The health of any soil food web is determined by the diversity and size of the beneficial microorganism populations which are a part of it (bacteria, fungi, nematodes, etc). And the size and diversity of the microorganism populations are determined by the following factors:
- The biodiversity in the ecosystem. How many different species of soil organisms, plants, and animals are present? Each plant will support a different set of organisms (although they are not mutually exclusive) so having a diversity of plant species will also increase the diversity of soil organisms.
- Beneficial microorganisms require oxygen. Oxygen enters soil when the soil is loose. A healthy soil food web creates soil that is naturally loose (no mechanical tilling required).
- Soil organisms also require water. Water is held in soil either by tiny particles of organic matter or by particles of clay. The more organic matter in a soil the more water it can hold (the clay content of a soil cannot be easily changed).13 Looser soil (see #2) allows more rainwater to infiltrate the soil where it can be stored.
- Soil organisms require energy. They get their energy from living plant roots. Plants will put a large portion of the energy they produce back into the soil as exudates. In the absence of living plant roots some microorganisms can live off of the organic matter in the soil and on the soil surface, but many cannot. Even a short period of time without living plant roots will quickly degenerate the soil food web. This is why perennial plants provide more benefit to the soil than annual plants.
- The soil food web requires mineral nutrients. These are provided by bacteria and fungi. The bacteria and fungi get their nutrients either from inorganic rock particles, or from organic matter. It is far easier and faster for them to obtain the nutrients they need from organic matter than from rock particles. Therefore the more organic matter in the soil the less energy plants need to use in order to acquire their nutrients.
The 5 factors influencing soil food web health:
Factor #1: Time passed without disturbance (increased aeration and oxygen)
Factor #2: Organic matter content of the soil (for water and nutrients)
Factor #3: The rate and total amount of energy released by plant roots (exudates)
Factor #4: The diversity of species in the soil and over the soil
Factor #5: The availability and even distribution of water
It is by controlling those five factors that we are able to regenerate soil health.