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.

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The new cultivation method, which is referred to as the non-training culture with net (popular name: sauvage) method for the open-field cultivation of summer-autumn-harvest cherry tomato, is becoming popular across Japan, no studies have been conducted to compare the workability between the sauvage and traditional cultivation methods. The present study compared sauvage and traditional cultivation methods, focusing on the time required to perform each task, postures assumed to perform them, and yields, to establish the sauvage cultivation system. In sauvage cultivation, the time required to perform each task (training and chemical spraying in particular) was significantly shorter than in traditional cultivation methods, except for the time for harvest. However, the time required for the harvesting of cherry tomatoes in sauvage cultivation method accounted for 90% of the total time for all cultivation processes and the percentage was drastically higher than that of traditional cultivation methods. The yield per unit area in sauvage cultivation, in which the planting density was lower, was similar to or larger than the yield in traditional cultivation methods, and the growers were able to ship their crops in August to September when the plants would have been exposed to high temperatures and solar radiation level. Sauvage cultivation can be expected, as a new method for the open-field cultivation of summer-autumn-harvest cherry tomatoes to promote labor-saving in relation to their cultivation management. To reduce the time required to perform each task, improving harvest procedures accounted for majority of total time for all cultivation processes was considered to be necessary.

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Asparagus (Asparagus officinalis L.) is a high value vegetable, rich in bioactive factors such as rutin, saponin, polysaccharide, and organic selenium. At present, China is the largest asparagus production country in the world. Due to the quick expansion in acreage over the last two decades, asparagus has become a huge industry in China. In the early 1990’s, China was an asparagus exporter, especially can processing, and white asparagus was mainly grown in plantation areas. From the mid-90’s, green asparagus production increased step by step because of the demand for fresh green eating and many kinds of processing products such as tea, juice, medicine, and powder. These changes led to increasing domestic usage of harvest spears and reduction of exports. To increase the asparagus yield and productivity, white asparagus cultivation was changed to green production mainly in the northern, cool region of China. On the other hand, the long-term production system called mother-fern cropping in plastics has been started mainly in the middle and southern part of China. Around three-month old seedlings were used for transplantation in plastic house. The method of transplantation and harvest basically depends on manual labor. Spray irrigation and drip irrigation system were performed for management of soil water. The hot temperature was controlled by covering the sunshade net in summer. The white asparagus production decreased because of the world economic crisis in 2008 and recovered after 2009. The most serious disease was called stem blight, which has been considered as one important limiting factor for sustainable development, especially in southern China. A national project was launched to breed a domestic cultivar with resistance to stem blight disease.

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[in Japanese]

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