"Compaction"

Definition: "Compaction" is a term applied to soil which, deprived of proper aeration, suffers from excessive water runoff and poor conditions for plant rooting. Soil compaction can be corrected mechanically through core aeration; in nature, earthworms do a good job of working against soil compaction. In reference to compost bins, compaction occurs under anaerobic conditions. Turning a compost pile frequently is one way to avoid such compaction.