Earthworms and sp. are known for their strong organic compound decomposition ability and wide distribution in soil. However, interactions of soil organic matter decomposition with soil properties and whether microbial species such as sp. could assist earthworms in carbon and nitrogen transformation in soil remain poorly understood. Earthworms (, ) and sp. were introduced in non-contaminated and cadmium-contaminated soils under controlled laboratory conditions for 20 days. We examined their individual or combined effects on carbon and nitrogen forms and related enzyme activities to assess their influence on soil C and N cycling. Individual sp. inoculation led to significantly decreased organic carbon (SOC) contents, reducing it by 16.5% in non-contaminated soil and by 3.77%, in Cd-contaminated soil. It resulted in an increased microbial biomass carbon (MBC) contents, reaching 1685 ± 292 mg·kg in non-contaminated soil. Individual introductions of and caused a decline in SOC content in non-contaminated soil, but increased significantly dissolved organic carbon (DOC) and alkali-hydrolysable nitrogen (AN) contents by 75.8%, 53.6% and 32.9%, 20.9%, respectively. In contrast, in Cd-contaminated soil, only the significant combined effects of earthworms and sp. were linked to significant increase in SOC contents, raising by 7.22% and 9.64% in sp. and sp. treatments, respectively. In non-contaminate soil, the combined effects of earthworm and sp. further increased DOC and AN content by 212%, 134% and 31.3%, 25.4% in the treatments of sp. and sp., respectively; the highest ratios of DOC to SOC and AN to total Nitrogen (TN) were found in the earthworm + sp. treatments as well. In non-contaminated soil, sp. and earthworms mainly influenced β-glucosidase (BG), urease (URE), N-acetyl-β--glucosaminidase (NAG) activities and fluorescein diacetate hydrolysis (FDA) hydrolysis, while in Cd-contaminated soil, they mainly influenced invertase (INV), NAG, URE, and protease (PRO) activities. Principal component analysis indicated that in non-contaminated soil, the earthworm activities dominated the mineralization processes of soil carbon and nitrogen, and sp. can intensify this process when it was inoculated in soil along with earthworms. Furthermore, both earthworm species increased C and N levels by elevated INV and PRO activities in combined inoculation. However, in contaminated soil, the impact of earthworm inoculation on soil C stabilization showed a species dependent pattern. reduced C mineralization by decreasing URE activities, while enhanced C stabilization by increasing INV activities and decreasing PRO activities. In conclusion, earthworms played a key role in enhancing C and N mineralization in non-contaminated soil and promoting C stabilization in contaminated soil. Both earthworm species followed similar strategies in the former process but adopted different strategies in the latter. When introduced individually, sp. was able to promote mineralization in both soils, primarily assisting earthworms in improving carbon and nitrogen mineralization in non-contaminated soil but hindering these processes in Cd-contaminated soil. These findings provide insights into the combined effects of earthworms and microorganisms on carbon and nitrogen cycling.

中文翻译：

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蚯蚓和鞘氨醇杆菌的单独和联合作用。非污染和镉污染土壤中土壤有机碳、氮形态和酶活性的影响

蚯蚓和 sp。以其较强的有机化合物分解能力和在土壤中分布广泛而闻名。然而，土壤有机质分解与土壤性质的相互作用以及微生物物种（例如 sp）是否存在相互作用。能否帮助蚯蚓进行土壤中的碳和氮转化仍然知之甚少。蚯蚓 (, ) 和 sp. 在受控实验室条件下将其引入未污染和镉污染的土壤中 20 天。我们检查了它们对碳和氮形式以及相关酶活性的单独或组合影响，以评估它们对土壤碳和氮循环的影响。个体sp。接种后显着降低了有机碳（SOC）含量，未污染土壤中有机碳含量降低了16.5%，镉污染土壤中有机碳含量降低了3.77%。这导致未污染土壤中微生物生物量碳（MBC）含量增加，达到1685 ± 292 mg·kg。单独引入 和 导致未污染土壤 SOC 含量下降，但溶解性有机碳（DOC）和碱解氮（AN）含量显着增加，分别增加了 75.8%、53.6% 和 32.9%、20.9%。相比之下，在Cd污染土壤中，只有蚯蚓和sp的联合效应才显着。与 SOC 含量显着增加有关，sp 分别增加了 7.22% 和 9.64%。和sp。分别进行治疗。在无污染的土壤中，蚯蚓和sp的综合作用。sp处理中DOC和AN含量进一步增加212%、134%和31.3%、25.4%。和 sp.，分别；在蚯蚓 + sp 中发现 DOC 与 SOC 以及 AN 与总氮 (TN) 的比例最高。治疗也是如此。在未受污染的土壤中，sp。蚯蚓主要影响β-葡萄糖苷酶(BG)、脲酶(URE)、N-乙酰基-β-氨基葡萄糖苷酶(NAG)活性和荧光素二乙酸酯水解(FDA)水解,而在Cd污染土壤中主要影响转化酶(INV) )、NAG、URE 和蛋白酶 (PRO) 活性。主成分分析表明，在未受污染的土壤中，蚯蚓活动主导了土壤碳、氮和蠕虫的矿化过程。当它与蚯蚓一起接种在土壤中时，可以强化这一过程。此外，两种蚯蚓都通过联合接种中 INV 和 PRO 活性的提高而增加了 C 和 N 水平。然而，在污染土壤中，接种蚯蚓对土壤碳稳定的影响表现出物种依赖性模式。通过降低 URE 活性来减少碳矿化，同时通过增加 INV 活性和减少 PRO 活性来增强碳稳定性。总之，蚯蚓在增强非污染土壤中碳、氮矿化和促进污染土壤中碳稳定方面发挥了关键作用。两种蚯蚓在前一过程中遵循相似的策略，但在后一过程中采取不同的策略。当单独引入时，sp。能够促进两种土壤的矿化，主要是帮助蚯蚓改善未污染土壤中的碳和氮矿化，但阻碍了镉污染土壤中的这些过程。这些发现为了解蚯蚓和微生物对碳和氮循环的综合影响提供了见解。