How Do I Know If I Have Compacted Soil
By pushing a screwdriver into the soil, you can test how compacted your lawn soil may be. If this proves difficult, this would indicate compacted soil. You may also want to remove a square foot of lawn grass. Dig into the soil beneath the turf with a spade, if this proves to be difficult the soil is compacted. The darker soil indicates humus content. The deeper the layer of darker soil, the better for lawn grass growth
It is easy to conceive of soil as a mass of rock particles of varying degrees of fineness. These particles are separated by spaces filled with air and water. Even though soil appears to be solid, about half of its volume consists of spaces filled with air and water. Living within these spaces are soil microorganisms. Bacteria are by far the most numerous constituents; however fungi, protozoa, yeasts and algae are also present in very large numbers. Aside from the microbes, the nematodes, earthworms and insects are also fairly common and important.
There is a direct relation between the amount of organic matter present in the soil and the number of microorganisms. Since a relatively large proportion of the organic matter is present in the upper six inches of the soil, one should find a correspondingly high proportion of microorganisms in the surface area of the soil. There is a gradual increase in the number of microorganisms from early spring to summer and a decrease from late summer to mid-winter due to temperature.
The organic matter in the soil is constantly being devoured by the microbial life of the soil, which depends on it for food. This organic matter, humus, being largely of plant origin, is made up of carbohydrates, proteins, fats, organic acids and other compounds found in plants. Ultimately, organic residues in the soil are reduced to carbon dioxide, water and minerals.
Charles Darwin wrote, “It may be doubted whether there are many other animals which have played so important a part in the history of the world, as have these lowly organized creatures.”
It is the earthworm which continually renews and maintains the valuable top soil. All the waste products of life: the dead vegetation, the manure and the dead animal residues are the chief source of food for earthworms. The actual number of earth worms per acre will vary considerably, according to the quantity of organic matter found in the soil. Darwin found concentrations of from 25,000 to 53,000 per acre. It has been suggested that there could be eight million earthworms in a single acre, and some of their burrows could penetrate to a depth of six feet. One can, therefore, imagine what a tremendous aeration function these creatures would have under these circumstances. The extensive system of tubes which they develop through the soil helps the water penetrate to great depths, as well as giving passage to plant roots and air.
Quoting Charles Darwin again, he wrote, “The whole of the superficial world over any expanse, has passed and will pass again every few years, through the bodies of worms”. No mechanical method of aeration can ever equal this activity. That being said however, in dealing with compacted lawn areas, it is often desirable to core aerate and then work in some form of humus. This will break up some surface compaction and also give the soil life, including the earthworms, something to eat. However, this cannot be considered a long term solution to the problem of soil compaction.
This is where my New American Lawn Plan comes into the picture. By introducing some organic lawn fertilizers, you will be feeding this vast array of life, including earthworms. Also, remember that grass makes top soil. The roots of grass plants are continually penetrating the soil, leaving tiny tubes coated with organic matter left from their own root structure.