The composting process is a recent technology that contributes to the decrease of environmental pollution by transformation of solid wastes. The final product (compost), which is beneficial for soils and plants, can be used as a soil amendement. Different types of soils in Tunisia, characterized by different climatic zones, are amended by composts. The chemical analyses show the importance of composts in enrichment of soils by major elements and organic matter. The difference is assigned to clay fraction in soils which is more important is calcimagnesic soils.
The study of microstructure in thin sections and the micromorphology revealed the importance of two kinds of organic amendments (compost and manure) and essentially the compost in the association of mineral particles. They constitute an important resources of fertilizing elements and cause the improvement of water reserve and the penetration of roots. The microstructural analyses show the beneficial role of the composts which cover voids between mineral particles and form cutans and plasmic agglomerations. The micromorphological study with the Electron scanning Microscope (ESM) and the data obtained from microanalyses of aggregates confirm the role of composts in soil structuring and their enrichment in mineral elements and reveal the presence of organo-sandy complexes.