Subsoil organic carbon turnover is dominantly controlled by soil properties in grasslands across China
Subsoil organic carbon turnover is dominantly controlled by soil properties in grasslands across China
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中国草地底土有机碳周转主要受土壤性质控制
DOI：
10.1016/j.catena.2021.105654
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发表时间：
2021-03
期刊：
影响因子：
6.2
通讯作者：
Li Jingji
中科院分区：
文献类型：
--
作者：
Shi Yuehong;Tang Xiaolu;Yu Peng;Xu Li;Chen Guo;Cao Longxi;Song Ci;Cai Chunju;Li Jingji
土壤有机碳周转时间（τ，年）是土壤碳稳定性的重要指标，也是决定土壤固碳能力的主要因素。许多先前的研究已经调查了表层中的τ，但对底土τ及其环境驱动因素知之甚少。本文利用野外观测资料估算了中国草原底土τ（底土有机碳（OC）储量与净初级生产力的比值），并采用回归分析和结构方程模型（SEM）研究了气候、土壤和植被变量对中国草原底土τ的影响。结果表明，0.2 ~ 1 m土层的平均τ变化范围为5.5 ~ 702.2年，平均值（±标准差）为118.5 ± 97.8年。不同草地类型的底土τ值差异显著，高寒草甸为164.0 ± 112.0年，高寒草原为107.0 ± 47.9年，温带荒漠草原为177.0 ± 143.0年，温带草甸草原为96.6 ± 88.7年，温带典型草原为101.0 ± 75.9年。底土τ与归一化植被指数、叶面积指数和初级生产力呈显著负相关（p< 0.05）。年平均气温和降水量对τ有负面影响，表明随着气候变化，土壤碳周转更快。基于扫描电镜，土壤性质主要驱动底土τ，挑战了我们目前的认识，并提供证据表明，不同的因素控制表土和底土τ。在这个意义上说，不同的环境因素应考虑可靠地预测土壤碳动态在1米的顶部和底土在区域或全球尺度上的地球化学模型或地球系统模型。
Soil organic carbon turnover time (τ, year) is an important indicator of soil carbon stability and a major factor determining soil carbon sequestration capacity. Many previous studies have investigated τ in the topsoil layers, but little is known about subsoil τ and its environmental drivers. We estimated subsoil τ (the ratio of subsoil organic carbon (OC) stock to net primary production) using field observations from the published literatures and employed regression analysis and the structural equation model (SEM) to identify the effects of climate, soil, and vegetation variables on subsoil τ in China’s grasslands. The results showed that the average subsoil τ over 0.2–1 m varied greatly from 5.5 to 702.2 years, with a mean (±standard deviation) of 118.5 ± 97.8 years. Subsoil τ varied significantly among different grassland types, with 164.0 ± 112.0 years for alpine meadow, 107.0 ± 47.9 years for alpine steppe, 177.0 ± 143.0 years for temperate desert steppe, 96.6 ± 88.7 years for temperate meadow steppe, and 101.0 ± 75.9 years for temperate typical steppe. Subsoil τ was significantly negatively correlated (p< 0.05) with normalized difference vegetation index, leaf area index, and gross primary production. Mean annual (air) temperature and precipitation had a negative impact on τ, indicating a faster turnover of soil carbon with a changing climate. Based on SEM, soil properties mainly drove subsoil τ, challenging our current understanding and providing evidence that different factors control topsoil and subsoil τ. In this sense, different environmental factors should be considered to reliably predict soil carbon dynamics at the top of 1 m and subsoils in biogeochemical models or Earth system models at regional or global scales.
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影响因子：
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作者：
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通讯作者：
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发表时间：
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影响因子：
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