为了探讨不同初始浓度石油污染土壤堆腐化修复机制，以石油降解菌剂和腐熟鸡粪为调理剂，研究了初始浓度分别为5000（T1）、10000（T2）和50000 mg/kg（T3）的石油污染土壤堆腐化修复过程石油烃类污染物降解动力学特征和微生物群落多样性。结果表明：堆腐化修复过程石油烃类污染物降解符合一级反应动力学，反应常数分别为0.012、0.094和0.050 d-1，半衰期分别为6.79、7.37和13.86 d。整个堆腐过程石油烃类污染物平均降解速率分别为112.08、230.05和887.93 mg/(kg·d)。3个处理的孔平均颜色变化率（average well color development）和碳源利用率（除芳香烃类化合物外）随堆腐进程的推进逐渐升高，在堆腐中、后期达到最大，T3处理显著高于T1、T2处理。多聚物类和糖类代谢群是堆腐体系中的优势菌群。主成分分析表明3个处理的微生物群落差异显著（除第9天外），起分异作用的碳源主要是糖类和羧酸类。微生物群落的丰富度指数和均一度指数随堆腐进程的推进逐渐升高并在堆腐后期达到最大，与T1处理相比， T3处理分别高了0.21%和17.64%，差异达到显著水平（P<0.05）。微生物群落优势度指数在中期达到最大，T1处理分别比T2、T3处理高2.12%和9.44%，3个处理间差异不显著（P>0.05）。堆肥结束时3个处理的种子发芽指数（seed germination index, SGI）分别比堆腐初期提高了18.26%、20.42%和36.41%。该研究结果为黄土高原不同程度石油污染土壤堆腐化修复的应用提供参考依据和理论基础。%In order to investigate the mechanism of bioremediation of petroleum hydrocarbon-contaminated soil by composting, an experiment was conducted with bacteria agent and mature chicken manure as amendment. We studied the kinetics of petroleum hydrocarbon degradation and the diversity of microbial community during the bioremediation of petroleum hydrocarbon-contaminated soil by composting with different concentrations. The concentrations included 5 000 mg/kg (T1), 10 000 mg/kg (T2) and 50 000 mg/kg (T3). The results showed that biodegradation of petroleum hydrocarbon followed the first-order model during composting. The constants of biodegradation rate in 3 treatments respectively were 0.012, 0.094and 0.050/d. The half-life period was 6.79 d in T1 treatment, 7.37 d in T2 treatment and 13.86 d in T3 treatment. The average degradation rate was 112.08 mg/(kg·d) in T1 treatment, 230.05 mg/(kg·d) in T2 treatment and 887.93 mg/(kg·d) in T3 treatment during composting. This indicated that the average degradation rate increased with the increase in the petroleum hydrocarbon concentration. The average well-color development (AWCD) and use of carbon sources (except aromatic compounds) increased during the composting process, and reached the peak at the end of composting. There was a sharp rise in AWCD at the beginning of composting. This phenomenon could be easily explained by the fact that the total activity of soil microbial community increased significantly in the early of the process, while the use of carbon sources rose. The value of AWCD and the use of carbon sources in T3 were significantly higher than that in T2 and T3 at the end of composting. This demonstrated that there were dominant microbial consortia in the treatment with higher petroleum hydrocarbon concentration, and the dominant microbial consortia raised the total activity of soil microbial community and the use of carbon source. The dominant microbial consortia were metabolism communities of polymers and carbohydrates in composting process. The principal component analysis results revealed that there was a significant difference in soil microbial community structure among 3 treatments and the difference was mostly related to the use of carbohydrates and carboxylic acids. The microbial community diversity, as indicated by Shannon and McIntosh, increased during the composting process, and reached the peak at the end of stage. The values of Shannon and McIntosh in T3 were 0.21% and 17.64% higher than those in T1 respectively, and the differences were significant at 0.05 level (P<0.05). Simpson reached the maximum in middle stage. The value of Simpson in T1 was 2.12% and 9.44% higher than that in T2 and T3 respectively (P>0.05). This phenomenon was likely due to the stimulating effect of lower concentration of petroleum hydrocarbon on the growth of the dominant microbial consortia. However, the structure of soil microbial community in 3 treatments had no significant difference. The seed germination index (SGI) reached the maximum at the end of composting. Compared with the first stage of composting, the SGI in 3 treatments increased respectively by 18.26%, 20.42% and 36.41%. This suggested that bioremediation of petroleum hydrocarbon-contaminated soil by composting had a high effect for improving soil health. The results can provide a reference and theoretical basis for the application of bioremediation in petroleum hydrocarbon-contaminated soil in the Loess Plateau by composting with different concentrations.
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