植物生态学报 ›› 2015, Vol. 39 ›› Issue (12): 1166-1175.DOI: 10.17521/cjpe.2015.0113

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短期施氮肥降低杉木幼林土壤的根系和微生物呼吸

王清奎1,2,,A;*, 李艳鹏1,3, 张方月1,3, 贺同鑫1,3   

  1. 1中国科学院沈阳应用生态研究所森林与土壤生态国家重点实验室, 沈阳 110016
    2中国科学院会同森林生态实验站, 湖南会同 418307
    3中国科学院大学, 北京 100049
  • 出版日期:2015-12-01 发布日期:2015-12-31
  • 通讯作者: 王清奎
  • 作者简介:

    # 共同第一作者

  • 基金资助:
    中国科学院战略性先导科技专项(XDB-150100301和XDA05070305)和国家重点基础研究发展计划(2012CB416905)

Short-term nitrogen fertilization decreased root and microbial respiration in a young Cunninghamia lanceolata plantation

WANG Qing-Kui1,2,*, LI Yan-Peng1,3, ZHANG Fang-Yue1,3, HE Tong-Xin1,3   

  1. 1State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China
    2Huitong National Research Station of Forest Ecosystem, Huitong, Hunan 418307, China
    and 3University of Chinese Academy of Sciences, Beijing 100049, China
  • Online:2015-12-01 Published:2015-12-31
  • Contact: Qing-Kui WANG
  • About author:

    # Co-first authors

摘要:

土壤呼吸是陆地生态系统碳循环的重要过程。在人工林生态系统中, 施肥不仅能提高人工林的生产力和固碳能力, 而且还会对土壤呼吸产生影响。为阐明施氮肥对人工林土壤总呼吸、根系和微生物呼吸的影响, 在中亚热带地区的湖南会同, 以5年生杉木(Cunninghamia lanceolata)幼林为研究对象, 施氮肥1年后, 利用LI-8100对土壤呼吸进行为期12个月的野外原位定点观测。结果发现: 施氮肥使土壤总呼吸、根系呼吸和微生物呼吸分别降低了22.7%、19.6%和23.5%; 土壤呼吸的温度敏感性(Q10)为1.81-2.04, 施肥使土壤微生物呼吸的Q10值从对照的2.04降低为1.84, 但土壤总呼吸的Q10值没有发生显著变化; 施肥没有改变土壤呼吸的季节变化, 在双因素模型中, 土壤温度和含水量可以解释土壤呼吸季节变化的69.9%-79.7%。研究表明施氮肥能降低中亚热带地区杉木人工林土壤有机碳分解对温度升高的响应, 在全球变暖背景下有利于增加土壤有机碳储量。

关键词: 杉木林, 土壤碳释放, 异养呼吸, 施氮肥, 温度敏感性

Abstract:

Aims As the primary pathway for CO2 emission from terrestrial ecosystems to the atmosphere, soil respiration is estimated to be 80 Pg C·a-1 to 100 Pg C·a-1, equivalent to 10 fold of fossil fuel emissions. As an important management practice in plantation forests, fertilization does not only increase primary production but also affects soil respiration. To investigate how nitrogen (N) fertilization affects total soil, root and microbial respiration, a N fertilization experiment was conducted in a five-year-old Cunninghamia lanceolata plantation in Huitong, Hunan Province, located in the subtropical region. MethodsOne year after fertilization, soil respiration was monitored monthly by LI-8100 from July 2013 to June 2014. Soil temperature and water content (0-5 cm soil depth) were also measured simultaneously. Available soil nutrients, fine root biomass and microbial communities were analyzed in June 2013. Important findings Total soil, root and microbial respiration rates were 22.7%, 19.6%, and 23.5% lower in the fertilized plots than in the unfertilized plots, respectively. The temperature sensitivity (Q10) of soil respiration ranged from 1.81 to 2.04, and the Q10 value of microbial respiration decreased from 2.04 in the unfertilized plots to 1.84 in the fertilized plots. However, neither the Q10 value nor the patterns of total soil respiration were affected by N fertilization. In the two-factor model, soil temperature and moisture accounted for 69.9%-79.7% of the seasonal variations in soil respiration. These results suggest that N fertilization reduces the response of soil organic carbon decomposition to temperature change and may contribute to the increase of soil carbon storage under global warming in subtropical plantations.

Key words: Cunninghamia lanceolata plantation, soil carbon emission, heterotrophic respiration, nitrogen fertilization, temperature sensitivity