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Home Composting Slide Show

Thomas Richard, Robert Kozlowski, Nancy Dickson and Roger Kline
July 1989

An updated (2011) PDF version of this slide show is available here.
An updated (2023) PDF version and PowerPoint version of this slide show is available here.

Composting converts waste, leaves, kitchen scraps and garden wastes, into a valuable product which, when used in the garden, results in healthier plant growth when added to garden soil.
Composting can also help solve our society's solid waste disposal problem. Food and yard waste comprise over 30% of our solid wastes nationwide.
This slideshow will introduce you to five basic aspects of home composting: the organisms that are involved in the composting process; manageable components in the composting process; types of materials that can be composted; home composting systems; and uses of compost.

I. Organisms Involved in the Compost Process

Decomposition is a natural part of the nutrient cycle of living things. Composting is simply human intervention to enhance and accelerate the decay process
Composting is a microbiological process. Many organisms have evolved to use decaying matter as their food source. Bacteria are among the simplest and most common organisms. Single-celled and microscopic, they are found almost everywhere in the environment. Although they are too small for us to see, they are responsible for most decomposition. (Special thanks to David Emerson).
Fungi and molds are also important. White rot fungi are well adapted to decompose woody materials like chipped brush.
Mites and other soil invertebrates feed on bacteria and fungi, helping to keep their populations in check. Competition among the different organisms insures that only the most efficient decomposers multiply. (Substitution - slide not available in electronic form).
Earthworms are perhaps the most familiar decomposer. By blending soil and organic matter in their digestive track, they produce stable, nutrient-rich aggregates that improve the structure of soil. (Substitution - slide not available in electronic form. Special thanks to Seattle Tilth Association).
All decomposers are bound together in a complex feeding web. They turn organic wastes into a usable humus for the soil. (Substitution - original slide not available in electronic form).

Continue on with slideshow: Part II. Manageable Components of the Composting Process


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