Journal of Integrative Agriculture

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洞庭湖洪泛平原表层土壤有机碳正在流失—基于十年的野外观测数据

  

  • 修回日期:2025-02-10

Surface soil organic carbon losses in Dongting Lake floodplain as evidenced by field observations from 2013 to 2022

Liyan Wang1, 2, 3, Buqing Wang4, Zhengmiao Deng1, 2#, Yonghong Xie1, 2#, Tao Wang1, 2, Feng Li1, 2, Shao’an Wu4Cong Hu5, Xu Li1, 2, Zhiyong Hou1, 2, Jing Zeng1, 2, Ye’ai Zou1, 2, Zelin Liu6, Changhui Peng6, 7, Andrew Macrae8    

  1. 1 Key Laboratory of Agro-ecological Processes in Subtropical Region, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China

    2 Dongting Lake Station for Wetland Ecosystem Research, Institute of Subtropical Agriculture, Chinese Academy of Sciences, Changsha 410125, China

    3 University of Chinese Academy of Sciences, Beijing 100049, China 

    4 Changsha General Survey of Natural Resources Center, China Geological Survey, Changsha 410600

  • Revised:2025-02-10
  • About author:Liyan Wang, E-mail: 1484311850@qq.com; #Correspondence Zhengmiao Deng, Tel: +86-731-84615206, E-mail: dengzhengmiao@163.com; #Correspondence Yonghong Xie, Tel: +86-731-84615203, E-mail: xyh@isa.ac.cn
  • Supported by:

    This work was supported by the National Key Research and Development Program of China  (2022YFC3204101), the National Natural Science Foundation of China (U22A20570 and U2444221), the Youth Promotion Association of the Chinese Academy of Sciences (2021365), the Changsha Outstanding Innovative Youth Project, China (kq2305035), the Science, Technology and Innovation Platform Plan of  Hunan Province, China (2022PT1010), the Major Scientific and Technological Projects of the Ministry of Water Resources, China (SKS-2022081), and Comprehensive Investigation and Potential Evaluation of Natural Resources Carbon Sink in Southern Hilly Region, China (DD20220880).

摘要: 洪泛平原湿地,气候变化和人类活动导致的水文情势变化可能会降低湿地土壤的碳固存能力,从而对全球气候变化产生负面影响。然而,水文情势变化对土壤碳的影响程度仍然没有得到充分监测。为了弥补这一研究空白,我们在2013年至2022年期间在洞庭湖洪泛区采集了306个表层(0-20cm)土壤样本。采用随机森林(RF)算法分析了洞庭湖表层土壤有机碳(SOC)的空间分布。研究了近十年来气候和水文变化对东洞庭湖表层SOC的影响。2022年,洞庭湖湿地SOC含量范围为3.3417.67 g kg-1之间,平均为10.43 g kg-1,相应的SOC密度为2.65±0.49 kg m-2SOC储量为6.82 Tg C2.87-13.48 Tg C)。2013至2022年,东洞庭湖的SOC含量从18.37 g kg-1下降到10.82 g kg-1这可能是由于气候和水文变化影响了植被生长,从而减少了 SOC 输入并加速了 SOC 分解。高程21.43米以上,土壤有机碳的损失量随着高程的升高而增加,这与南荻群落生物量的下降以及高程高的区域更易受气候和水文变化的影响有关。我们的研究结果强调了加强湿地SOC管理的必要性,以增加土壤中的SOC,从而帮助应对气候变化。

Abstract:

In floodplain wetlands, alterations in hydrological patterns resulting from climate change and human activities could potentially diminish the carbon sequestration capacity of the soils, thereby having a negative impact on global climate change. However, the magnitude of the influence of hydrological regime change on soil carbon remains inadequately monitored. To address this research gap, we collected 306 upper layer (0-20 cm) soil samples from the Dongting Lake floodplain between 2013 and 2022. The Random Forest (RF) algorithm was used to analyze the spatial distribution of soil organic carbon (SOC) in the upper soil layer of Dongting Lake floodplain and the impact of climate and hydrological changes in the past decade on surface SOC in the East Dongting Lake area was studied. In 2022, the SOC concentration of the Dongting Lake floodplain upper layer soil ranged from 3.34 to 17.67 g kg-1, averaging 10.43 g kg-1, with a corresponding SOC density of 2.65±0.49 kg m-2 and total SOC stock of 6.82 Tg C (2.87–13.48 Tg C). From 2013 to 2022, the SOC concentration of the upper soil layer of the East Dongting Lake area decreased from 18.37 g kg-1 to 10.82 g kg-1. This reduction could be attributed to climate and hydrological changes which reduce SOC input by reducing vegetation growth and accelerating SOC decomposition. Above 21.4 m elevation, the amount of SOC loss increasewith elevation, the loss being related to the decline in Miscanthus community biomass and greater susceptibility of higher altitude areas to climate and hydrological changes. Our results highlight the need for strengthening wetland SOC management to increase SOC in the soils to help combat climate change.

Key words: floodplain wetland , soil organic carbon ,  spatial pattern ,  dynamic change