抄録
Though mulching with polyethylene film has been commonly used for sweet potato cultivation in Ibaraki prefecture, the film is still removed by hand. Since this is laborious work in a dusty environment, a mulching film remover was developed. First, a series film tension tests was conducted to clarify the maximum applicable tensile force. The results showed that the tear resistances of the films was in the range of 60-155kN, hence the pulling force should be kept below 60N. An experimental self-propelled film remover was constructed and tested in actual fields. During these experiments, films were torn frequently in fields with hard compacted soil, thus we had to test the performance of soil-softening devices. We confirmed that tearing of the film could be prevented by the application of sub soilers, but such sub soilers hindered the operation of farm vehicles.
Based on these results, a tractor mounted film remover was developed. The machine was composed of a main frame, a pair of sub soilers, a film pulling up machine with two rubber rollers rotated by a DC powered motor and a steel rod drum for removing soil from the film. The experimental film remover successfully removed and collected mulching films even in compacted fields, and its field capacities were 1h/10a for film removal and 0.5h/10a for film collection. The field capacities of the film remover were the same as those of manual removal, but operation of the remover requested much less effort that the removal by hand.
