Earthworms eat their way through our soils and through organic debris, opening up soils, and depositing concentrated, nutrient rich castings on the way. One worm can digest an astonishing amount of soil in a year.
Don’t forget the hundred million to billions of microscopic organisms, represented by thousands of different species, which can occupy a teaspoon of good soil. The microscopic bacteria, fungi, algae, protozoa, and nematodes eat and break down complex organic molecules into forms that plants can use. The microbes capture and hold soluble nutrients like nitrogen and keep them from leaching out of the soil. Other microbes will actually take gaseous nitrogen from the air, fix it, and convert it to plant usable compounds. The humus that these workers produce acts like a storage tank in your soil, holding nutrients and water, and releasing nutrients on a gradual basis much like a slow-release fertilizer. As the soil warms, plant growth begins. Warm soils and moisture boost the activity of microorganisms, who release more nutrients into the soil just in time for the growing plants. All these tiny creatures also produce a natural glue that binds soil particles together to provide a good, porous structure to the soil.
The area right next to the plant roots is called the rhizosphere. Here, the density of microorganisms can be 10 to 20 times greater than in the general soil. Scientists believe that plants actually release a portion, perhaps 10%, of their sugars and other manufactured substances into the soil. The microorganisms are well fed. In return, the microorganisms help the plant in taking up moisture and nutrients. Others protect the plant from soil-borne pathogens. Some soil fungi, called mycorrhizae actually attach to the plant roots. These fungi have long filaments called hyphae that reach out into a large volume of soil and act like an additional root system. The filament-like hyphae, as they push through the soil, can enlarge the surface-absorbing area of the roots 100 to 1,000 fold. The fungal hyphae absorb water and nutrients, including phosphorus and trace minerals for plant uptake. About 80% of plant species have these beneficial root associations with mycorrhizae.
Depending totally on synthetic fertilizers and not restoring organic matter to your soil will decrease the life within the soil, will cause increased leaching and loss of essential nutrients, will decrease water and air holding capacity, and will damage the structure of the soil leading to compaction, poor root growth, and poor plant growth. Restore organic material and life to your soil by adding compost, turning over a cover crop, or using well aged manure. Mulch with an organic material which will eventually decompose. Leaves are free to us in the fall and can be chopped with a lawn mower. Add them to the garden or compost pile. Cut back on the use of insecticides, fungicides, and herbicides. Use the least toxic approach to solving garden problems, and tolerate a bit of holes or spots on your leaves. Most of our industrial pesticides have not been studied enough in detail to determine the effects on soil organisms.
An organically rich, alive soil is a joy to work. Weeds pull out easily. Cultivated plants are transplanted easily and grow well. Look upon soil life as a benefit, rather than as something to be combatted. Continue to feed and improve your soil, and in a short time, the living soil will reward you well.
www.soils.org, Soil Biology
Have fun feeding your soil as it feeds you,