Extractions

Soil organic matter (SOM) has attracted a great deal of interest and has been the focus of many recent studies because of the potential for soils to store organic matter and mitigate human derived CO₂ emissions. Although recent studies have addressed different aspects of SOM behavior in soils, transport properties of different soil organic matter compounds, which may be directly and/or indirectly related to their stability, are poorly understood, and insufficiently documented. The objectives of the study was to develop a workflow that enables us to 1) Investigate the advective and diffusive mass transport and desorption behavior of the soil organic matter compounds (compare mass transport of different compounds); 2) Measure the extent and rates of the desorption reactions using experimental data from stop-and continuous-flow experiments; 3) Conduct high-resolution imaging inspections and pre-and post-experimental extractions to provide additional insights on soil microporosity control on SOM compound-specific mobility. A series of stop- and continuous-flow column experiments were performed with small diameter intact cores (which allowed for high-resolution imaging) of two representative soil samples collected in a cultivated and an undisturbed/uncultivated area. X-ray computed tomography (XCT) imaging was used to characterize soil porosity and pore network connectivity in the intact cores and Fourier-transform ion cyclotron resonance mass spectrometry (FT-ICR-MS) based analyses were carried out for SOM characterization.