Soil ‚Äì Earth’s Living Layer

Soil is the living layer of the planet. In nature, soil is constantly being created.

Soil begins as rock, which is eroded by wind, rain, water movement and other processes.

This recurring process eventually breaks the rock into small particles, from almost microscopic to easily visible pieces. Rock fragments make up about 45 percent of soil.

The rock itself is an aggregate of minerals, and so are the tiny particles. When dissolved by water (about 25 percent of soil), these minerals become broken down to the molecular level. At this point, the minerals become available to microbes. Add oxygen (the remaining 25 percent) and sunlight to the brew, and the microbes are able to prosper. These microbes continue to break down the minerals in the rock. Living, eating, digesting, evacuating, multiplying and dying, these microbes add more nutrients into the mixture. The living organisms can be bacterial, fungal, or protozoan in origin. The nutrients created by these living organisms (and the organisms themselves) become food for slightly larger, but still mostly microscopic animals, plants and fungi, which go through the same life cycles.

These in turn are consumed by macro-organisms, such as earthworms, larger nematodes, fungal organisms, arthropods and other invertebrates.

Add to this mixture decaying plants, leaves, bodies of larger organisms and other organic material.

The amount of organic matter in soil is about five percent of the total. Therefore, rock fragments constitute 45 percent of soil, organic material five percent and the remaining 50 percent is divided equally between air and water.

The process creates soil, a living layer of earth, rich in nutrients. Plants take these nutrients in through their roots, up through their stems and out into their leaf systems. There, the plants use the nutrients to produce food through photosynthesis. They use other nutrients to enable flowering and seed forming, root expansion and plant growth.

The plants themselves become part of the food chain for larger organisms, as well as providing organic material to add back into the soil.

Each handful of soil contains millions of microbes, hundreds of thousands of protozoans, fungal growths and larger bacteria, thousands of microscopic arthropods, nematodes, and dozens of larger, visible organisms.

In nature, the process of creating soil takes place constantly.

Although plants can be grown without soil (e.g. hydroponics), soil is the natural medium for most plants.

Humans reproduce the natural process of creating soil through a method called composting, a safe and organic way of transforming separate components into living soil, rich in nutrients and capable of correcting many problems that plants encounter.

Related articles include:

1. A Soil Test
2. Soil in a Desert Garden
3. Desert Soils colors and Textures