Chicken soup for the soil
Last updated 3/15/2007 at Noon
What we want to look at now is how to build the organic matter in the soil, enhance soil organisms and covert all this to humus, which is a stable form of carbon that will be bound in the soil, creating life and fertility for decades or even centuries. When we have achieved this, the quality and quantity of production in our gardens will soar.
Organic matter comes in many different forms: straw mulch, leaf mulch, grass clippings, crop residue. The simple sugars that this residue exudes are consumed by beneficial bacteria. The heavy fiber in woody stalks or thicker plants is broken down and consumed by beneficial fungi. This food source allows all these soil organisms to expand and thrive.
After the organic matter is reduced in structure, other larger life forms, beneficial nematodes, arthropods and earthworms consume the rest of the food supply. All these beneficial organisms suppress the bad bacteria, unfavorable fungus and a lot of other plant disease potential in order to keep the soil and the plants healthy. When the soil has a lot of humus it gets loamy and velvety and has a healthy smell. This can take a while to accomplish, but it pays huge dividends.
Cover crops (plants-legumes and grasses) are grown to create another abundant source of organic matter and to draw nitrogen from the atmosphere. In the winter grow peas, fava beans, vetch, lentils and/or clovers with oats or rye grass. Nitrogen-fixing bacteria draw the nitrogen from the atmosphere and deposit it on the roots of the legumes. This is useable form that is available to your next crop. The local farm supply stores have a great variety of these seeds. In the summertime, beans (pinto, black beans, soybeans) with grasses do better in the heat.
When these cover crops achieve a height of two to three feet, cut them at the base and move them aside for the moment. With a spading fork stir the roots of the cover crop. Then with the addition of a good organic fertilizer blend and some good compost spread where the cover crop grew, replace the tops you cut down as a mulch. After about two weeks you can plant vegetable plants right into this bed and they will do fine.
Soil organisms (in sufficient quantities) will break down unavailable minerals bound up in the soil particles into an elemental form that plants can use. The plants will forage for these minerals as it needs them. Some organisms, called mycorizhia, extend the root system of a plant by hundreds of times. They can forage into tiny soil particles too small for the plant roots. They then transfer these minerals to the plant in exchange for simple sugars from the plant that they need to survive. This relationship is called symbiosis. The minerals go into the leaves of the plant and help to create photosynthesis.
All this is a marvelous system that we can nurture to have beautiful gardens and landscapes. By feeding the soil organisms for the long term, they will eat and grow and move through the soil and make it possible to have clean water, clean air, healthy plants and moderated water flow. Love that gardening!