Anisotropy of subsoil pore characteristics and hydraulic conductivity as affected by compaction and cover crop treatments

The natural and cover crop (CC)‐induced anisotropy of subsoil pore characteristics is important in assessments of soil compaction but, until recently, has received limited attention. This study aims to quantify the anisotropy of soil pore characteristics and hydraulic conductivity in subsoils subjected to compaction and CC treatments in a split‐plot field experiment on temperate sandy loam soils. The main factor was ±compaction and the split‐plot factor was ±CC with fodder radish (Raphanus sativus L.). The compacted plots were heavily trafficked for 4 yr (2010–2013). After 4 yr under CC (2013–2016), core samples were collected at 0.3 m. The samples were taken vertically and horizontally to quantify the anisotropy of air‐filled porosity (εa) and air permeability (ka), saturated hydraulic conductivity (ksat), and bulk density (ρb). The results showed isotropic behavior for ρb and εa and significant anisotropic behavior (p