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Chinese Journal of Ecology ›› 2021, Vol. 40 ›› Issue (7): 2094-2103.doi: 10.13292/j.1000-4890.202107.007

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Effects of spring rainfall distribution on soil respiration in a coastal wetland of the Yellow River Delta.

MA Shu1,2,3, TAO Bao-xian1, HAN Guang-xuan2,3, WANG Xiao-jie2,3, LI Pei-guang2,3, CHU Xiao-jing2,3*   

  1. (1College of Environment and Planning, Liaocheng University, Liaocheng 252000, Shandong, China; 2Key Laboratory of Coastal Zone Environmental Processes and Ecological Remediation, Yantai Institute of Coastal Zone Research, Chinese Academy of Sciences, Yantai 264003, Shandong, China; 3Yellow River Delta Field Observation and Research Station of Coastal Wetland Ecosystem, Chinese Academy of Sciences, Dongying 257000, Shandong, China).
  • Online:2021-07-10 Published:2021-07-13

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Abstract: Changes of rainfall seasonal pattern would affect carbon cycling in coastal wetlands by influencing the transport of water and salt in soils. Seed germination and plant growth in coastal wetlands are sensitive to rainfall availability in spring, but the underlying mechanism of spring rainfall distribution on soil respiration is still unclear. An insitu spring rainfall control field experiment with five treatments (+73%, +56%, control, -56% and -73% in spring, but the annual total rainfall remained the same) were set up to explore the effects of spring rainfall distribution on soil respiration of a coastal wetland on the Yellow River Delta. Soil water content in spring significantly increased with the increasing rainfall partitioning in spring, while that in autumn significantly decreased. The seasonal variation of soil salinity was opposite to soil moisture, and soil salinity showed strongest fluctuations in spring compared with other seasons. The total belowground biomass and the proportion of belowground biomass in deep soil layer increased with the increasing spring rainfall partitioning, while the proportion of belowground biomass in shallow soil layer showed an opposite pattern. Mean annual soil respiration rate was decreased with the decreasing spring rainfall partitioning, and was significantly different between +73% and -73% treatments (P<0.05). Soil respiration rate differed among different seasons. Soil respiration rate in spring and summer increased with the increasing rainfall partitioning in spring, but decreased in autumn and winter. However, the positive effect of increased spring rainfall partitioning on soil respiration in spring and summer was much greater than the negative effect in autumn and winter. Mean annual soil respiration was closely related to soil moisture and soil salinity in spring, and remarkably affected by the proportion of belowground biomass of different soil layers and total belowground biomass.

Key words: rainfall distribution, soil respiration, water and salt migration, belowground biomass, coastal wetland.