Monday, September 10, 2012
The Earth is about four and a half billion years old. At first it was a gaseous, spinning, burning object orbiting the sun, along with other similar objects of varying size. However, as the gaseous matter cooled and consolidated, a granite rocky crust would have formed, floating on heavier basalt. These granite crusts eventually formed the continents that are visible today. Further cooling would eventually develop the water and the atmosphere, which are intertwined. Water, ice, wind and gravity would have eroded the parent rock forming a granular material consisting of relative proportions of sand, silt and clay. Also volcanic material, thrust from deep in the earth, spread across the landscape and subsequently eroded under the same factors. These forces in total created an enormous variation in granular material combinations, but not soil.
Somehow this granular, rocky material became inhabited by single celled life forms. When the separation between animal and vegetable single celled life forms occurred is not known. Single celled life was most likely here for a billion years before any more complex life forms developed. It is not known how these first single celled organisms were created or possibly came from or how long they have inhabited the earth since its formation.
The soil forms a thin covering over much of the Earth’s surface. It is a complex material consisting of mineral material (derived from rock), plant roots, water, gases and organic matter in various stages of decay. In this complex mixture live an astounding variety of organisms. These organisms contribute to the soil’s formation, while using the soil as a habitat and a source of energy.
The biology of soil is of fundamental importance to life on Earth, few things matter more. Despite this, little is known concerning what is actually happening in the soil. Dating from ancient times in the Middle East, the Mediterranean, China and India there is a record of man’s interest and concerns for the soil.
Ecologists have long been fascinated by the vast diversity of organisms that live on the Earth. Much of the focus of these studies concerns above ground ecology. Very little is known concerning the diversity of life below ground. The vast numbers of microbes and animals that live in the soil constitute the soil food web, whose primary role is the recycling of organic matter from the above green plant food web.
The primary inhabitants of the soil are the microbes comprised of bacteria, fungi, actinomycetes and algae. They are the main decomposers of organic material in the soil. They are extremely abundant and diverse, inhabiting the most extreme environments and soils. It has been estimated that upward of 10,000 genetically distinct bacterial types can be present in a few handfuls of soil, which may contain 500 billion individuals.
The primary role of bacteria and fungi is to decompose organic materials by means of a vast array of enzymes that they produce. They are capable of breaking down plant support tissues, rich in lignin, returning the material to the nutrient pool in the soil. Most of the nitrogen in the soil is contained in dead, organic matter. Through the action of soil microbes this nitrogen is made available for green plant growth. There is a nitrogen loop in the soil whereby nitrogen is being created in the green plant leaves then enters the soil through decay or exudates from plant roots. However, some bacteria have gained the ability to fix atmospheric nitrogen; this also becomes available to grass plant roots. The fertilizers that we supply are only supplementing this natural system.
Fungi, which are plants that lack the ability to photosynthesize, have other important roles in the soil. They bind soil particles together because of their mycelia network. They also provide a food source for microbes. Some fungi form mutualistic associations with plant roots through their mycorrhiza. This word is derived from the Greek words “mykos” and “riza” and means fungal root. These fungus roots supply nutrients to many types of green plants including grasses. Plants associated with mycorrhizas tend to be more competitive and better able to tolerate environmental stress. In return the fungus gains a supply of nutrients from the green plant.
However, there are also many micro-animals that live in the soil. Such as the amoebas, protozoa and nematodes, which are living on soil bacteria, fungi and each other. The excretions from these tiny animals add to the supply of nutrients in the soil that are available for green plant absorption. It appears that combinations of microscopic plants and animals living in the soil and the amoebas, protozoa and nematodes feeding on the microbes and each other have a synergistic effect on the community of life in the soil. What seems to be happening with the soil life is that each type is playing some role. The big picture is that much of this life in the soil is involved in relationships with green plants, supplying food, imparting resistance to disease and the ability to survive in the physical environment.
Along with the microscopic life in the soil are the insect family known as the microarthropods. The two most abundant members of this group are the mites and the collembolan. Collembola are small, wingless insects with six abdominal segments and biting mouth parts. In grasslands microarthropods can be found in densities of 300,000 per meter. One meter of soil may contain 250 species of mites. Collembola are very specialized feeders on fungus hyphae.
There are also the larger animals that are visible in the terrestrial world and each perform a specific function: the millipedes and woodlice that consumer organic debris, the insect larvae eat plant root material, and the centipedes, spiders, scorpions and beetles which are predators on and in the soil. The ants are one of the largest groups of soil life. They form complex colonies in the soil digging tunnels and chambers as they churn the soil. They have a variety of feeding habits being predators, microbial and plant feeders and opportunistic omnivores. Earthworms are probably the best known of the macrofauna in the soil. They have a great importance in creating a fertile soil and in the aeration of the soil to great depths. Earthworms usually make up most of the biomass in the soil. It is interesting to note that living in the bodies of these soil dwelling animals are the microscopic bacteria and fungi that are digesting the food they consume.
When you consider the vast quantities of life, mostly microscopic, living in the soil, you wonder why such excess? Consider the enormous diversity of genetic types that are involved? It would seem that some overall plan must be working itself out? However, these single celled life forms do not have brains. It must also be remembered that they coat every surface, including us, in the terrestrial world. They are obviously feeding on each other along with the residues of organic matter from plants in the soil.
It would also seem that some strange drama is playing out whereby the numbers of one type increase enormously because the food supply is there or the specific environmental factors of water, air or climate are favorable. Once these specific type or types of organisms have almost exhausted the food supply, their mortality rate increases due to starvation or they fall prey to other microbes that are now, somehow, on the ascendance.
The evolutionary changes in DNA must be influencing these organisms as they adjust in order to better adapt to ever changing variables. So, it would seem, that at the very base of life on Earth there is a war going on between herbivores and predators and between predators and other predators. All trying to capture the other being’s energy.
In a universe of what appears to be limitless size and energy you wonder why this must be so? It must be that the small amount of energy that Earth captures from a single star, our sun, makes this necessary.
There is a circle of life at work in the world. The energy from the sun is used by green plants to create food, which is consumed by the green plants to create their growth and stolen by a host of predators to create theirs. These predators are in effect recycling this energy to be used again to produce more plant growth. These complex interactions between plants and animals are imparting resistances to disease and tolerances to environmental pressures. Our Jonathan Green complex organic fertilizers and soil amendment products are supplementing these natural processes in the soil environment.
“What a piece of work is a man! how noble in reason! how infinite in faculty! in form and moving how express and admirable! in action how like an angel! in apprehension how like a god! the beauty of the world! the paragon of animals! And yet, to me, what is this quintessence of dust?”
-William Shakespeare: Hamlet, Act II, Scene II, Lines 317-323.Back