The role of organic amendments for natural degradation of aged persistent organic pollutants (POPs) in agricultural soils remains controversial. We hypothesised that organic amendments enhance bacterial activity and function at the community level, facilitating the degradation of aged POPs. An incubation study was conducted in a closed chamber over 12 months to assess the effects of selected organic amendments on extractable residues of aged dieldrin. The role of bacterial diversity and changes in community function was explored through sequenced marker genes. Linear mixed effect models indicated that, independent of amendment type, cumulative CO₂ release was negatively associated with decreases in dieldrin concentration, by up to 7% per µmol CO₂–C respired by microorganisms. The addition of poultry litter led to the highest daily carbon mineralisation, which was associated with low dieldrin dissipation after 9 months. In comparison, biochar resulted in significant decreases in extractable dieldrin residues over time, which coincided with shifts towards aerobic, oligotrophic, gram-negative bacteria, some with dehalogenation metabolism, and with increased potentials for biosynthesis of membrane components such as fatty acids and high redox quinones. The results supported an alternative theory that labile carbon promoted blooms of copiotrophic growth, which suppressed the required community-level traits and oligotrophic diversity to degrade chlorinated pollutants.

有机改良剂对农业土壤中老化的持久性有机污染物 (POPs) 自然降解的作用仍然存在争议。我们假设有机改良剂增强了社区层面的细菌活性和功能，促进了老化 POPs 的降解。在密闭室中进行了为期 12 个月的孵化研究，以评估选定的有机改良剂对陈年狄氏剂可萃取残留物的影响。通过测序标记基因探索了细菌多样性和群落功能变化的作用。线性混合效应模型表明，与修正类型无关，累积 CO ₂释放与狄氏剂浓度降低呈负相关，每 µmol CO _{2最多降低 7%}-C 由微生物呼吸。家禽垫料的添加导致每日碳矿化最高，这与 9 个月后狄氏剂消散率低有关。相比之下，随着时间的推移，生物炭导致可提取的狄氏剂残留量显着减少，这与向需氧、贫营养、革兰氏阴性细菌的转变相吻合，其中一些具有脱卤代谢，并且膜成分（如脂肪酸和高氧化还原）的生物合成潜力增加醌类。结果支持了另一种理论，即不稳定的碳促进了富养生长的大量繁殖，从而抑制了降解氯化污染物所需的群落水平特征和贫养多样性。