Soil aggregates and humus systems

The survey of few main morphological soil aggregates (with intrinsic biological, chemical and physical contents) reveals the existence of different humus systems. Recognizable by naked eyes in the field, each humus system is confined in an ecological frame (climate, vegetation, substrate and soil) and results from a specific process of plants and soil coevolution. The scope of this cooperation is to implement and store in the soil system a maximum of energy fixed in organic-mineral aggregates. The goal is reached thanks to different humus systems that allow the storage in the soil of organic matter, whose availability is controlled by plants and soil organisms in each given ecological frames. The process may be studied even in anthropic ecosystem, as productive agricultural crops, by comparison with similar but more natural soils. The final slides are dedicated to the presentation of a field manual under publication, in which the main humus systems and forms covering our planet have been illustrated