I have written a fairly in-depth guide to the soil food web, and explained why it is the foundation of all sustainable food production. Check it out, and share it with anyone who might benefit from the knowledge!
Here is a section that I think is particularly relevant for permaculture practitioners:
The Factors Influencing Soil Food Web Health (ie. understand these things if you want a healthier soil food web)
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.).
The diversity and size of the microorganism populations are determined by these five factors:
1. The biodiversity of organisms. If a soil is severely disturbed (tilling, heat, chemicals, etc) biodiversity will have to be reintroduced from outside sources. 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.
2. 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)
3. 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).
4. Soil organisms require energy. They get their energy from living plant roots. Plants will put up to 40% of the energy they produce back into the soil as exudates (reference). 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.
5. Microorganisms require 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.
In conclusion, the soil food web becomes healthier:
-the longer it operates undisturbed (increased aeration and oxygen)
-the more organic matter there is in the soil (for water and nutrients)
-the more exudates released by living plant roots (energy)
-and the more diversity in the plants providing those sugars (biodiversity).
It is by controlling those four factors that a Regenerative Farmer is able to do what they do.
Writing about regenerative agriculture is my full-time job. Check out my blog, sheldonfrith.com, it is packed with useful resources. And read my book "Letter To A Vegetarian Nation".
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