Structure and stability of natural organic matter/soil complexes and related synthetic and mixed analogues

This review aimed at the presentation of recent, new approaches which have been developed to improve our knowledge of soil structure and some related characteristics. The investigations reviewed addressed a large number of solid/polymer systems, from strictly synthetic to fully natural systems. Only studies correlating adsorption and solid structuring were considered, so that a great number of adsorption studies were not taken into account.Despite the very complex chemical nature, composition and structure of natural organic matter and soils, some analogues appeared to be useful for determining the role of the natural substances in the stability of soils. Stability means that the soil was able to resist fragmentation and dispersion induced by successive drying and wetting processes. Actually, in the domain of low polymer content, the cohesion of soils was found to be correlated to the concentration of natural organic matter and established by a mechanism which is similar to that inducing the flocculation of suspended colloidal particles. The paper reviews some characteristics of synthetic, natural and mixed systems which display the correlation existing between the structuring of solid agglomerates and the adsorption of polymers.