Résumé
This paper synthesises information on the food requirements of soil macroinvertebrates and some of their effects on soil organic matter dynamics. Some clues to techniques that would optimise their activities through organic matter management are suggested. Soil macroinvertebrates can consume almost any kind of organic residues in mutualistic association with soil microflora. Significant amounts estimated at several T per ha of predominantly easily assimilable C are used yearly in natural ecosystems as energy to sustain these activities. Sources of C used are highly variable depending on the feeding regime. The largest part of the energy assimilated (e.g., 50% by the tropical earthworm Millsonia anomala) is actually spent in burrowing and soil transport and mixing. Bioturbation often affects several thousand tons of soil per hectare per year and several tenth of m3 of voids are created in soil. A great diversity of biogenic structures accumulate and their nature and persistance over time largely controls hydraulic soil properties. The OM integrated into the compact biogenic structures (termite mounds, earthworm globular casts) is often protected from further decomposition. Most management practices have negative effects on the diversity and abundance of macroinvertebrate communities. Structures inherited from faunal activities may persist for some weeks to years and the relationship between their disappearance and soil degradation is rarely acknowledged. When SOM supply is maintained but diversity is not, the accumulation in excess of structures of one single category may have destructive effects on soil. It is therefore essential to design practices that provide the adequate organic sources to sustain the activity and diversity of invertebrates. Special attention should also be paid to the spatial array of plots and rotations in time.