Evaluation of two forage harvesting systems for herbaceous biomass harvesting

Machine field efficiency and operating costs are important aspects of biomass harvesting. Two harvesting systems were selected and examined through harvesting alfalfa, wheat straw, and switchgrass. One harvesting system consists of a typical forage harvester and several forage trucks depending on the distance between a field and the dump site; the other system was a self-loading/chopping forage wagon. Both of these systems pick up windrows prepared by a mower and windrow merger or rake. The effects of varying moisture content (10 to 75%) and distance from field to dump site were studied. The systems to be compared were operated in adjoining fields of known acreage. The cycle time, weight of material harvested, and fuel used by each system were recorded. The self-loading wagon system used significantly less fuel and required less man hours to harvest a similar amount of material. The tons of alfalfa per gallon of fuel used to harvest a field 8.5 km (5.3 miles) from the silo were .74 Mg per liter (3.08 tons per gallon) and .33 Mg per liter (1.37 tons per gallon) for the wagon and forage harvesting system respectively. Man hours required to harvest the same field were 42.56 Mg per man hour (46.91 tons per man hour) and 10.31 Mg per man hour (11.37 tons per man hour) for the wagon and forage harvesting system respectively.