| 内蒙古灌丛化草地取样位置对评估土壤碳氮贮量的影响 |
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| 引用本文： | 柴华,方江平,温丁,李杰,何念鹏.内蒙古灌丛化草地取样位置对评估土壤碳氮贮量的影响[J].草业学报,2014,23(6):28-35. |
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| 作者姓名： | 柴华 方江平 温丁 李杰 何念鹏 |
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| 作者单位： | 1.西藏大学农牧学院,西藏 林芝 860000;2.中国科学院地理科学与资源研究所 生态系统网络观测与模拟重点实验室,北京 100101 |
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| 基金项目： | 国家基础研究发展计划项目，公益性行业科研专项，国家自然科学基金(31270519)资助。 |
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| 摘 要： | 长期过度放牧或不合理放牧使内蒙古草地大面积退化,并出现了以小叶锦鸡儿为主的草地灌丛化现象,显著增加了草地土壤碳氮贮量的空间异质性。如何科学地设置取样点,已成为准确评估该地区灌丛化草地土壤碳氮贮量及其碳汇功能所亟须解决的重要问题。本研究在锡林河流域附近选取了3个不同退化程度的灌丛化草地,分析了灌丛化草地不同位置(灌丛内部、灌丛边缘和灌丛外部)的碳氮含量和贮量的差异。结果表明,灌丛化草地碳贮量在不同取样位置具有较大的差异;以轻度退化草地为例,0~100 cm土壤碳贮量为灌丛内部(8831.26 g C/m2)>灌丛边缘(8174.59 g C/m2)>灌丛外部(7716.48 g C/m2)。如果将灌丛内部、灌丛边缘和灌丛外部分别取样后计算的值作为灌丛化草地土壤碳贮量的真实值,则仅从灌丛内部取样会造成5.74%~27.62%的误差,仅在灌丛边缘取样会造成-3.76%~9.81%的误差,仅在灌丛外部取样的误差为-6.06%~-0.70%。虽然内蒙古地区灌丛化草地的碳氮含量存在显著的空间异质性(或沃岛效应),但由于灌丛面积与土壤碳氮含量在不同程度退化草地内存在密切的负相关关系,因而,从灌丛外部取样的传统方法能准确评估内蒙古地区灌丛化草地的土壤碳氮贮量。
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| 关 键 词： | 内蒙古 小叶锦鸡儿 灌丛 空间异质性 沃岛效应 取样设置 |
| 收稿时间： | 2014-04-30 |
Effect of sampling method on the estimation of soil carbon and nitrogen storages in thicketed semiarid grasslands,Inner Mongolia |
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| CHAI Hua,FANG Jiang-ping,WEN Ding,LI Jie,HE Nian-peng.Effect of sampling method on the estimation of soil carbon and nitrogen storages in thicketed semiarid grasslands,Inner Mongolia[J].Acta Prataculturae Sinica,2014,23(6):28-35. |
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| Authors: | CHAI Hua FANG Jiang-ping WEN Ding LI Jie HE Nian-peng |
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| Institution: | 1.Agriculture and Animal Husbandry College of Tibet University, Linzhi 860000, China;2.Key Laboratory of Ecosystem Network Observation and Modeling, Institute of Geographic Sciences and Natural Resources Research, Chinese Academy of Sciences, Beijing 100101, China |
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| Abstract: | Large areas of grasslands have been subjected to severe degradation in Inner Mongolia because of long-term overgrazing. Thicketization, associated with an increase in Caragana microphylla, on Inner Mongolian grasslands has resulted in an apparent increase in heterogeneity of the distribution of soil nutrients. Consequently, setting up appropriate sampling points is crucial for accurately evaluating storage of soil carbon (C) and nitrogen (N). In this study we selected three grasslands with different levels of thicketization (different levels of degradation) and analyzed the differences in soil C and N from soil sampled from underneath, the canopy edge, and between C. microphylla shrubs. Soil C and N contents differed at different sampling locations. In lightly thicketed grasslands, carbon storage in the 0-100 cm soil layer varied; soil underneath shrub canopies, the canopy edge and between shrubs contained 8831.26 g C/m2, 8174.59 g C/m2 and 7716.48 g C/m2 respectively. Sample variation was greatest under the shrubs, intermediate at the canopy edge and least between shrubs. Our findings suggest that traditional sampling between shrubs can be used to accurately estimate soil C and N content in thicketed grasslands in Inner Mongolia. However, apparent spatial heterogeneity in soil nutrients was found; soil C and N contents were negatively correlated with shrub size in different grasslands. |
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| Keywords: | Inner Mongolia Caragana microphylla shrub spatial heterogeneity fertile island effects sam-pling methods |
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