Journal of Plant Ecology ›› 2021, Vol. 14 ›› Issue (5): 970-980.DOI: 10.1093/jpe/rtab057

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  • 收稿日期:2020-12-31 修回日期:2021-03-03 接受日期:2021-05-11 出版日期:2021-10-01 发布日期:2021-06-11

Effects of pulse precipitation on soil organic matter mineralization in forests: spatial variation and controlling factors

Zhaoxia Jiang1,2, Hongfeng Bian1, *, Li Xu2, Mingxu Li2 and Nianpeng He2,3,4, *   

  1. 1 State Environmental Protection Key Laboratory of Wetland Ecology and Vegetation Restoration, School of Environment, Northeast Normal University, Changchun 130117, China, 2 Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Science, Beijing 100101, China, 3 College of Resources and Environment, University of Chinese Academy of Sciences, Beijing 100049, China, 4 Institute of Grassland Science, Northeast Normal University, and Key Laboratory of Vegetation Ecology, Ministry of Education, Changchun 130024, China

    *    Corresponding author. E-mail: bianhf108@nenu.edu.cn (H.B.); henp@igsnrr.ac.cn (N.H.)
  • Received:2020-12-31 Revised:2021-03-03 Accepted:2021-05-11 Online:2021-10-01 Published:2021-06-11

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摘要： 脉冲降水对森林中土壤有机物矿化的影响：空间变化和控制因素
降水脉冲效应使土壤有机物在短时间内迅速分解并释放大量CO2到大气中。降水脉冲效应对生态系统的碳循环和土壤碳平衡的研究具有十分重要的意义，但它在森林土壤中的空间变化和基本机制仍不清楚。我们采集中国东部22个典型森林生态系统的土壤样品(0–10cm)，研究模拟脉冲降水对土壤微生物呼吸速率的影响。模拟降水脉冲使土壤样品达到65%饱和含水量，以分钟为单位测量Rs，持续48 小时。研究结果显示，降水脉冲可以使微生物呼吸速率迅速增加1.70–38.12倍。微生物最大呼吸速率 (Rs-soil-max)、碳释放总量Rs (ARs-soil)和达到呼吸峰值的时间(TRs-soil-max)在不同的土壤中存在显著差异。此外，不同 气候区的脉冲效应也有明显不同。中温带的Rs-soil-max (11.701 µg C g−1 soil h−1)和ARs-soil (300.712 µg C g−1 soil)最高。土壤化学特性(总碳和总氮、pH值和氧化还原电位)和土壤粒径与森林土壤的脉冲效应密切相关，但土壤微生物的贡献较小。我们的研究结果表明，在大尺度范围内，脉冲变化短期内增加森林土壤中CO2的排放，并揭示了对这种变化影响最大的因素。这些发现为未来对森林生态系统的碳循环和调节全球生态系统碳循环的研究提供科学数据支持。

关键词: 土壤呼吸, 碳矿化, 脉冲效应, 森林, 空间格局

Abstract:

Aims

Pulse effects of precipitation cause soil organic matter to rapidly decompose and release CO2 in a short period. The pulse effects of precipitation are important for ecosystem C cycling and soil C balance, although their spatial variation in forest soils and the underlying mechanisms remain unclear.

Methods

Soil samples (0–10 cm) from 22 typical forest ecosystems in eastern China were used, to investigate the effects of simulated pulse precipitation on soil microbial respiration rates (Rs). We simulated pulsed precipitation to reach 65% water-holding capacity, the Rs was measured on a minute scale for 48 h.

Important Findings

Precipitation pulses can cause a rapid 1.70–38.12-fold increase in the rate of mineralized decomposing organic matter. Maximum Rs (Rs-soil-max), cumulative Rs (ARs-soil) and the time taken to arrive at the maximal Rs (TRs-soil-max) were significant differences among different soil samples. Furthermore, the pulse effects in different climate zones were significantly different. Rs-soil-max (11.701 µg C g−1soil h−1) and ARs-soil (300.712 µg C g−1 soil) were the highest in the mid-temperate zone. Soil chemical properties (total C and, N, pH and oxidation–reduction potential) and soil fractions were strongly correlated with the pulse effects in forest soils, but soil microbes contributed less. Our findings demonstrated that the pulse effects increase forest soil carbon emissions in the short term at a regional scale, and identified the factors with the greatest influence on this change. These findings help guide future studies on the C cycles of forest ecosystems and regulating ecosystem C cycles.

Key words: soil respiration, carbon, mineralization, pulse effect, forest, spatial variation

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