Elrys Ahmed S, Wen YuHong, Feng Di, El-Mekkawy Rasha M, Kong Mengru, Qin Xiaofeng, Lu Qiqian, Dan Xiaoqian, Zhu Qilin, Tang Shuirong, Wu Yanzheng, Meng Lei, Zhang Jinbo
College of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China; Soil Science Department, Faculty of Agriculture, Zagazig University, Zagazig 44511, Egypt.
College of Tropical Agriculture and Forestry, Hainan University, Haikou 570228, China.
J Hazard Mater. 2025 Jun 5;489:137524. doi: 10.1016/j.jhazmat.2025.137524. Epub 2025 Feb 7.
Microbial mediated carbon and nitrogen cycling response to cadmium are often observed in soil; however, a unified framework of this response has not yet been established. By analyzing 1232 observations from 166 publications, we found that cadmium decreased microbial biomass carbon (-16 %) and nitrogen (-21 %), dissolved organic nitrogen (-27 %), nitrification rate (-17 %), microbial respiration rate (-12 %), and β-1,4-glucosidase (-21 %) and urease (-16 %) activities, but increased microbial metabolic quotient (+11 %) and fungal-to-bacterial ratio (+39 %). The cadmium impact was concentration-dependent, becoming more pronounced at higher concentrations. Increasing cadmium concentration reduced soil N mineralization rate and total N content, but increased microbial biomass carbon-to-nitrogen ratio. These results indicate that cadmium reduced carbon and nitrogen assimilation into microbial biomass and limited soil inorganic nitrogen production. Soil bulk density drove soil microbial biomass and nitrogen availability response to cadmium. Lower soil bulk density and higher initial carbon and clay contents and soil pH reduced the negative impact of cadmium on microbial biomass and nitrogen availability, suggesting that anthropogenic activities that enhance soil quality may mitigate the inhibitory effect of cadmium on soil carbon and nitrogen cycling. Our analysis provides critical implications for improving our understanding of the ecological consequences of cadmium on soil carbon and nitrogen cycling.
土壤中经常观察到微生物介导的碳氮循环对镉的响应；然而，尚未建立这种响应的统一框架。通过分析来自166篇出版物的1232条观测数据，我们发现镉降低了微生物生物量碳（-16%）和氮（-21%）、溶解有机氮（-27%）、硝化速率（-17%）、微生物呼吸速率（-12%）以及β-1,4-葡萄糖苷酶（-21%）和脲酶（-16%）的活性，但提高了微生物代谢商（+11%）和真菌与细菌的比例（+39%）。镉的影响具有浓度依赖性，在较高浓度时更为明显。镉浓度的增加降低了土壤氮矿化速率和总氮含量，但提高了微生物生物量碳氮比。这些结果表明，镉减少了碳和氮向微生物生物量的同化，并限制了土壤无机氮的产生。土壤容重驱动了土壤微生物生物量和氮有效性对镉的响应。较低的土壤容重、较高的初始碳和粘土含量以及土壤pH值降低了镉对微生物生物量和氮有效性的负面影响，这表明提高土壤质量的人为活动可能减轻镉对土壤碳氮循环的抑制作用。我们的分析为增进我们对镉对土壤碳氮循环的生态后果的理解提供了关键启示。
