Modelling natural burrow systems in soil by fibre process: Monte-Carlo test on independence of fibre characteristics

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• AS_12_n2_237_MON (2,0M)

Abstract

The presence of earthworm burrows in soil has been shown to increase gas diffusion in the soil depth (Kretzschmar and Monestiez, 1992). One of the suspected effects of burrow arrangement on gas diffusion is addressed by the estimation of weighted distances in the burrow system assuming much quicker diffusion through the burrows than in the surrounding soil. The simulations used in previous papers (Monestiez and Kretzschmar, 1989; 1992) were based on Poisson distribution of fibres and on a hypothesis of independence between length and orientation. The present paper focuses on applicability of these assumptions to natural burrow systems. Considering a burrow system as a three-dimensional fibre process, independence assumption of positions of the uppermost points of the fibres was tested using a Monte-Carlo procedure. The latter has been performed conditionally to the empirical distribution of fibre length and orientation. The criterion was based on the weighted distance distribution that is sensitive enough local interactions between fibres. The tests were applied to several natural burrow systems which were described through geometrical characteristics (Kretzschmar, 1988; Kretzschmar and Monestiez, 1987) and showed seasonal variations due to earthworm activities.

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A propos de : Pascal Monestiez

A propos de : André Kretzschmar

A propos de : Joël Chadœuf