Combined Harvesting of Chaff and Straw for Bioethanol Production: the First Experience on Wheat in Sweden

The purpose of this work is the evaluation of a harvest chain aimed at incorporating the chaff into the straw bales as consequence of wheat harvest operation. The test was performed in August 2017 in Uppsala, Sweden, using a commercial hybrid combine harvester equipped with a modified chaff spreader and a tractor with round baler. In particular, the chaff spreader was used as chaff recovery system to redirect the chaff into the straw flow during its fall on the ground and get the product admixed in the straw swath. The combine was also used with the recovery systems in “spreading mode” to be experimented as control. A few companies are approaching this engineering challenge, however, as the market of agricultural residues for fuel production is growing, simple and affordable solutions should be identified and commercialized. This paper can be considered as a primary attempt to find a simplified and affordable solution in this direction. The results show different harvesting performances according to machine settings. Indeed, when the recovery system was used, the material falling into the swath and baled was about 340 kg (14%) higher per ha (dry basis). However, respect the amount of biomass potentially available for baling, high harvest losses were identified and indicated the need to repeat the test with other machineries and find further adjustments