NOVELTY - The portable composting unit comprises a first initial chamber (16) and a second adjoining chamber enclosed by a pair of opposed sidewalls (20) and a pair of end panels with both the first and second chambers that are capable of holding and decomposing an organic material (12), a separation panel disposed between the chambers and removably mounted to the sidewalls of the chamber, a roof disposed upon the sidewalls and the end panels for generally closing off the chambers, and first and second composting floors disposed within first initial chamber and second adjoining chamber respectively.    USE - The portable composting unit is useful in a system for decomposing organic material (claimed) such as leaves, grass clippings, sticks, limbs, food detritus, animal waste and straw, where the decomposing system is useful in homeowners, farmers, the lawn and garden industry, the specialty produce industry, food manufacturing and processing centers, military and governmental institutions and large-scale composting companies.    ADVANTAGE - The composting unit is towable by a lawn tractor and a vehicle, compact, durable, portable and stackable, and prevents scavengers from entering the chambers.    DETAILED DESCRIPTION - The portable composting unit comprises a first initial chamber (16) and a second adjoining chamber enclosed by a pair of opposed sidewalls (20) and a pair of end panels with both the first and second chambers that are capable of holding and decomposing an organic material (12), a separation panel disposed between the chambers and removably mounted to the sidewalls of the chamber, a roof disposed upon the sidewalls and the end panels for generally closing off the chambers, first and second composting floors disposed within the first initial chamber and the second adjoining chamber respectively, a lifting and tilting mechanism interconnected to the first and second composting floors configured for selectively and independently raising and tilting either composting floor relative to the first and second chambers so that the organic material is transferred between the first chamber and the second chamber or expelled from the composting unit, a first subjacent chamber disposed beneath both composting floors and generally extending the length of the composting floors, and a second subjacent chamber disposed beneath the first subjacent chamber and generally coequal in length with the first subjacent chamber. Each composting floor includes an aeration aperture for allowing air to flow into each respective chamber and about the organic material. A blower is disposed within the first subjacent chamber for directing or extracting air flow up into or from the respective chambers to enhance the decomposition of the organic material. Electronic equipment is configured for monitoring given parameters or conditions occurring within the chambers including ph level, moisture content, temperature or gaseous conditions. Each composting unit is placed upon another composting unit so that respective chambers are brought into alignment for creating a stacked configuration of composting units. An INDEPENDENT CLAIM is included for a portable composting system for decomposing organic material.    DESCRIPTION OF DRAWING(S) - The diagram shows a rear elevational view of a composting system.    Organic material (12)    Composting unit (14)    Initial chamber (16)    Opposed sidewall (20)    Composting floor. (32)