units 30 on engine 28 can vary considerably during operation of the harvester e g as a function of factors including but not limited to crop density moisture content toughness cane diameter etc including significantly over the length of a single swath of a typical field additionally base cutter units 30 operate in cooperation with other elements of harvesting system 36 of harvester 10 such elements generally include crop processing and conveying apparatus 38 of well known construction and operation for receiving the cut canes conveying them onto chassis 12 chopping the canes and holding the chopped canes or conveying them to an accompanying vehicle such as a wagon towed by a truck or tractor 90 fig4 processing and conveying apparatus 38 of harvesting system 36 can be powered directly by engine 28 in any suitable manner such as but not limited to via one or more gearboxes and or transmissions belts chains drive shafts etc or indirectly such as hydraulically by one or more hydraulic motors supplied by pump or pumps 26 driven by engine 28 in the well known manner or otherwise as with base cutter units 30 the resulting torque load on engine 28 can vary substantially during harvesting operations including significantly over the course of travel over a single swath of a field as a function of the above noted conditions such as crop density moisture content toughness etc propulsion system 16 of harvester 10 here is hydraulically powered by fluid motors 40 on.