? North Alabama Permaculture Design

Soil Life

Understanding The Relationships Of The Soil Food Web

Soil Biology Is The Heart Of A Productive, Fertile Soil

We, who practice methods of reestablishing the micro-biome within the soil make a distinction between soil and dirt.

Dirt is a lifeless media composed of various mixtures of base mineral constituents of sand, silt and clay, devoid of organic (carbonaceous) matter and essential microbial life. Dirt is commonly found in conventionally (chemically) managed farms, gardens and most residential lawns and urban spaces in general.

Soil is composed of the base mineral constituents, which provide the minerals needed for fertile growing conditions, and additionally, carbonaceous material and a teeming micro-biome consisting of bacteria, fungi, protozoa, nematodes (yes, nematodes are beneficial, more on that later), micro and macro-arthropods, earthworms and more.

Dr. Elaine Ingham, Mr. Jones' teacher and founder of the Soil Food Web Inc. states unequivocally after sampling soils from every region, every soil type, every climate of the world, that in the poorest soil on the planet, even pure sand, there exists all the mineral resources needed to promote healthy, nutrient dense plants if the soil biome were intact.

Understanding A Healthy Soil Nutrient Cycle

It is ironic that almost all "organic" gardeners and farmers don't truly understand how the soil nutrient cycle operates. After at least a couple of generations now since the "green revolution", organic producers have begun thinking like chemical producers. Frequently articles are written, conversations had detailing the need to produce mineral-rich compost to "put minerals back into the soil". This is not a bad practice, it is admirable and beneficial, however it misses the point. "Enriching" the soil with compost is unnecessary and should be thought of as the icing on the cake, rather than the foundation. The most important use of compost is ensuring proper bio-diversity within the soil, which then release bound insoluble nutrients into absorbable forms, as needed, while building proper soil structure for water, air and nutrient retention, without tilling. Have you ever seen a plow or tiller in an untouched, lush and fruitful ecosystem?

What follows is a very "Cliffs Notes" rendition of the interactions of the Soil Food Web.

As previously described, soil is based on a varying mixture of mineral particles, sand, silt and clay. Of these clay is the smallest, it packs tightly together leaving little to no space for water, air, roots or organisms. Anaerobic conditions typically exist in un-floculated clay substrates which accounts for the foul odor often found when digging into clay. Silt is the next larger particle and sand is the largest. A "loam" soil is considered optimal and composed of roughly equal parts sand, silt and clay. A loam soil is, however, not required for a rich and fertile, productive soil.

Anaerobic conditions are the result of soil compaction or / and water-logging. Within anaerobic conditions, beneficial organisms die or become dormant while detrimental organisms thrive. These are the conditions in the “compost” pile which is not properly turned.

Within aerobic conditions beneficial organisms thrive. Bacteria secrete enzymes which bind soil micro-aggregates into the building blocks of proper soil structure, they also produce enzymes which liberate mineral nutrients form the crystalline base aggregates beginning the process of making nutrients available to plants. Actually, plants exude compounds, Dr. Ingham calls “Cakes and Cookies” which promote the types of bacteria needed to provide the particular nutrients needed by the plant, at that time. The plant is absolutely in control. Bacteria are also primary decomposers of organic material.

Fungi are primary decomposers of woody materials. Fungi also bind micro-aggregates into macro-aggregates and dead fungal strands add carbonaceous material to the soil creating favorable soil structures for aerobic conditions promoting more microbial, plant and animal life. Fungal mycelial networks have been shown to cover miles, harvesting needed nutrients for plants from distant locations. In fact, it has been determined that prior to the European invasion of the North American Continent the entire region from the Ozark Mountains to the Atlantic Ocean were connected in one massive mycelial net. Research also shows plants actually communicate, probably chemically, via the mycelial nets.

While bacteria and fungi liberate nutrients from insoluble crystalline mineral particles and dead bodies of organic organisms, they bind them into their own bodies. In order to make nutrients available to plants, various specie of protozoa, nematodes, micro-arthropods, earthworms and the like dine on bacterial and fungal bodies then excreting said nutrients into the soil.

Regarding nematodes. Those familiar with common farming practice no doubt consider nematodes as completely detrimental. Nothing could be further from accurate, for without them a vital portion of the food web is missing and nutrient cycling would seriously slow or stop altogether. There are four main classes of nematodes, classified by their food source; bacterial and fungal feeders, parasitic and root-feeding. The function of bacterial and fungal feeders having already been discussed, releasing nutrients from bacteria and fungi into the soil. Parasitic nematodes dine on other nematodes, their primary food being root-feeding nematodes. Root-feeders are self-explanatory and well known. Due to differences in reproductive cycles, root-feeders tend to withstand nematicide attacks much better than beneficials which has resulted the destruction of the natural balance and the much feared “nematode problem” of the last sixty or so years.

Various species of protozoa, micro and macro-arthropods, worms and other creatures contribute as well to the system consuming low order organisms and releasing those nutrients into the environment.

In summation, left alone soil will self-maintain a porous, non-compacted structure, a thriving healthy biome with copious fertility more than adequate for growth of thriving, healthy nutrient dense plants. Assaults on the natural systems began with agriculture itself. Horticultural societies enhance the soil while agricultural societies destroy it. Monocropping and plowing were the first assaults which soils withstood with some success. The mechanized plow exponentiated the assault, the “green revolution”, with it's salt based fertilizers, bearing too many problems for the scope of this discussion, and then chemical pesticides and herbicides sounded the death knell for a healthy soil food web.

There is a better way, contact Mr. Jones and let him discuss with you how to create your own little bit of self-sustaining, regenerative paradise.

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