Organic Matters-The Soil Food Web

Dirt! Soil! Mud! Quite often referred to as the same living thing. But actually they are, but only by way of it’s basic elements. Soil, comes in many shapes, sizes and variations- The particles that is-and this determines a lot about how that soil affects your food and interacts with the living biomass underground. It has only been in the past 50 years that there has been a a push from farmers and scientists a like to know more about ‘Just what Soil is’ and How it affects us, our planet and other species, that live in that soil.  I don’t know about you, but when I was a kid I was fascinated with soil. All the wriggly animals like worms and millipedes, even little earwigs. This is just what I could see, imagine what else there could be.

As I grew older I unfortunately lost my desire to learn about the soil and put it to one side to get to know myself a bit better. If I had known that the soil would have taught me all i need to know about how life works, then perhaps my life would have taken a different direction. However, I never lost that thirst for curiosity and understanding of our planet, I just stopped looking in the right place and thought my teacher had to come from a human rather than nature itself.

It’s not really until I started growing food, that my fascination with the soil began again. When I started learning about compost, soil and the cycles of growth and decay, I realized that animals like ‘worms’ are not just weird and wriggly and wonderful, they are also essential for soil health and our health, and, also are a key indicator to overall soil health and vitality. It’s the Soil Food Web and the interactions between the numerous different species that will define Soil Health and Life Health. It is quite often said in Regenerative Agriculture, that just those top few inches of soil, give life to the entire planet. That few inches of Organic Matter, does really make the difference between Life and Death on this planet.

SOG (Soil Organic Matter), also known as hummus, is the life blood and beginning of the chemical and biological reactions that kick start the Soil Food Web and cause the interactions of soil life. This is a natural process that has been taking place way before humans were able to understand the soil. It seems that this the importance of this understanding has been left in the dirt and we have forgotten the fundamental connection we have with the soil. This hummus, in nature is formed by leaf litter, decaying fallen branches and trees, animal manure, fungi and decomposing fruit and vegetables. As this ‘Decaying Matter’ is absorbed into the ground a myriad of organisms and creatures strip down the matter and cause further chemical reactions which promote bacteria and fungi to interact with the decaying matter and living matter within the soil. This complex and interwoven relationship, is essentially the most fundamental and important one on this planet. Without this, there would be no life on earth! The relationships that exist within this top few inches of soil determine the health and wealth of our planet. Our Soil Organic Matter provides the food for all life the thrive, the basis for the complex and mutual connections to create more life. Essentially natural death and decay provides the basis both chemically and biologically to create more life.

The composition of soil and the various organisms that make up SOM, all make up the affect on whatever is growing, each of these elements carrying out essential and specific tasks that are all inter-related and equally important. I wanted to introduce you to a few of them and some amazing books and life-long professionals who offer a much more detailed and comprehensive knowledge than I do in this article.

Firstly to give you an idea of the soil composition. Soil is made from minerals, air, water and organic matter (anything that is alive).

45% of this are minerals (sand, silt and clay) salt is very fine particles, clay has very compact particles and silt is somewhere in between. Loam is somewhere between silt and clay and promotes the most fertile soil.

20 to 30% air (this provides the ventilation for the soil to be aerated so it doesn’t become anaerobic.) Worms, especially provide this ventilation.

20 to 30% water. Some soil like sand can either allow to much water to penetrate to quickly through the subsoil, this is a cause of drought. Some soil like heavy clay soil does the opposite, it prevents water from soaking into the subsoil, which causes flooding, especially in heavy downpours. Both of these extremes can also be attributed to bad farming techniques and management of the land. Leaching of nutrients is a sign of soil that’s in need of regeneration.

5 to 10% is organic matter. This is what essentially to a large degree, influences all the other components of soil. The more bio-diverse, natural and undisturbed the hummus is the more of a positive affect it has on the rest of the soil. For instance, when there is more organic matter dead and alive on the surface of the soil, the more it will naturally replicate a living system which is self regulating and constantly seeks harmony and balance. Organic matter promotes better aeration, by way of providing food for worms, which build the tunnels for ventilation, promotes better water retention by way of holding water for the soil to absorb more slowly, which helps both very sandy and heavy clay soil. The minerals in the soil itself, which make up the particle size of the soil and therefore affect it’s water retention are harder to alter, but naturally will vary depending on long climatic changes, can still be influenced by organic matter. Clay, retains some mineral content and can be further improved and altered to more of a loam type soil, which has a higher organic mineral content, which is promoted by a healthy hummus layer.

The humble worm, has 3 hearts, is a hermaphrodite and is able to recycle decaying matter and transform it into humus, just like that. In fact, that’s what they were designed for. Worms are as essential to life on this planet as bees! Underestimated, misunderstood and insanely under-valued, the worm is one of our allies. Having an allotment, I have seen the change in the worm population over the past year and monitored the changes, based on the slight changes I have made. After putting straw down last autumn, I saw an explosion in my worm population, as well as with the other insect and invertebrate life, which attracted birds to be around my plot. Without worms, we wouldn’t have the healthy soil we have in our gardens and allotment plots. If you go onto the land of a commercial farmer in the UK, you may probably find that they will have very few worms in their soil, probably because of the artificial chemicals and fertilizers that have been sprayed on them. What we are doing by using artificial chemicals is not only destroying the home of worms but essentially, we are by this act saying that worms who have been on this planet aren’t good enough at the evolutionary purpose. As usually this shows the ugly parts of human beings, where profit always comes before the planet.

Microbes, our invisible friends, who produce all the nutrients plants need in the soil fight against our invisible enemy, like pathogens and disease, carry out many functions; including, fixing nitrogen, producing antibiotics (like Actinomycetes, a type of bacterium that shares some features of fungus), making organic matter into hummus. The microbes essentially act as traders with the plants roots and exchange for sugary exudates, they give the plant what it needs, either by adjusting the ph balance of the soil, or delivering specific nutrients the plants roots cannot reach. Microbes include, bacteria, fungi and archaea and whatever hasn’t been discovered yet. Some facts about soil microbes:

There are more microbes in a teaspoon of good soil, than there are people on the Earth.

Microbes are responsible for producing hormones that control growth, stress response and immunity levels in animals and plants.

90% of cells in the human body are microbes.

Arthropods, have for a long time had a bad wrap, I still know many people that think they have the right to squash them. Sure, they can be annoying in the house, but for the soil, they are just another essential part of the soil food web. They include: spiders, daddy long legs, centipedes and millipedes and their purpose is to shred organic matter, promoting the growth of bacteria and fungi which they feed on releasing nutrients back into the soil. They also help transport microbes out of their own range, when they were eaten themselves, as well as aerating the soil.

Worth a special mention, is that of Fungi, or specifically Mycorrhizae, this is the mycelium (fungi roots, essentially, that intertwine with plant roots). Probably the most essential connection within the soil, certainly one the most mutually beneficial. This benefits the plants themselves by extending the reach of their roots and therefore their ability to get certain nutrients, in exchange the mycorrhizae feed on the sugars that the roots excrete, which feeds the main fungal body. Nearly all plants have this relationship with mycorrhizae.

Protozoa, the smallest of animals, one celled organisms, were the first to evolve on Earth and include amoebae. They are bigger than the bacteria and fungi they feed on, and some are visible with the naked eye. After digesting the microbes, they release waste back into the soil in the form of nutrients, including any waste nitrogen that they don’t use up. They are essential in the balance of the soil food web and will naturally follow the rise and fall of bacteria populations.

The creatures that live on top of Soil Food Web, are another essential part of the whole system. Animals such as birds, hedgehogs, frogs, toads, newts and perhaps more depending on where you live, are absolutely essential to our soil. They eat unwanted pests, fertilize the plants with their manure and keep the system generally healthy. Remember the hedgehog was prominent within UK back gardens decades ago, and since its decline, they prey that it feeds on like slugs and snails have increased in numbers and now many people use pellets to take the place of the humble hedgehog.

How to create a healthy Soil Food Web?

CEC (Cation Exchange Capacity) is the measure of how many positive ions can be retained on soil particles (negatively charged surfaces). Essentially CEC is a measure of how effectively your soil holds on to distributes nutrients in a way that plants can absorb them to use as energy. The minerals in your soil is made up of both positive and negative charged ions, called Cations and Anions, respectively. The minerals in the soil will be positively or negatively charged-Cations include calcium, magnesium, potassium, ammonium(the plants usable source of nitrogen). Anions include chlorine, nitrate, sulfate and phosphate.

Soils with different mineral content, i.e. sandy or clay soils will have less or more CEC; sandy soils have low CEC, because they are unable to hold onto nutrients as well, due to the particle size being too small. In comparison, clay soils  can hold onto nutrients very well, almost too well, as if it’s too compact, plants can’t access the nutrients. Therefore the application of organic matter, is the solution to improve both soils capacity to hold onto and access the nutrients in soil and provide healthy and abundant food. Nutrients are the result of a myriad of organisms all working together to provide a healthy, bio diverse and balanced community of soil dwellers. Quite a fascinating story in my book. Essentially we all are born from the soil. Our bodies, immunity, evolution and minds are linked to the health of the Soil Food Web. Nature provides us all the answers, all we need do is look and learn.

My own experience of the exploring the Soil Food Web is just one account. If you would like to know more about the amazing and inspiring world of soil, then the following links will shed some wisdom.


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