A New Model for Solving Hydrological Connectivity Inside Soils by Fast Field Cycling NMR Relaxometry

In this paper, a new quantitative approach for estimating the structural and functional connectivity inside soil by Fast Field Cycling (FFC) NMR relaxometry is presented, tested measurements carried out in three samples with different texture characteristics. Measurements FFC have been using water-suspended Proton Larmor frequencies (νL) ranging 0.015–35 MHz interval. Two non-degraded samples, textural characteristics, degraded collected badland area, were analyzed. For given any applied frequency, distribution of longitudinal relaxation times, T1, (i.e., relaxogram) measured has integrated, resulting S-shaped curve relaxogram integration curve) was represented, first time, Gumbel’s diagram. This representation curve, transforming into straight line, allowed distinguishing linear components, corresponding to time ranges, characterized slopes. points, identified abrupt slope changes plotted diagram, are used identify two characteristic values T1A T1B, which define well-known pore size classes (T1 < micro-pores, T1 T1B meso-pores, > macro-pores). The calculating non-exceeding empirical cumulative F(T1), values. analysis demonstrated that can be determine pore-size ranges each investigated sample. Finally, components definition Structural Connectivity Index, SCI, Functional FCI, proposed.