Tracing Water Recharge and Transport in the Root-Zone Soil of Different Vegetation Types in the Poyang Lake Floodplain Wetland (China) Using Stable Isotopes

Xiuli Xu, Jun Zhao, Guangdong Wu, Yunliang Li () and Lili Hou ()
Additional contact information
Xiuli Xu: School of Geography, Jiangsu Second Normal University, Nanjing 211200, China
Jun Zhao: Coalfield Geological Research of Jiangxi Province, Nanchang 330001, China
Guangdong Wu: Changjiang River Scientific Research Institute, Wuhan 430010, China
Yunliang Li: Nanjing Institute of Geography and Limnology, Chinese Academy of Sciences, Nanjing 210008, China
Lili Hou: Nanjing Centre, China Geological Survey, Nanjing 210016, China

Sustainability, 2024, vol. 16, issue 5, 1-22

Abstract: Background: root-zone water transport is crucial in the water transformation from precipitation to groundwater, directly influencing soil moisture distribution and resource acquisition for wetland plants. Methods: This study investigated the movement mechanism of root-zone (0–80 cm) soil water in the Poyang Lake wetland, China, during a dry year. Hydrological observation and stable isotopes ( δ 18 O and δ D) were utilized. Results: The root-zone soil water content was low (2.9–12.6%) at the high site covered by Artemisia capillaris , while it remained high (25.2–30.2%) at the median and low sites covered by Phragmites australis and Carex cinerascens , respectively. The isotopic values of shallow soil water (0–40 cm) in the A. capillaris site followed the seasonal pattern of rainfall isotopes, indicating predominantly rainfall recharge. Rainfall was primarily transported by piston flow, with an infiltration depth of approximately 60 cm. Conversely, depleted water isotopes measured at certain depths in P. australis and C. cinerascens sites closely resembled those of rainfall, suggesting that preferential flow dominated. The average groundwater contribution proportions in root-zone soil water were 65.5% and 57.4% in P. australis and C. cinerascens sites, respectively, while no contribution was detected in A. capillaris site. Conclusions: Preferential flow and groundwater recharge occurred in the P. australis and C. cinerascens sites. They enhance the hydrological connection at the profile scale and are useful for maintaining a favorable root-zone moisture environment for wetland ecosystems in dry years. However, the hydrological connectivity between root-zone soil and groundwater was found to be obstructed in the A. capillaris site. This might be the main reason for vegetation degradation at high elevations in the Poyang Lake wetland.

Keywords: stable isotopes; root-zone water movement; preferential flow; soil evaporation fractionation; groundwater capillary rise; Poyang Lake wetland (search for similar items in EconPapers)
JEL-codes: O13 Q Q0 Q2 Q3 Q5 Q56 (search for similar items in EconPapers)
Date: 2024
References: View complete reference list from CitEc
Citations:

Downloads: (external link)
https://www.mdpi.com/2071-1050/16/5/1755/pdf (application/pdf)
https://www.mdpi.com/2071-1050/16/5/1755/ (text/html)

Related works:
This item may be available elsewhere in EconPapers: Search for items with the same title.

Export reference: BibTeX RIS (EndNote, ProCite, RefMan) HTML/Text

Persistent link: https://EconPapers.repec.org/RePEc:gam:jsusta:v:16:y:2024:i:5:p:1755-:d:1342848

Access Statistics for this article

Sustainability is currently edited by Ms. Alexandra Wu

More articles in Sustainability from MDPI
Bibliographic data for series maintained by MDPI Indexing Manager ().