Total petroleum hydrocarbon degradation in contaminated soil as affected by plants growth and biochar

This study was conducted to investigate the effect of barley and oat plants and poultry manure biochar on total petroleum hydrocarbons (TPHs) degradation and microbial respiration at 4, 6 and 8% TPH levels in soil. Results showed that with increasing TPH levels, plants growth and TPHs degradation significantly reduced; however, the presence of plants in contaminated soil and application of biochar significantly increased degradation of TPHs and microbial respiration rate. TPHs reduction percentage in soils cultivated with barley and oat were about 1.02 and 0.75 times higher than unplanted soil. Microbial respiration rate in soil cultivated with barley and oat increased about 67 and 34.5% compared to unplanted treatment. TPHs reduction percentage and average of microbial respiration rate in biochar-treated soil significantly increased by 21.76 and 37.73% for barley and 20.36 and 45.18% for oat plant compared to non-biochar treatments, respectively. Barley and oat appear to be suitable for degradation of TPHs, and biochar is useful amendment for enhancing TPHs degradation in this soil.