Soil Science

What is Good Soil?

Soil is a structure of mineral and organic solids with pore spaces that contain water and gases that can flow through. It's generally agreed that a good quality soil is one that is about 45% mineral, 25% water, 25% gases, and 5% organic material, both alive and dead.

Choosing or mixing the correct soil/dirt mix is not as simple as one would think. One of the most influential aspects of plant nutrition is soil pH because it determines what nutrients are available to the plant. Most nutrients, with the exception of nitrogen, originate from mineral deposits or additives in the mixture. Some nitrogen originates from rain, but most of the nitrogen available in soils is the result of nitrogen fixation by bacteria. Nutrients, which may be stored in soil colloids, teaming with rich nutrient organic matter, however, if pH levels are not correct those pockets of plant food will not be utilized by the plant.

Nitrogen is the most critical element obtained by plants from the soil and is a bottleneck in plant growth if not available. Phosphorus is the second most critical plant nutrient. Lack of phosphorus may interfere with the normal opening of the plant leaf stomata, resulting in plant temperatures 10 percent higher than normal. Phosphorus is most available when soil pH is 5.5 in organic soils.

Following water, the amount and type of organic material is next in importance to soil's formation. Organic material determines the development and the available moisture of soil. Nutrients are derived from the mineral component of the soil with the exception of carbon, hydrogen and oxygen, as they are supplied by carbon dioxide and water.

The organic components in any soil mixture is the reserve of nutrients that can be processed by soil microbes into readily available plant food. Nutrients are carried through soil to the plant in a soil water solution which is absorbed through the roots via osmosis.

In rich organic soils with lots of beneficial soil microbes, certain microbes assist, and in some cases accelerate the rate at which nutrients can be absorbed and processed. As nutrients are used, plants send out roots to find new sources of nutrients while older, less effective roots die back. Bacteria, fungi and certain enzymes reprocess these dead roots back into plant food. Water containing food travels up the stem via capillary action to the leaves, where most of the water is lost by the plant's transpiration and the nutrients are broken down into sugars and other compounds that facilitate healthy plant growth.

What are Soil Micro Organisms?

Micro organism is actually a very broad term. It covers, bacteria, actinomycetes (string-like bacteria), fungi (like mycorrhizae), algae, nematodes, protozoa and even some of the larger critters like arthropods (slugs, millipedes, soil centipedes, etc.) and earthworms.

We like to focus on the beneficial micro organisms, however, bear in mind that there are far more harmful mini critters than helpful ones. Having your soil mix dominated by beneficial microbes tends to dampen and even wipe out the effects of "bad" microbes. The whole idea is to build a working and living soil that assists the plants goal of growing. If your soil is healthy, vibrant and alive, this will lead to plants with the same positive attributes. Superior soil produces the very best produce quality.