华中农业大学揭示增温促进稻田土壤有机质矿化的潜在机制

　　The o ngoing global warming is causing paddy soil to come under threat by hitherto unseen levels of carbon and nitrogen loss. The mechanism of soil organic matter （SOM� compo nents and microbial me tabolism respo nding to increased temperature is complicated; for example, the temperature sensitivity （Q10� of SOM decomposition in rice topsoil and subsoil remains poorly understood. In this study, 0�C30 cm columns of undisturbed paddy soil were collected and incubated at 5, 15, or 25 � for 117 days to investigate the effect of temperature on SOM decomposition and microbial characteristics in different soil layers. Results showed that Q10 of subsoil �?5�C30 cm� was more than twice that of topsoil �?�C15 cm）， indicating that SOM mineralisation in subsoil was facilitated more by temperature than that in topsoil. Warming promoted the decomposition of recalcitrant SOM and reduced the fluorescent intensity of dissolved organic matter. Increased temperature exerted no significant effect on microbial biomass, but it did enhance the relative abundance of oligotrophic bacteria and promote anabolism. Therefore, recalcitrant SOM decomposition driven by oligotrophic bacteria was more sensitive to warming than labile organic matter co nsumption mediated by copiotrophic bacteria. Our findings revealed the underlying mechanisms by which elevating temperature promoted SOM mineralisation, thereby emphasising the need to remain vigilant regarding the threat to carbon dynamics in deep soil poised by global climate changes.

　　论文链接：https://doi.org/10.1016/j.soilbio.2023.109156

　　审核人：胡荣桁�/div>