Earthworm Burrows and Soil Oxygen Diffusion

This simulation solves a real reaction–diffusion equation — Fick's second law with a microbial consumption sink — on a live 2D grid representing a soil cross-section. Draw your own earthworm burrow network by clicking and dragging directly on the soil: every cell you paint is assigned a much higher diffusion coefficient than the surrounding matrix, so the finite-difference solver computes oxygen penetrating deeper wherever burrows exist. Switch between clay, loam and sand (each with a different bulk diffusivity), tune the microbial respiration rate, or add random burrow tunnels, and watch the mean O₂ saturation, aerobic zone depth and effective diffusivity readouts respond to the actual simulated concentration field in real time.