Yang Xin, Zheng Jiao, Yang Dan
College of Life Sciences, Key Laboratory of Plant Resource Conservation and Germplasm Innovation in Mountainous Region, Guizhou University, Guiyang, 550025, China.
Sci Rep. 2024 Oct 10;14(1):23702. doi: 10.1038/s41598-024-75473-3.
The replacement of farmland by native hygro-plants is increasingly common globally within the context of wetland ecosystem restoration. Understanding the long-term effects of this replacement on the abundance and persistence of soil organic carbon (SOC) in mountain marshes is important for soil carbon management. Here, the restored plateau mountain marshes of Duliu River Wetland Provincial Nature Reserve, China was selected. The properties, soil moisture content (SMC), pH, texture, free-form iron oxides ([Formula: see text]), amorphous iron oxides ([Formula: see text]), mineral-associated organic carbon (MAOC), and iron-bound organic carbon (Fe-OC) were analyzed in topsoil samples (0 ~ 20 cm) during the restoration of rice paddies to Sphagnum palustre L. wetlands for 0, 2, 10, and 20 years. Natural Sphagnum wetlands were also used as the control. We found that marsh restoration increased SMC, [Formula: see text], [Formula: see text], [Formula: see text]/[Formula: see text], SOC, MAOC, Fe-OC, Fe-OC/SOC, but decreased the MAOC/SOC ratio. MAOC/SOC ratio of marshes were expectedly lower than the proportion of labile SOC in total SOC during the restoration period. SMC, SOC, and MAOC were higher in the natural Sphagnum wetlands than in other habitats. Both SOC and Fe-OC/SOC were positively correlated with SMC, [Formula: see text], [Formula: see text], [Formula: see text]/[Formula: see text], and Fe-OC, but negatively correlated with soil pH. MAOC/SOC was negatively correlated with SMC, [Formula: see text] and [Formula: see text]/[Formula: see text]. These results emphasized the significance of reconverting rice paddies to marsh wetlands for increasing the sequestration of labile SOC and Fe-OC. Further studies are required to identify and quantify the organo-mineral stabilization mechanisms of SOC at the different SOC fractionations throughout the restoration period.
在湿地生态系统恢复的背景下，用原生湿生植物取代农田在全球范围内越来越普遍。了解这种取代对山地沼泽土壤有机碳（SOC）含量和持久性的长期影响，对于土壤碳管理至关重要。在此，选取了中国都柳江湿地省级自然保护区恢复后的高原山地沼泽。在稻田恢复为泥炭藓湿地0年、2年、10年和20年的过程中，对表土样本（0至20厘米）的性质、土壤含水量（SMC）、pH值、质地、游离态铁氧化物（[公式：见原文]）、无定形铁氧化物（[公式：见原文]）、矿物结合有机碳（MAOC）和铁结合有机碳（Fe-OC）进行了分析。天然泥炭藓湿地也用作对照。我们发现，沼泽恢复增加了SMC、[公式：见原文]、[公式：见原文]、[公式：见原文]/[公式：见原文]、SOC、MAOC、Fe-OC、Fe-OC/SOC，但降低了MAOC/SOC比值。在恢复期间，沼泽的MAOC/SOC比值预计低于总SOC中不稳定SOC的比例。天然泥炭藓湿地的SMC、SOC和MAOC高于其他生境。SOC和Fe-OC/SOC均与SMC、[公式：见原文]、[公式：见原文]、[公式：见原文]/[公式：见原文]和Fe-OC呈正相关，但与土壤pH值呈负相关。MAOC/SOC与SMC、[公式：见原文]和[公式：见原文]/[公式：见原文]呈负相关。这些结果强调了将稻田恢复为沼泽湿地对于增加不稳定SOC和Fe-OC固存的重要性。需要进一步研究来识别和量化整个恢复期间不同SOC分级下SOC的有机-矿物稳定机制。
