In composting, as in the decomposition of any complex substance, the breakdown is a dynamic process accomplished by a succession of microorganisms with each group reaching its peak population when conditions have become optimum for its activity. One group of microorganisms dies and another group thrives until the next incremental change in nutrition and temperature occurs, etc. Composting rate is generally measured by rate of carbon dioxide production. At these temperatures the rate of organic matter decomposition is maximum, and weed seeds and most microbes of pathogenic significance cannot survive. It is important that piles are turned frequently to ensure that all parts are exposed to high temperatures.
Aeration is a key element in composting.
Proper aeration is needed to control the environment required for biological processes to thrive with optimum efficiency. A number of controllable factors are involved. Temperature should be controlled to a 140-150 degrees F upper limit. Above these temperatures even thermophilic microbes either self-destruct or become less effective. Moisture is removed naturally from the compost medium.