The joint venture between soil food web and clay/humus complex
Ingredients of the clay/humus complex are:
- organic compounds (metabolites of plant and animal materials in various stages of decay),
- gel and glue-like compounds produced by soil microbes and fungi respectively (glomalin!), stabilising notably the smaller soil aggregates,
- a network of fungal threads or hyphae, enabling the formation of bigger-sized soil aggregates,
- fragmented cristalline minerals <50 µm, not weathered yet, without adsorptive properties
- silt and clay particles, <20 µm and <2 µm respectively, with adsorptive properties, able to adsorb and hold nutrients.
All these components together form a colloidal mix with water, a composition that does not dry or leach out as quickly as a simple, aquaeous solution of salts. The reason is that particles and water are attracted/bound by means of weak electrical charges/forces at their boundaries. It means that soils equipped with a good amount of colloids, gel and hyphae are much better resistant against droughts too! It is the home base of the
soil food web, an army of microbes, small soil creatures and worms. This curious colloidal mix receives nutrients from two sources: partly from plant roots exuding sugars and amino acids, and for another part from soil life that brings in organic metabolites locally available in the soil. The green stuff called
chlorofyl assembles sugars and amino acids in plant leaves, with solar energy, CO
2 and N
2 gas drawn from the atmosfere.
Living roots and soil life together are crucial to formation of organic matter!
The organic metabolites in soils are originating from all sorts of decaying organic material called detritus. These metabolites are converted and delivered as organic nutrients by soil life, not only to plants directly, but also by accumulation to the colloidal 'soup', mentioned before, to increase active humus content. You can now imagine how important it is that active soil life is not impeded by pesticides and antibiotics!
