Résumé : Soil organic matter (SOM) status was evaluated using the relationships between two independent soil variables, i.e., C respiration and the weight of particulate organic matter POM (4000-50 μm) under different vegetation covers and ecosystems of central Belgium. A positive relationship was found between the weight of the finest POM fraction, i.e., fine POM fraction (250-50 μm) and C respiration after 1 week (R2 = 0.34, n = 120, p < 0.0001) and 2 weeks (R2 = 0.28, n = 120, p < 0.0001) of incubation. Therefore, we assumed that the C respiration and the weight of fine POM might be used to evaluate the SOM status under different vegetation covers and ecosystems. © 2007 Elsevier Masson SAS. All rights reserved.