Abstract: Unsaturated hydraulic conductivity K(θ) and diffusivity D(θ) of meadow sandy soil in coastal area of North Belgium are determined in situ by internal drainage method, and their empirical formulae are obtained. Covariance analysis shows that there are no significant difference among K(θ) and D(θ) regression equations in differents soil layers of 0-30. 30-60 and 60-90cm, but there is which have a significant difference between these layers and 90-120 cm, layer which should be described by two sets of formulae. No visible difference between power and exponent functions has been found in this study.

Key words: Internal drainage method, Volumetric water content, Hydraulic head, Hydraulic conductivity, Diffusivity, carbon density., carbon storage, forestry carbon sequestration