Effects of soil process formalisms and forcing factors on simulated organic carbon depth-distributions in soils.
Effects of soil process formalisms and forcing factors on simulated organic carbon depth-distributions in soils.
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DOI：
10.1016/j.scitotenv.2018.10.236
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发表时间：
2019-02
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影响因子：
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通讯作者：
Saba Keyvanshokouhi;Sophie Cornu;F. Lafolie;Jérôme Balesdent;B. Guenet;Nicolas Moitrier;Nathalie Moitrier;Cédric Nougier;Peter;Finke
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文献类型：
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作者：
Saba Keyvanshokouhi;Sophie Cornu;F. Lafolie;Jérôme Balesdent;B. Guenet;Nicolas Moitrier;Nathalie Moitrier;Cédric Nougier;Peter;Finke
土壤有机碳封存（即大气二氧化碳的捕获和长期储存）被认为是缓解气候变化的一种可能解决方案，特别是通过土地利用变化（将耕地转变为牧场）和保护性农业做法（减少耕作）。地下层（从30 cm到1 m）约占土壤有机碳总量的一半，深层有机碳的缓慢动态以及有机碳深度分布与土地利用和耕作方式变化之间的关系仍需要模拟。我们开发了一个完全模块化的机械OC深度分布模型，命名为OC- vgen。该模型包括OC动力学、植物发育、水、气和热的转移、生物扰动混合和耕作作为过程，以及气候和土地利用作为边界条件。OC-VGEN允许我们测试1)根深度分布、分解系数和生物扰动的不同数值表示的影响；2)世纪尺度上土地利用、农业实践和气候等强迫因子对OC深度分布的影响。我们使用该模型模拟了Luvisols不同土地利用（牧场和作物）和耕作方式（传统和减少）的年代际到世纪时间尺度实验，以及2100年气候和土地利用的预测情景。我们发现，在不同的测试形式/参数化中：1)模拟OC深度分布对测试数值表示的敏感性取决于所考虑的土地利用；2)不同的数值表示可以准确地拟合过去的土壤有机碳演变，但当对未来强迫条件（土地利用、耕作方式或气候变化）进行测试时，会导致不同的有机碳储量预测。
Soil organic carbon (OC) sequestration (i.e. the capture and long-term storage of atmospheric CO2) is being considered as a possible solution to mitigate climate change, notably through land use change (conversion of cropped land into pasture) and conservation agricultural practices (reduced tillage). Subsoil horizons (from 30 cm to 1 m) contribute to ca. half the total amount of soil OC, and the slow dynamics of deep OC as well as the relationships between the OC depth distribution and changes in land use and tillage practices still need to be modelled.We developed a fully modular, mechanistic OC depth distribution model, named OC-VGEN. This model includes OC dynamics, plant development, transfer of water, gas and heat, mixing by bioturbation and tillage as processes and climate and land use as boundary conditions. OC-VGEN allowed us to test the impact of 1) different numerical representations of root depth distribution, decomposition coefficients and bioturbation; 2) evolution of forcing factors such as land use, agricultural practices and climate on OC depth distribution at the century scale.We used the model to simulate decadal to century time scale experiments in Luvisols with different land uses (pasture and crop) and tillage practices (conventional and reduced) as well as projection scenarios of climate and land use at the horizon of 2100. We showed that, among the different tested formalisms/parametrizations: 1) the sensitivity of the simulated OC depth distribution to the tested numerical representations depended on the considered land use; 2) different numerical representations may accurately fit past soil OC evolution while leading to different OC stock predictions when tested for future forcing conditions (change of land use, tillage practice or climate).