In gardening, aeration mainly refers to the amount of air that can penetrate through spaces in the soil. Plant roots must have air as well as water and nutrients. Roots are not the only things in the soil which require oxygen. The microbes that help decompose organic matter and make nutrients available to plants also need air. And the macro-organisms like earthworms, insects and other arthropods also need it.
But, since all soils are not created equal, different soils have different qualities. Air can penetrate loamy, organic soils easily. But clay is so fine and the particles so tightly packed together that air cannot easily penetrate to the root systems. Silt particles are also fine, and allow little air to penetrate.
Soil types are not the only factors in preventing air from reaching roots. Soil compaction can force air out of the soil. Soil compaction results from overgrazing of domestic animals, when the action of their hooves continuously compacts the soil, or it can result from mechanical processes, such as during construction of buildings, roadways and parking lots.
Whatever the case, if oxygen cannot reach roots, then plans cannot survive. Therefore it may be necessary to amend soil with other substances to improve aeration and water drainage.
A great way to promote aeration of soil is adding compost. In order to add compost, the soil must be turned, which also helps in aeration of the soil.
Soil aeration in areas such as lawns can be accomplished by dethatching (removing grass thatch), plugging (removing and discarding plugs of grass and soil), or by spiking, which entails punching holes into the soil. All three methods of aeration allow air, water and nutrients to spread through the soil and into the roots. Grass roots must have air as well as water.
In composting, aeration is necessary to promote the growth of beneficial aerobic microbes. (Anaerobic microbes produce harmful methane gas, and other undesirable byproducts.) Compost aeration is accomplished by “turning” the compost, generally taking it from one compost bin and placing it into a second empty bin, one garden forkful at a time. This “fluffs” up the compost and allows air to penetrate and assist in decomposition.
Aeration processes are also used for:
- Secondary treatment of sewage or wastewater.
- Increasing oxygen content of water in aquariums, fish ponds and larger areas such as fish farms.
- Dispelling carbon dioxide and chlorine.
- Pond aeration to prevent mosquitoes from laying eggs.
- Aeration is also used to assist in the fermentation of beer and wine.
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