Measuring the diffusion coefficient of rhizosphere exudates in soil. I. The diffusion of non‐sorbing compounds

SUMMARY A quick, convenient and robust method is presented for measuring the effective diffusion coefficients of non‐sorbing solutes in soil. The method estimates the effective diffusion coefficient from a measured diffusion profile by optimizing the solution of a numerical simulation model describing the experimental system. The method was used to measure the effective diffusion coefficients of compounds found in root exudates.