青藏高原高寒草地3米深度土壤无机碳库及分布特征  

Soil inorganic carbon stock in alpine grasslands on the Qinghai-Xizang Plateau: An updated evaluation using deep cores

作　　者：张蓓蓓[1,2] 刘芳[1] 丁金枝[2,3] 房凯[2,3] 杨贵彪 刘莉[2,3] 陈永亮[2] 李飞[2,3] 杨元合[2] 

机构地区：[1]内蒙古工业大学能源与动力工程学院,呼和浩特010051 [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 [3]中国科学院大学,北京100049

出　　处：《植物生态学报》2016年第2期93-101,共9页Chinese Journal of Plant Ecology

基　　金：国家自然科学基金(31322011和41371213)

摘　　要：准确评估土壤无机碳库的大小及其分布特征有助于全面理解陆地生态系统碳循环与气候变暖之间的反馈关系。然而,由于深层土壤剖面信息匮乏,使得目前学术界对深层土壤无机碳库的了解十分有限。该研究基于342个3 m深度和177个50cm深度的土壤剖面信息,采用克里格插值方法估算了青藏高原高寒草地不同深度的土壤无机碳库大小,并在此基础上分析了该地区土壤无机碳密度的分布特征。结果显示,青藏高原高寒草地0–50 cm、0–1 m、0–2 m和0–3 m深度的土壤无机碳库大小分别为8.26、17.82、36.33和54.29 Pg C,对应的土壤无机碳密度分别为7.22、15.58、31.76和47.46 kg C·m–2。研究区土壤无机碳密度总体呈现由东南向西北增加的趋势;高寒草原土壤的无机碳密度显著大于高寒草甸的无机碳密度。整体上,不同深度的高寒草原无机碳库约占整个研究区无机碳库的63%–66%。此外,深层土壤中储存了大量无机碳,1 m以下土壤无机碳库是1 m以内无机碳库的2倍。两种草地类型土壤无机碳的垂直分布存在差异:对高寒草原而言,0–50 cm土壤无机碳所占的比例最大;但对高寒草甸而言,在100–150 cm深度土壤无机碳出现富集。这些结果表明青藏高原深层土壤是一个重要的无机碳库,需在未来碳循环研究中予以重视。Aims To estimate the size and spatial patterns of 3-m-deep soil inorganic carbon （SIC） stock across alpine grass- lands on the Qinghai-Xizang Plateau. Methods We conducted a comprehensive investigation and collected soil samples from 342 3-m-deep cores and 177 50-cm-deep pits across the study area. Using Kriging interpolation, we interpolated site-level observations to the regional level. The distribution of SIC density was then overlaid with the regional vegetation map at a scale of 1：1 000 000 to calculate SIC stock of the alpine steppe and alpine meadow. Kruskal-Wallis tests were further con- ducted to examine the differences of SIC density between the two grassland types and among soil depths with 50 cm-depth intervals. Important findings The total SIC stock at depths of 50 cm, 1 m, 2 m and 3 m were estimated at 8.26, 17.82, 36.33 and 54.29 Pg C, with SIC density being 7.22, 15.58, 31.76 and 47.46 kg C·m-2, respectively. SIC density exhibited large spatial variability, with an increasing trend from the southeastern to the northwestern plateau. Much larger SIC stock was observed in the alpine steppe than alpine meadow, with the former accounting for 63%456% of the total stock at depths of 50 cm, 1 m, 2 m and 3 m. A large amount of SIC stock was found in deep soils （1-3 m）, amounting to approximately 2 times as much carbon stored in the top 1-m-deep soil layer. The ver- tical distributions of SIC density differed between the two grassland types. The highest proportions of SICoccurred in the upper 50 cm layer for the alpine steppe while the highest proportions occurred in 100-150 cm layer for the alpine meadow. These results highlight that a large amount of SIC is stored in deep soil layers, which should be considered in evaluating terrestrial carbon balance under global change scenario.

关 键 词：碳库 克里格插值 土壤无机碳 3 m土钻 青藏高原 

分 类 号：S812[农业科学—草业科学]