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氮添加对沙质草地土壤呼吸及其温度敏感性的影响

林力涛1,2,孙学凯1,胡亚林1,3,于占源1,3**,曾德慧1,3   

  1. 1中国科学院沈阳应用生态研究所大青沟沙地生态实验站, 沈阳 110016; 2中国科学院大学, 北京 100049; 3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 110164)
  • 出版日期:2015-06-10 发布日期:2015-06-10

Effects of nitrogen addition on soil respiration and its temperature sensitivity in a sandy grassland.

LIN Li-tao1,2, SUN Xue-kai1, HU Ya-lin1,3, YU Zhan-yuan1,3, ZENG De-hui1,3   

  1. (1Daqinggou Ecological Station, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110016, China; 2 University of Chinese Academy of Sciences, Beijing 100049, China; 3State Key Laboratory of Forest and Soil Ecology, Institute of Applied Ecology, Chinese Academy of Sciences, Shenyang 110164, China)
  • Online:2015-06-10 Published:2015-06-10

摘要: 氮添加能改变土壤微生物代谢和植物根系活性,进而影响土壤呼吸过程。本文以科尔沁沙质草地为研究对象,探讨氮添加对土壤CO2排放的影响。结果表明:1)在观测期7—9月,土壤呼吸日动态呈不对称单峰曲线;氮添加对土壤呼吸日变化有显著影响(P<0.05),与对照(2.18 μmol·m-2·s-1)相比,氮添加后土壤呼吸速率提高了15.2%;氮添加对昼间土壤呼吸的影响显著高于夜间(P<0.05),昼间和夜间土壤呼吸速率增幅分别为17.1%和14.4%。2)土壤呼吸月动态呈先升高后降低的趋势,7月18日达到最大值(3.36 μmol·m-2·s-1);T检验结果表明,氮添加对7、8月土壤呼吸影响达到极显著水平(P<0.01),9月达到显著水平(P<0.05)。3)对照和氮添加的Q10值分别为3.27和3.30,R10值分别为0.42和0.54 μmol·m-2·s-1,说明氮添加增强了沙质草地土壤呼吸对温度的敏感性。

关键词: 阔叶红松林, 择伐干扰, 磷素有效性, 土壤磷, Hedley磷素分级

Abstract: Nitrogen (N) addition can impact root activities and microbial metabolism, thus altering soil respiration rate. In this study we assessed the effects of N addition on soil CO2 flux in a Keerqin sandy grassland during July and September. The results showed that N addition significantly influenced the soil respiration rate. Compared with unfertilized plots (2.18 μmol·m-2·s-1), the respiration rate of Naddition plots was increased by 15.2% and the increment of respiration rate in the daytime (17.1%) was higher than that at night (14.4%). N addition significantly increased soil respiration from July to September. The monthly variation in soil respiration firstly rose then declined, and peaked on the 18th July (3.36 μmol·m-2·s-1). N addition increased the temperature sensitivity of soil respiration and the basal soil respiration, with Q10 values as 3.27 and 3.30, and R10 values as 0.42 and 0.54 μmol·m-2·s-1 in Naddition and unfertilized treatments, respectively.

Key words: Korean pine broad-leaved forest, selective cutting disturbance, soil phosphorus, Hedley phosphorus fractionation, phosphorus availability.