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同树龄杨树(Populus balsamifera)人工林的土壤呼吸空间异质性

闫美芳1, 2**,张新时2,周广胜2   

  1. (1太原理工大学环境科学与工程学院, 太原 030024; 2中国科学院植物研究所植被与环境变化国家重点实验室, 北京 100093)
  • 出版日期:2013-06-10 发布日期:2013-06-10

Spatial heterogeneity of soil respiration in Populus balsamifera plantation at different developmental stages.

YAN Mei-fang1,2**, ZHANG Xin-shi2, ZHOU Guang-sheng2   

  1. (1College of Environmental Science and Engineering, Taiyuan University of Technology, Taiyuan 030024; 2State Key Laboratory of Vegetation and Environmental Change, Institute of Botany, Chinese Academy of Sciences, Beijing 100093)
  • Online:2013-06-10 Published:2013-06-10

摘要:

土壤呼吸作用的空间异质性对土壤碳收支的准确评估起重要作用。通过对新疆伊犁地区3个生长阶段杨树人工林的土壤呼吸速率、土壤环境因子和细根生物量的测定,分析了土壤呼吸速率的空间变异及其影响因素。结果表明:在整个生长季,土壤呼吸空间变异系数(CV)为5.7%~42.6%。2、7和12年生杨树人工林的平均土壤呼吸速率分别为5.74、5.10和4.71 μmol·m-2·s-1,空间变异系数分别为28.8%、22.4%和19.6%,差异显著。逐步回归分析表明,5 cm土壤温度、表层土壤氮含量及细根生物量是决定土壤呼吸空间异质性的主要因子,可以共同解释86%的土壤呼吸变异。此外,由于测点距树干的位置不同,使土壤温度和细根生物量等因子发生了改变,也会导致土壤呼吸的空间变异。在估算杨树人工林土壤碳排放量时,应考虑其在不同生长阶段土壤呼吸速率的空间变异。
 

关键词: 综合风险, 脆弱性, 防灾减灾能力, 干旱, 危险性

Abstract: The spatial heterogeneity of soil respiration plays an important role in accurately evaluating soil carbon balance. Based on the observations of the soil respiration, soil environmental factors, and fine root biomass in poplar (Populus balsamifera) plantations at three developmental stages in Yili of Xinjiang, Northwest China, this paper analyzed the spatial variation of soil respiration and related affecting factors. In the whole growth period of P. balsamifera, the coefficient of variation (CV) of soil respiration ranged from 5.7% to 42.6%. The average soil respiration rate for 2-, 7-, and 12-year old P. balsamifera stands was 5.74, 5.10 and 4.71 μmol·m-2·s-1, and the CV was 28.8%, 22.4% and 19.6%, respectively, with a significant difference in the spatial variation of soil respiration among the three age classes. Multiple regression analysis suggested that the temperature at soil depth 5 cm and the nitrogen content and fine root biomass in upper soil layer were the main factors determining the spatial heterogeneity of soil respiration, responsible for 86% of the variation in soil respiration. In addition, the factors such as soil temperature and fine root biomass changed with the distance from measurement position to tree stem, which could also lead to the spatial variation of soil respiration. It was suggested that the spatial variation of soil respiration at different developmental stages of P. balsamifera should be taken into consideration when evaluating the soil carbon emission in poplar plantations.

Key words: integrated risk, danger, vulnerability, disaster prevention and mitigation capacity., drought