Soil Organisms

Plants, and beneficial soil microorganisms, have a symbiotic relationship with each other. Plants take the Sun's energy and, through photosynthesis, combine it with water and nutrients to form the sugars which become the energy source for all other living organisms, including the microorganisms. About half of the energy produced by plants goes into their root system. About half of that energy is released into the soil. Plants actually feed the microorganisms that improve soil fertility. 

These now well fed microorganisms do a multitude of good things for the plants and soil in return. Just a few examples are: Increasing nutrient availability, reducing salt levels and EC, increasing resistance to diseases and other pests, increasing CEC, reducing soil compaction, improving water infiltration, reducing thatch accumulation, etc.*
Ultimately the plant and the microbes want the same soil conditions. But only the microbes, not the plant, have the ability to directly improve the soil. The end result we are looking for is to provide all the NPK etc. that your plants need AND feed the beneficial microorganisms in the soil at the same time. 

Simply adding more microbes does not do the same thing. If those added microbes could live there, they would already be there. The limiting factor is how many beneficial microbes the soil can sustain. Shifting your fertilization practices to include more organic carbon naturally promotes more microbial activity by increasing the amount of energy available to support them. 

Benefits of Soil Micro-organisms:
1. Nutrient cycling. Increases CEC.
2. Retention of nutrients in the root zone. Nutrients are assimilated and held in the root zone, reducing the loss of nutrients through leaching, run-off and evaporation. 
3. Improved soil structure. Formation and stability of soil aggregates. Increased water infiltration. Reduced compaction. Increased porosity. Increased water holding capacity in sandy soils.
4. Disease suppression. Beneficial microbes suppress pathogenic organisms and shield roots from detection by pathogens.
5. Degradation of pollutants. Breakdown toxins and pollutants. 
6. Increase in Biodiversity. Increases stability of living systems in the soil.

Essential Soil-Borne Organisms:
Soil Inhabiting bacteria can be grouped as decomposers, mutualists, pathogens, or chemoautotrophs. Bacteria that improve the soil quality feed on other microorganisms, decompose organic matter, hold nutrients in the rootzone, improve soil structure, filter and degrade soil contaminants, and compete with disease causing organisms.
Fungi can be grouped as decomposers, mutualists or pathogens. Fungi that improve soil quality decompose complex carbon compounds, improve accumulation of organic matter, retain nutrients in the soil, bind soil particles into aggregates, decompose pollutants and compete with plant pathogens.
Protozoa are single celled organisms that primarily eat bacteria. Protozoa need less nitrogen than bacteria do, and that extra nitrogen is released back to the plants (That's way cool).  Protozoa prevent pathogens from establishing on plants and function as a food source for nematodes. 
Nematodes - (Most species are benefical)
Nematodes are minute, worm-like organisms that live in the film of water in the larger pore spaces in soil. As they travel through the soil, Nematodes distribute the beneficial fungi and bacteria throughout these spaces. Predatory nematodes can consume root-feeding nematodes or prevent thier access to roots. 
Arthropods include such species as centipedes, millipedes, sowbugs, mites, spiders and ants. Arthropods improve soil quality by creating soil structure through burrowing, consuming disease causing organisms, stimulating microbial activity, breaking down organic matter and mixing the soil. They feed on fungi, worms and other arthropods.