Integral phytotoxicity of oil-contaminated chernozem after remediation with biochar and bacterial preparation

Abstract

Relevance. Soil pollution with oil has a significant impact on soil fertility and productivity when growing crops. During soil remediation, insufficient attention is paid to soil phytotoxicity assessment in terms of the intensity of the initial growth and development of plants. The results of the study of ordinary chernozem phytotoxicity evaluation on the example of winter barley (Hordeum vulgare L.) after remediation with biochar and a bacterial preparation, containing strains of Bacillus & Paenibacillus, are presented. Aim. To evaluate ordinary chernozem integral phytotoxicity after remediation with biochar and a bacterial preparation, containing strains of Bacillus and Paenibacillus. Objects. Ordinary heavy loamy chernozem, under model conditions, which 5% of the soil mass are oil-contaminated. For soil remediation from oil pollution, biochar and a bacterial preparation with Bacillus & Paenibacillus strains were applied in various combinations: independent application of ameliorants, joint application, inoculation of bacterial preparation with Bacillus & Paenibacillus on biochar. The period of soil incubation with biochar and of bacterial preparation with Bacillus & Paenibacillus has a duration of 30 days. Methods. The residual oil content was determined by the method of extraction with carbon tetrachloride with detection on an infrared analyzer. Soil phytotoxicity after remediation was assessed by indicators of the intensity of initial growth and development of winter barley (Hordeum vulgare L.): germination, germination rate, germination energy, germination friendliness, shoot length, root length, shoot phytomass, root phytomass. As a result of determining these indicators, a complex integral indicator of soil phytotoxicity (IIPht) was calculated. Results. The combined use of biochar with of bacterial preparation with Bacillus & Paenibacillus in oil-contaminated soil leads to the most effective reduction in oil content than when self-introduced and inoculated with of bacterial preparation with Bacillus & Paenibacillus on biochar at the recommended and 100-fold dose, the efficiency is 33 and 58%, respectively. Based on the analysis of phytotoxicity, the highest sensitivity of indicators of barley initial growth intensity was established: germination, friendliness and germination rate. With the independent application of biochar and of bacterial preparation with Bacillus & Paenibacillus, the most informative indicators are shoot phytomass, germination and germination rate; with the combined application of biochar and of bacterial preparation with Bacillus & Paenibacillus, germination energy, shoot length and shoot phytomass; with inoculation of of bacterial preparation with Bacillus & Paenibacillus on a biochar, root length, phytomass of shoots and roots. The study of the phytotoxicity of oil-contaminated Haplic Chernozem after remediation made it possible to establish the ecological efficiency and expediency of using only biochar and biochar inoculated with of bacterial preparation with Bacillus & Paenibacillus.