Arid Zone Research ›› 2023, Vol. 40 ›› Issue (8): 1248-1257.doi: 10.13866/j.azr.2023.08.05

• Land and Water Resources • Previous Articles     Next Articles

Effects of flood overflow on soil organic carbon and active components of Populus euphratica forest in the middle reaches of the Tarim River

MA Jilong1,2,3(),SHI Junhui2,3(),WANG Xinying2,3,Aliya BAIDOURELA1,LIU Maoxiu2,3,Aijier ABULA2,3   

  1. 1. College of Forestry and Landscape Architecture, Xinjiang Agricultural University, Urumqi 830052, Xinjiang, China
    2. Research Institute of Afforestation and Desertification Prevention and Control, Xinjiang Academy of Forestry Sciences, Urumqi 830063, Xinjiang, China
    3. Xinjiang Tarim Poplus euphratica Riparian Forest Ecosystem Research Station, Urumqi 830046, Xinjiang, China
  • Received:2023-01-09 Revised:2023-05-06 Online:2023-08-15 Published:2023-08-24

Abstract:

The ecological water transport of the Tarim River increases flood intensity on both sides of the basin, which has an important effect on the carbon cycle of the riparian Populus euphratica forest ecosystems. We studied the P. euphratica forest in the middle reaches of the Tarim River and the content changes of organic carbon and measured and analyzed the active components of the riparian P. euphratica forest at four different stages (1 m before (W1); 4 days after (W2); 17 days after (W3); and after (W4)). We found that the soil organic carbon (SOC) content was higher before and after overflow. The effect of flood overflow on the SOC content in the 0-20 cm soil layer was more significant than that of the 20-100 cm soil layer. During the same stage, the SOC content decreased with soil layer depth. The dissolved organic carbon (DOC) and microbial biomass carbon (MBC) in the 0-10 cm and 40-100 cm soil layers were significantly increased on the 4th day of the overflow compared to before the overflow. The contents decreased gradually with the extension of the overflow time. The differences between each stage were significant (P < 0.05). The DOC/SOC and MBC/SOC in the same soil layer differed significantly as time since the overflow extended (P < 0.05). The extracted organic carbon (EOC) content in the 0-10 cm soil layer before the overflow was higher than after the overflow. The EOC content in other soil layers during the overflow period was higher than before or after the overflow. The EOC/SOC in the 0-10 cm and 20-60 cm soil layers were significantly different at each overflow stage (P < 0.05). There was a significantly positive correlation between SOC and DOC content from before the overflow to day 17 of the overflow (r > 0.69, n = 15) and a significantly positive correlation between EOC and DOC content after discharge (r = 0.54, n = 15). There was a significant correlation between SOC and DOC content before the overflow and at various stages after the overflow. Based on the above analysis, the flooding process in the middle reaches of the Tarim River had a significant effect on the distribution of SOC and the active components of the riparian poplar forest, with differences found in the sensitive soil layers of each component. SOC was most significant in the 0-20 cm soil layer. DOC and MBC were most significant in the 0-10 cm soil layer and the 40-100 cm soil layer, respectively, and EOC was most significant in the 20-60 cm soil layer. Thus, the observed change regularity has the dual characteristics of forest and wetland.

Key words: riparian Populus euphratica forests, flooding, soil organic carbon, active composition, distribution characteristics, Tarim River