Compost windrow turners are used to mix and stir compost material in commercial composting operations. Compost turners, sometimes called windrow turners, are designed to traverse trapezoidal windrows. There are front loader mounted turners where the operator simply drives close alongside the pile and the turner picks the material up, mixes it, then deposits it behind the machine. Self Propelled Compost Turners are straddle machines that work just as their name implies by passing over the compost rows with the compost underneath the machine. Pull Behind Windrow Turners are designed to be pulled by a tractor or loader and may be self powered or may take their power from a PTO on the tractor pulling them. The operator typically drives alongside the pile and the turner aerates and leaves it behind the machine as the operation proceeds. Most operators go with rubber tires, but on soft ground or otherwise marginal conditions, a tracked machine can operate under more severe ground conditions.