Fig. 8. Depth distribution of soil-gas diffusivities D_p,100/D₀ for Gjorslev and Mammen (field soils) at matric potential = –100 cm H₂O. Average and standard deviation of D_p,100/D₀ at each depth are shown. Predicted D_p/D₀ by the three-porosity model (TPM) are given by dotted and solid lines.