NOVELTY - A machine (10) comprises a mobile frame adapted for movement over the ground; a central conveyor (20) supported on the frame and oriented to convey material rearwardly and upwardly for discharge from it rearwardly of the conveyor; a header (30) mounted forwardly on the frame to engage and collect the compost material, where the header delivering collected compost material to the central conveyor; and air input apparatus supported on the frame to direct a flow of air onto the conveyor as compost material is being conveyed rearwardly.    USE - For turning and aerating elongated pile of compost material; and for mixing and aerating elongated windrow of compost material (claimed).    ADVANTAGE - The positive displacement of air in the machine provides significant forced aeration of the compost material. The shredding header that engages the original windrow of compost material aggressively shreds the compost material into uniform flow of disintegrated compost material to be re-formed into new windrow. The machine for turning compost windrows is self-propelled with enclosed, environmentally sealed operator's cab. The spacing between windrows of compost material in enclosed shelter is minimized as the machine does not require space between the windrows of compost material to operate. The compost windrow turning and aeration machine is durable in construction, inexpensive of manufacture, carefree of maintenance, facile in assemblage, and simple and effective in use.    DETAILED DESCRIPTION - INDEPENDENT CLAIMS are included for following:    (1) a machine for mixing and aerating an elongated windrow of compost material having device for collecting shredded compost material from the windrow and conveying the shredded material rearwardly of the machine to form a pile of compost material rearwardly of the machine, the improvement comprising: an air input apparatus directed a flow of air into the collected shredded compost material while being conveyed rearwardly of the machine to enhance aeration of the shredded compost material before being placed into the pile rearwardly of the machine;    (2) a compost mixing and aerating machine for engaging an elongated windrow of compost material, mixing and aerating the compost material, and re-depositing the compost material into a pile remote from the elongated windrow, comprising: a mobile frame adapted for movement over the ground; a central conveyor supported on the frame and oriented to convey material rearwardly and upwardly for discharge therefrom rearwardly of the conveyor, the conveyor having shielding defining an enclosed cavity around the central conveyor; a header mounted forwardly on the frame, where the header including a transverse rotor to shred and collect the compost material from the elongated windrow, where the header further including a central discharge opening in register with the central conveyor, where the rotor discharging the collected compost material through the central opening to the central conveyor; and a pair of laterally disposed air ducts oriented angularly to a longitudinal centerline of the machine to direct a flow of air into the enclosed cavity of the central conveyor as compost material, each air duct being associated with a fan to create the flow of air.    DESCRIPTION OF DRAWING(S) - The figure shows right, front perspective view of compost turning and aerating machine.    Machine (10)    Maine frame (11)    Tracks (12)    Central conveyor (20)    Header (30)