Journal of East China Normal University(Natural Science) ›› 2021, Vol. 2021 ›› Issue (4): 109-120.doi: 10.3969/j.issn.1000-5641.2021.04.013

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Response of soil greenhouse gas emissions to temperature and moisture across different land-use types

Wenxiu SANG1, Hualei YANG1, Jianwu TANG1,2,*()   

  1. 1. State Key Laboratory of Estuarine and Coastal Research, East China Normal University, Shanghai 200241, China
    2. Institute of Eco-Chongming, Shanghai 202162, China
  • Received:2020-07-30 Online:2021-07-25 Published:2021-07-23
  • Contact: Jianwu TANG E-mail:jwtang@sklec.ecnu.edu.cn

Abstract:

In this paper, soil samples were collected from the red soil region of southern China (namely, the Sunjiaba small watershed in Yingtan, Jiangxi) across four different land-use types. Laboratory incubation experiments were subsequently carried out from June 2019 to October 2019. We used a closed chamber to measure soil greenhouse gases (CO2, CH4, N2O) simultaneously with the help of an advanced greenhouse gas analyzer (Picarro-G2508). The aim was to explore the response of soil greenhouse gas emissions across different land-use types to changes in temperature and soil moisture levels under the premise of global climate change. The results showed that the global warming potential (GWP) of the four land-use types increases with paddy, orangery, forest, and upland, respectively. This suggests that greenhouse gas emissions from paddy soils have the greatest relative impact on global warming. In a temperature-controlled experiment, soil CO2 emissions were shown to have a significant positive correlation with soil temperature. The Q10 values of soil respiration coefficients for the four land-use types were: 2.61 (forest), 2.51 (upland), 3.12 (orangery), and 3.17 (paddy). Thus, paddy soil respiration has the highest temperature sensitivity, indicating that paddy soil has a higher CO2 emission potential. Correlations were not significant between CH4 and N2O emissions to soil temperature. In the moisture-controlled experiment, the results indicated that soil CO2 emissions increased at the beginning and then decreased with increasing soil moisture, with the maximum emission rate at 20% GWC (gravity water content). CH4 emissions from paddy soils increased with soil moisture (R2 = 0.8875); CH4 fluxes from the other three land-use types, however, were not significantly related to soil moisture. The soil N2O emissions increased at the beginning and then decreased across the soil moisture range measured; all land-use types had the highest N2O fluxes at 25% GWC.

Key words: land-use types, greenhouse gas, red soil, temperature, moisture

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