中国地理科学 ›› 2016, Vol. 26 ›› Issue (4): 518-526.doi: 10.1007/s11769-016-0824-z

• 论文 • 上一篇    下一篇

Diurnal Variation of Soil CO2 Efflux and Its Optimal Measuring Time-window of Temperate Meadow Steppes in Western Songnen Plain, China

YU Xiuli1, LI Xiujun2, XU Linshu1, WANG Ming1,2, ZHANG Jitao2, JIANG Ming2, WANG Guodong2   

  1. 1. Institute for Peat and Mire Research, Northeast Normal University, Key Laboratory of Wetland Ecology and Vegetation Restoration of National Environmental Protection, Changchun 130024, China;
    2. Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
  • 收稿日期:2016-02-26 修回日期:2016-04-15 出版日期:2016-08-27 发布日期:2016-06-21
  • 通讯作者: WANG Ming E-mail:wangm100@nenu.edu.cn
  • 基金资助:

    Under the auspices of National Natural Science Foundation of China (No. 41501090, 41501105), Fundamental Research Funds for Central Universities (No. 2412015KJ023)

Diurnal Variation of Soil CO2 Efflux and Its Optimal Measuring Time-window of Temperate Meadow Steppes in Western Songnen Plain, China

YU Xiuli1, LI Xiujun2, XU Linshu1, WANG Ming1,2, ZHANG Jitao2, JIANG Ming2, WANG Guodong2   

  1. 1. Institute for Peat and Mire Research, Northeast Normal University, Key Laboratory of Wetland Ecology and Vegetation Restoration of National Environmental Protection, Changchun 130024, China;
    2. Key Laboratory of Wetland Ecology and Environment, Northeast Institute of Geography and Agroecology, Chinese Academy of Sciences, Changchun 130102, China
  • Received:2016-02-26 Revised:2016-04-15 Online:2016-08-27 Published:2016-06-21
  • Contact: WANG Ming E-mail:wangm100@nenu.edu.cn
  • Supported by:

    Under the auspices of National Natural Science Foundation of China (No. 41501090, 41501105), Fundamental Research Funds for Central Universities (No. 2412015KJ023)

摘要:

In order to study the diurnal variation of soil CO2 efflux from temperate meadow steppes in Northeast China, and determine the best time for observation, a field experiment was conducted with a LI-6400 soil CO2 flux system under five typical plant communities (Suaeda glauca (Sg), Chloris virgata (Cv), Puccinellia distans (Pd), Leymus chinensis (Lc) and Phragmites australis (Pa)) and an alkali-spot land (As) at the meadow steppe of western Songnen Plain. The results showed that the diurnal variation of soil CO2 efflux exhibited a single peak curve in the growing season. Diurnal maximum soil respiration (Rs) often appeared between 11:00 and 13:00, while the minimum occurred at 21:00-23:00 or before dawn. Air temperature near the soil surface (Ta) and soil temperature at 10 cm depth (T10) exerted dominant control on the diurnal variations of soil respiration. The time-windows 7:00-9:00 could be used as the optimal measuring time to represent the daily mean soil CO2 efflux at the Cv, Pd, Lc and Pa sites. The daily mean soil CO2 efflux was close to the soil CO2 efflux from 15:00 to 17:00 and the mean of 2 individual soil CO2 efflux from 15:00 to 19:00 at the As and Sg sites, respectively. During nocturnal hours, negative soil CO2 fluxes (CO2 downwards into the soil) were frequently observed at the As and Sg sites, the magnitude of the negative CO2 fluxes were 0.10-1.55 μmol/(m2·s) and 0.10-0.69 μmol/(m2·s) at the two sites. The results implied that alkaline soils could absorb CO2 under natural condition, which might have significant implications to the global carbon budget accounting.

关键词: soil respiration, CO2 efflux, meadow steppe, optimal measurement time, negative CO2 efflux

Abstract:

In order to study the diurnal variation of soil CO2 efflux from temperate meadow steppes in Northeast China, and determine the best time for observation, a field experiment was conducted with a LI-6400 soil CO2 flux system under five typical plant communities (Suaeda glauca (Sg), Chloris virgata (Cv), Puccinellia distans (Pd), Leymus chinensis (Lc) and Phragmites australis (Pa)) and an alkali-spot land (As) at the meadow steppe of western Songnen Plain. The results showed that the diurnal variation of soil CO2 efflux exhibited a single peak curve in the growing season. Diurnal maximum soil respiration (Rs) often appeared between 11:00 and 13:00, while the minimum occurred at 21:00-23:00 or before dawn. Air temperature near the soil surface (Ta) and soil temperature at 10 cm depth (T10) exerted dominant control on the diurnal variations of soil respiration. The time-windows 7:00-9:00 could be used as the optimal measuring time to represent the daily mean soil CO2 efflux at the Cv, Pd, Lc and Pa sites. The daily mean soil CO2 efflux was close to the soil CO2 efflux from 15:00 to 17:00 and the mean of 2 individual soil CO2 efflux from 15:00 to 19:00 at the As and Sg sites, respectively. During nocturnal hours, negative soil CO2 fluxes (CO2 downwards into the soil) were frequently observed at the As and Sg sites, the magnitude of the negative CO2 fluxes were 0.10-1.55 μmol/(m2·s) and 0.10-0.69 μmol/(m2·s) at the two sites. The results implied that alkaline soils could absorb CO2 under natural condition, which might have significant implications to the global carbon budget accounting.

Key words: soil respiration, CO2 efflux, meadow steppe, optimal measurement time, negative CO2 efflux