity factor.