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.