Similar importance of edaphic and climatic factors for controlling soil organic carbon stocks of the world
Similar importance of edaphic and climatic factors for controlling soil organic carbon stocks of the world
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DOI：
10.5194/bg-18-2063-2021
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发表时间：
2021-03-22
期刊：
影响因子：
4.9
通讯作者：
Qian, Tian
中科院分区：
文献类型：
--
作者：
Luo, Zhongkui;Viscarra-Rossel, Raphael A.;Qian, Tian
土壤有机碳（SOC）占陆地碳的三分之二。然而，土壤理化性质在调节SOC储量中的作用尚不清楚，抑制了土地利用和气候变化下可靠的SOC预测。利用来自全球141584个土壤剖面的传统观测数据，我们解开了生物，气候和土壤因素（共31个变量）对SOC储量在4个连续土层中的全球空间分布的影响，下至2米。结果表明，31个变量可以解释土壤有机碳总变异的60%~ 70%，其中气候变量和土壤性质对土壤有机碳总变异的贡献率约为35%（表层20 cm土壤除外）。在表层0-20 cm土壤中，气候的影响比土壤性质的影响大得多（43%对31%），而在20-50、50-100和100-200 cm土层中，气候和土壤性质的影响相似。然而，最重要的个别控制始终与土壤有关，包括土壤质地，水力特性（如田间持水量）和pH值。以净初级生产力、生物群落类型和农业耕作为代表的表观碳输入是次要的，其相对贡献在所有土壤深度中均接近10%。个体土壤特性的这种主导作用挑战了当前气候驱动的SOC动态框架，需要考虑可靠地预测SOC变化，以实现有效的碳管理和减缓气候变化。
Soil organic carbon (SOC) accounts for two-thirds of terrestrial carbon. Yet, the role of soil physicochemical properties in regulating SOC stocks is unclear, inhibiting reliable SOC predictions under land use and climatic changes. Using legacy observations from 141 584 soil profiles worldwide, we disentangle the effects of biotic, climatic and edaphic factors (a total of 31 variables) on the global spatial distribution of SOC stocks in four sequential soil layers down to 2 m. The results indicate that the 31 variables can explain 60 %-70% of the global variance of SOC in the four layers, to which climatic variables and edaphic properties each contribute similar to 35% except in the top 20 cm soil. In the top 0-20 cm soil, climate contributes much more than soil properties (43% vs. 31 %), while climate and soil properties show the similar importance in the 20-50, 50-100 and 100-200 cm soil layers. However, the most important individual controls are consistently soil-related and include soil texture, hydraulic properties (e.g. field capacity) and pH. Overall, soil properties and climate are the two dominant controls. Apparent carbon inputs represented by net primary production, biome type and agricultural cultivation are secondary, and their relative contributions were similar to 10% in all soil depths. This dominant effect of individual soil properties challenges the current climate-driven framework of SOC dynamics and needs to be considered to reliably project SOC changes for effective carbon management and climate change mitigation.