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湘东大围山不同海拔带土壤溶解性有机碳含量

马欣,盛浩*,魏亮,潘博,罗兰芳,周清,张杨珠   

  1. (湖南农业大学资源环境学院, 长沙 410128)
  • 出版日期:2016-03-10 发布日期:2016-03-10

Content of soil dissolved organic C along an altitude gradient in Daweishan Mountain of eastern Hunan Province.

MA Xin, SHENG Hao*, WEI Liang, PAN Bo, LUO Lan-fang, ZHOU Qing, ZHANG Yang-zhu   

  1. (College of Resources & Environment, Hunan Agricultural University, Changsha 410128, China)
  • Online:2016-03-10 Published:2016-03-10

摘要: 为了解土壤溶解性有机碳(DOC)含量在中山海拔带上的分异规律,选取亚热带湘东大围山花岗岩风化物发育的典型土壤垂直带谱:红壤、黄壤、黄棕壤和灌丛草甸土(亚类),挖掘土壤剖面深至母质层/母岩,研究海拔和土层深度对DOC含量的影响。结果表明,土壤剖面DOC含量介于9~5326 mg·kg-1,表土(A层)和底土(A层以下)DOC含量均随海拔升高而升高。土壤有机碳(SOC)、水分变化可以解释DOC含量的垂直带分异规律。DOC/SOC介于0.8%~34.9%,无明显的高度带现象,且DOC/SOC峰值大多出现在底土层。在同一海拔带,发育深厚的典型黄壤DOC含量和DOC/SOC均在底土中较高,发育较浅的黄壤性土则相反。本研究表明,表土和底土C含量及组成呈现不同的垂直带分异规律,山地海拔带上土壤C库研究应重视深层底土。

关键词: 冻土, 径向生长, 快速升温, 微地形, 兴安落叶松

Abstract: In order to understand soil dissolved organic C (DOC) content along an altitude gradient in mountain area, soils derived from granite along an elevation gradient (179-1573 m) in Daweishan Mountain of Hunan Province were collected. Soil profiles were excavated down to parent material or rock horizon, and the effects of altitude and soil depth on DOC content were investigated. The results showed that DOC content ranged from 9 to 5326 mg·kg-1, and increased with increasing the altitude both in top soil and subsoil. Soil organic C (SOC) and moisture can well explain the alteration of DOC content along the altitude gradient. DOC to SOC ratio ranged from 0.8% to 34.9%, and was similar at the foot and on the mountain peak. DOC to SOC ratio generally peaked in subsoil. At the same altitude, typical yellow soil with deep B horizon showed higher DOC content and DOC to SOC ratio in subsoil, while yellow soil with indistinct B horizon had lower DOC content and DOC to SOC ratio in subsoil. This study suggests that soil C content and composition varied differently with increasing altitude in top and subsoil. Deep subsoil should be considered in assessing mountain soil C pools.

Key words: radial growth, rapid warming, permafrost, Larix gmelinii, micro-topography