This study investigated the impact of wheat straw biochars pyrolyzed at temperatures of 100-700 ℃ (BC100-BC700) on biodegradation of phenanthrene in soils. During a 42-day experiment, biochar amendment reduced the biodegradation ratio of phenanthrene in soils by no change-77.0%. The biodegradation ratio decreased with the increase of pyrolysis temperature from 100 to 400 ℃ and then increased with the increase of pyrolysis temperature from 400 to 700 ℃, exhibiting a U-shape. Meanwhile, desorbing fraction of phenanthrene extracted by n-butanol declined with increasing pyrolysis temperature. Biochar-derived dissolved organic carbon (DOC) obviously influenced the soil DOC contents which were negatively correlated with the total relative abundances of dominant polycyclic aromatic hydrocarbon (PAH)-degraders. These results indicated that in soils amended with biochars pyrolyzed at low temperatures (i.e. 100-400 ℃), both the reduced bioavailability of phenanthrene and the reduced PAH-degrader abundance resulted in decreasing phenanthrene degradation with pyrolysis temperature. In soils amended with biochars pyrolyzed at high temperatures (i.e. 500-700 ℃; HT-biochars), two possible reasons contribute to increasing phenanthrene degradation with pyrolysis temperature: (1) high sorbed-phenanthrene concentration due to large specific surface area and high aromaticity of the biochars, and (2) the increased dominant PAH-degrader abundance for the removal of sorbed-phenanthrene due to the impact of HT-biochars on soil properties (mainly on DOC content).

本研究研究了在100-700℃（BC100-BC700）温度下热解的小麦秸秆生物炭对土壤中菲生物降解的影响。在为期42天的实验中，生物炭改良剂将土壤中菲的生物降解率降低了77.0％，未发生变化。生物降解率随热解温度从100℃升高到400℃而降低，然后随热解温度从400℃升高到700℃而增加，呈U形。同时，n萃取的菲的解吸分数丁醇随着热解温度的升高而下降。生物炭来源的溶解有机碳（DOC）明显影响土壤DOC含量，与主要多环芳烃（PAH）降解剂的总相对丰度呈负相关。这些结果表明，在低温（即100-400℃）下热解有生物炭的土壤中，菲的生物利用度降低和PAH降解物丰度降低都导致菲在热解温度下的降解降低。在高温下（即500-700℃；高温生物炭）用生物炭改性的土壤中，两个可能的原因导致热分解温度下菲的降解增加：（1）高比表面积和高芳香度导致高吸附菲浓度生物炭