Abstract
On the islands of Minami Daitojima and Kita Daitojima in Okinawa Prefecture, an initiative has been launched to replace aging sugarcane harvesters and trucks used for transportation. A variety of proposals have been put forward to downsize equipment and transition to large-scale mechanical systems. The authors set out to develop and formulate an efficient and sustainable model for harvesting and transportation sugarcane on the two islands, starting with organizing basic operational information to systematically classifying the main current systems, which combine harvesting and transportation. The results showed that eight types of harvesters are currently used on Minami Daitojima and Kita Daitojima—one type of large-sized harvester, six types of medium-sized harvesters, and one type of small-sized harvester. We also classified the different ways in which harvesting and transportation operations influence each other; for example, the use of trucks for escorting harvesters as well as for transportation. The effective work rate associated with each pattern was also clarified based on data received from sugar mills, resulting in 19.1-28.0 a/h with large-sized harvesters and 13.3-15.2 a/h with medium-sized harvesters. Our estimation method was verified by examining estimates of effective work rate calculated from real measurements of field work in time trials at sugarcane fields, taking into account the effective work rate measurements obtained from GPS-based analysis of the work performed by transportation trucks.
