典型土壤团聚体的多尺度三维孔隙结构和有机碳物理保护机制

土壤团聚体孔隙结构决定了团聚体的许多功能和过程，尤其是物理固碳作用，解剖土壤团聚体内部“黑箱”，是理解其功能和有机碳保护机制的关键。项目以我国不同团聚化过程和土地利用方式的典型土壤为对象，以探明团聚体孔隙结构和物理固碳机制为目标。应用同步辐射显微CT，结合数字图像处理、网络孔隙建模，多维数据融合、拓扑分析及先进图像可视化等方法，以建立团聚体3D孔隙结构原位定量的新方法，探明团聚体内部微尺度孔隙结构及其空间变异规律，阐明土壤团聚体3D孔隙结构和功能的相互关系。应用电镜/能谱和同步辐射傅里叶红外成像探明土壤团聚体中有机碳含量和官能团的空间分布，建立显微CT-电镜/能谱-红外成像多元数据融合方法，探明团聚体对有机碳的物理保护作用，阐明土壤团聚体孔隙结构与有机碳相互关系及有机碳物理保护机制。研究将建立土壤团聚体孔隙结构与有机碳物理保护作用研究的新方法体系，阐明土壤团聚体的物理固碳机制及其固碳潜力。

Pore structure in soil aggregates determines many soil functions and processes occurring in aggregates, especially physically carbon sequestration. To probe into the ‘biogeochemical black boxes’ of intra-aggregates will greatly contribute to better understanding of the mechanisms of soil carbon sequestration in soils. The typical soil types with different aggregation processes and land use as research object, this project will focus on multi-scale three-dimension pore structure and mechanism of physical protection of organic carbon in aggregate. In combination with digit image, pore network model, multi-dimension data fusion, topological structure and image visualization, synchrotron radiation X-ray microcomputed tomography (SR-mCT) is used to describe in situ three-dimension structure and spatial heterogeneity of pore system in aggregates. The application of SR-mCT technique coupled with advanced data analysis is developed as new methodology to probe into and quantify the internal architecture of soil aggregates in three-dimensions at multi-scales. This study will link the three-dimension pore structure to functional characteristics of aggregate in order to understand mechanisms of interaction between pore structure and functions in aggregates. Scanning electron microscopy coupled with an energy-dispersive X-ray spectrometer (SEM/EDS) and synchrotron Fourier transfer infrared (FT-IR) microspectropy SR-FIR imaging will be used to in situ study the composition and functional groups of organic carbon in the soil aggregates. The data fusion that SR-mCT scanning couple with SEM/EDS and SR-FTIR image data will quantify carbon distributions in aggregates for better understanding of carbon sequestration mechanisms. This study will establish the new methodology of understanding pore structure and carbon physical sequestration in aggregate without disrupting the aggregate microstructure. The results will provide quantitative information on relationships between carbon sequestration capacity and pore structure in aggregates. The objective of the study fully understand the mechanisms of how soil aggregates protect SOC, how soil pore structure influences soil carbon storage, or how the C cycles during the process of soil aggregation, and how aggregation affect carbon dynamics.