Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural Affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China.
Key Laboratory of Arable Land Conservation (Middle and Lower Reaches of Yangtse River), Ministry of Agriculture and Rural Affairs, College of Resources and Environment, Huazhong Agricultural University, Wuhan, 430070, China.
J Environ Manage. 2022 Jan 1;301:113916. doi: 10.1016/j.jenvman.2021.113916. Epub 2021 Oct 8.
The mineralization of soil organic matter (SOM) is closely related to the emission of greenhouse gas into atmosphere and the stability of organic carbon in soil. The influence of minerals on SOM mineralization in the specific soil received very few attentions. The influence characteristics and potential mechanisms of oxides on the mineralization of SOM in the paddy soil were observed in this study by incubating soil with the addition (dosage: 10 g kg) of prepared gibbsite, goethite, ferrihydrite or birnessite for 60 days. A sequence control treatment (753 mg CO-C kg) > goethite treatment (656 mg CO-C kg) ≈ gibbsite treatment (649 mg CO-C kg) > birnessite treatment (529 mg CO-C kg) > ferrihydrite treatment (441 mg CO-C kg ) was found in the cumulative amount of released CO in 60 days of incubation. Oxides especially ferrihydrite significantly decreased the content of dissolved organic matter (DOM) but tended to increase the content of microbial biomass carbon (MBC). The molecular structure of DOM in the paddy soil was simplified by gibbsite, ferrihydrite and birnessite after the incubation. Oxides especially birnessite and ferrihydrite reduced soil pH and the content of soil available N but increased soil redox potential (Eh). All examined oxides especially Fe oxides enhanced soil bacterial abundance but only birnessite significantly affected bacterial composition at phyla level. The stimulation on the immobilization and/or microbial assimilation of labile organic carbon, the modulation on soil basic properties (available N, pH, Eh), and the decrease of the relative abundance of some decomposing bacteria phyla such as Actinobacteria were the potential pathways of oxides in decreasing SOM mineralization.
土壤有机质（SOM）的矿化与温室气体排放到大气中和土壤有机碳的稳定性密切相关。矿物质对特定土壤中 SOM 矿化的影响受到的关注很少。本研究通过在土壤中添加（剂量：10 g kg）制备好的水铝石、针铁矿、水铁矿或锰矿，在 60 天的时间里观察了氧化物对稻田土壤中 SOM 矿化的影响特征和潜在机制。在 60 天的培养期内，释放的 CO 总量的累积量呈现出以下顺序：序列对照处理（753 mg CO-C kg）>针铁矿处理（656 mg CO-C kg）≈水铝石处理（649 mg CO-C kg）>锰矿处理（529 mg CO-C kg）>水铁矿处理（441 mg CO-C kg）。氧化物特别是水铁矿显著降低了溶解有机碳（DOM）的含量，但倾向于增加微生物生物量碳（MBC）的含量。水铝石、水铁矿和锰矿在培养后简化了稻田土壤中 DOM 的分子结构。氧化物特别是锰矿和水铁矿降低了土壤 pH 值和土壤有效氮含量，但增加了土壤氧化还原电位（Eh）。所有被检测的氧化物，特别是铁氧化物，都增加了土壤细菌丰度，但只有锰矿显著影响了细菌组成的门水平。氧化物增强了对易降解有机碳的固定和/或微生物同化作用、调节了土壤基本性质（有效氮、pH 值、Eh 值）、降低了一些分解细菌门（如放线菌）的相对丰度，这些都是氧化物降低 SOM 矿化的潜在途径。
