Five Paradoxes of Soil Hydrology (Observations that quietly undermine equilibrium soil physics)

Unsaturated flow theory is one of the cornerstones of hydrology . For nearly a century, the Richards equation has provided a mathematical framework for describing how water moves through partially saturated soils. At its core lies a powerful simplification: the hydraulic state of soil can be described by water content alone . Yet decades of experiments tell a different story. Across laboratories, field sites, and scales, soil water exhibits behaviors that contradict this assumption in systematic