|
| 坡耕地黑土有机碳含量和活性组分的坡面分异规律与影响因素 |
| Spatial variations and determining factors of the quantity and quality of soil organic carbon along the slope of Mollisols in northeast China |
| 投稿时间：2025-02-15 |
| DOI：10.13254/j.jare.2025.0096 |
| 中文关键词: 东北黑土 土壤侵蚀 有机碳 溶解性有机碳 有机碳矿化 |
| 英文关键词: Mollisols in northeast China soil erosion soil organic carbon dissolved organic carbon soil organic carbon mineralization |
| 基金项目:国家重点研发计划项目（2024YFD1500104）；中国科学院战略性先导科技专项（XDA28010302）；国家自然科学基金项目（42477327）；中国科学院青年创新促进会项目（2022313） |
| 作者 | 单位 | E-mail | | 练晶香 | 南京信息工程大学环境科学与工程学院, 江苏省大气环境监测与污染控制高技术研究重点实验室, 江苏省大气环境与装备技术协同创新中心, 南京 210044
中国科学院南京土壤研究所, 土壤与农业可持续发展国家重点实验室, 南京 210008 | | | 黎烨 | 中国科学院南京土壤研究所, 土壤与农业可持续发展国家重点实验室, 南京 210008 | | | 丁佳艺 | 中国科学院南京土壤研究所, 土壤与农业可持续发展国家重点实验室, 南京 210008 | | | 范益恺 | 中国科学院南京土壤研究所, 土壤与农业可持续发展国家重点实验室, 南京 210008 | | | 樊建凌 | 南京信息工程大学环境科学与工程学院, 江苏省大气环境监测与污染控制高技术研究重点实验室, 江苏省大气环境与装备技术协同创新中心, 南京 210044 | jlfan@nuist.edu.cn | | 陈增明 | 中国科学院南京土壤研究所, 土壤与农业可持续发展国家重点实验室, 南京 210008 | | | 丁维新 | 中国科学院南京土壤研究所, 土壤与农业可持续发展国家重点实验室, 南京 210008
中国科学院大学南京学院, 南京 211135 | |
|
| 摘要点击次数: 432 |
| 全文下载次数: 233 |
| 中文摘要: |
| 为探讨有机碳（SOC）含量和性质在坡面尺度上的分异规律与驱动因素，本研究以东北黑土区坡耕地为研究对象，分析不同坡位表层（0~20 cm）和亚表层（20~40 cm）SOC及其活性组分含量，建立培养试验测定SOC矿化速率表征可分解性，进而揭示侵蚀-沉积过程中SOC含量和性质变化规律及其关键影响因素。结果表明，SOC含量沿坡位向下呈先降低后升高的“V”形趋势，在坡中处最低，坡下、坡趾显著高于坡上、坡中；从坡顶到坡中表层和亚表层 SOC的降幅分别为 31.4%和 48.6%，而坡中到坡趾分别增加55.6%和219.5%。土壤易氧化有机碳（ROC）含量在坡面上的分异规律与SOC一致，且变化幅度更为显著。土壤溶解性有机碳（DOC）含量沿坡面也呈先降低后升高的规律，但是表层土壤DOC在坡趾并未显著回升；DOC/SOC沿坡位向下呈不断下降趋势。相反，DOC的芳香度特征值 SUVA254沿坡面向下均呈先升高后降低的趋势，在坡中处最高。表层 SOC可分解性是亚表层的 11.1~17.5倍，均随坡位向下呈整体下降的趋势且在坡趾沉积处最低。SOC可分解性与硝态氮、有效磷、速效钾、DOC、ROC/SOC、DOC/SOC呈显著正相关，与容重、pH、Fe3+则呈显著负相关。随机森林模型表明，DOC含量是影响SOC可分解性最重要的因子。综上，在侵蚀外营力下坡耕地黑土SOC含量和活性同步衰减，坡中是碳丢失的“热区”；而在下部沉积区SOC富集且可分解性低于侵蚀区，有利于土壤碳稳定。基于上述研究，建议在坡耕地土壤管理中重点加强坡上及坡中侵蚀区的碳流失阻控措施，同时对坡下及坡趾沉积区减少人为扰动，最大限度地避免有机碳损失。 |
| 英文摘要: |
| Mollisols in northeast China are predominantly distributed as sloping farmland. The erosion-deposition processes drive the redistribution and loss of soil organic carbon（SOC）, representing a significant factor for the decline of organic matter within these soils. However, the spatial variations of SOC quantity and quality at the slope scale, as well as their driving mechanisms, remain unclear. This study focused on a typical sloping farmland in the Mollisol region, analyzing SOC and its labile components in the surface（0-20 cm）and sub-surface layers（20-40 cm）of different slope positions. This study aimed to explore the patterns and drivers of SOC quantity and quality variations as regulated by the erosion-deposition processes. An incubation experiment was conducted to determine SOC mineralization rates to represent its decomposability. It was showed that the SOC content exhibited a V-shaped trend of decreasing followed by increasing along the slope, and was lowest in the middle of the slope; the decrements of SOC from the top to the middle of the slope in the surface layer and the subsurface layer were 31.4% and 48.6%, respectively; and the increments from the middle to the toe of the slope were 55.6% and 219.5%, respectively. Soil readily oxidizable organic carbon（ROC）content showed the same varying pattern along the slope as SOC, and exhibited a greater changing magnitude. The content of soil dissolved organic carbon（DOC）also showed a V-shaped pattern along the slope, but the DOC content in surface soil did not rise again significantly at the toe of the slope. Consequently, the DOC/ SOC ratio exhibited a decreasing trend along the slope. In contrast, the aromaticity indices of DOC（SUVA254）increased initially and then decreased along the slope, peaking at mid-slope. The decomposability of surface SOC was 11.1-17.5 times higher than that of subsurface SOC and exhibited an overall decreasing trend downslope, with the lowest levels observed in the depositional zones at the toe-slope. The correlation analysis indicated that SOC decomposability was significantly positively correlated with nitrate, available phosphorus, available potassium, DOC, ROC/SOC, and DOC/SOC, while negatively with bulk density and pH. A random forest model identified DOC as the most principal factor influencing SOC decomposability. Collectively, erosion induced synchronized declines in SOC quantity and quality in the sloping farmland of the Mollisols region, with mid-slope areas identified as“hotspots”of SOC loss. In contrast, the lower depositional zones exhibited SOC enrichment with lower decomposability compared with erosion zones, and thus might facilate soil carbon persistence. Based on the above study, it is recommended that the soil management of sloping cultivated land should focus on strengthening the carbon fixation measures in the erosion zone above and in the middle of the slope, and at the same time implement protective measures in the deposition zone below the slope and in the toe of the slope, so as to avoid the loss of organic carbon due to anthropogenic disturbances to the greatest extent possible. |
| HTML
查看全文
查看/发表评论 下载PDF阅读器 |
| 关闭 |
|
|
|
