A composting machine for turning and aerating manure comprises a wheeled frame carrying a tined roller 44 or tined conveyer (not shown) followed by two tined shafts 66 and 68. The roller and shafts all rotate clockwise, viewing the machine from the left, and the tines overlap, the tines on the shafts being of spiral formation (Fig. 5). The machine is driven into one end of a pile of manure, which is disintegrated and conveyed to the tined shafts by rotation of the tined roller. The manure is thrown out of the rear of the machine by rotation of the tined shafts to form a second pile. On completion of composting, the manure is guided to a tranverse conveyer and collected in boxes. One electric drive effects rotation of the tined roller relatively slowly (e.g. at 30 r.p.m.) and also operation of the drive wheels, while a separate electric drive effects rotation of the tined shafts relatively rapidly (e.g. at 400 and 800 r.p.m. respectively) and also operation of a blower 90, which provides jets of air at points 94 and 196 (if necessary) to control flow of fines. Flow to the second pile is guided by means of a hood 80 and adjustable side flaps 36. Water may be injected through the hood via a pipe 98.
