NOVELTY - Composting organic waste materials utilizing both aerobic and anaerobic processes simultaneously, comprising forming a cavity in a compost heap of aerobic material and filling it with anaerobic and aerobic material, is new.    USE - The method is useful for transforming organic waste materials into high- quality nutrient-rich soil additives and fertilizers, and may be used for a wide range of composting operations from a single compost pile to commercial scale operations, utilizing compost heaps on scheduled decomposition cycles.    ADVANTAGE - The new method is an improved and accelerated way of composting and decomposition of organic waste materials with reduced offensive odors associated with anaerobic decomposition, and without the need for auxiliary control devices. Furthermore, the leachates produced from the process are filtered and absorbed by the surrounding mass, thus avoiding underground water contamination. The method is cost effective, utilizing inoculants such as bacteria and other microbes indigenous to the materials for composting. Extraneous decomposition-enhancing chemicals or bacterial cultures are not required.    DETAILED DESCRIPTION - Novel composting of organic waste materials comprises:    (a) forming on a solid base, a compost heap of aerobic material;    (b) removing from the top sais heap, a substantial amount of the aerobic material to form an upwardly opening cavity defined by a lower portion spaced from the base and by peripheral sides;    (c) filling a portion of the cavity with a mixture comprising anaerobic and aerobic materials, where the mixture has an upper surface terminating below the top of the heap;    (d) covering the upper surface with a layer of aerobic material to form a lid for the heap;    (e) providing sufficient amounts of aerobic material as the lid and peripheral sides to maintain conditions effective for decomposition of the mixture;    (f) maintaining the mixture undisturbed during the decomposition;    (g) removing the mixture from the cavity and leaving in place the peripheral sides to create a cavity;    (h) refilling the replacement cavity with a new mixture of aerobic and anaerobic material; and    (i) covering the new mixture with a layer of aerobic material forming a new lid for the heap.    DESCRIPTION OF DRAWING(S) - The figure shows a diagramatic view of a compost heap for simultaneous aerobic and anaerobic decomposition.    Compost heap (10)    Control cavity (12)    Anaerobic material (14)    Aerobic material (16)