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Volume 48 (2013)
- Issue 4 Pages 133-
- Issue 3 Pages 103-
- Issue 2 Pages 49-
- Issue 1 Pages 1-
Volume 48, Issue 4
Displaying 1-4 of 4 articles from this issue
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Original Papers
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Kohei TASAKA, Takashi WADA, Yoichi YUSA, Kazuhiro YOSHIDA, Toshihiro A ...2013 Volume 48 Issue 4 Pages 133-141
Published: December 20, 2013
Released on J-STAGE: June 20, 2014
JOURNAL FREE ACCESSThe apple snail, Pomacea canaliculata (Lamarck), was introduced to Japan from South America as food for humans about thirty years ago. It is now a threat to the spread of direct-sown rice in Kyushu, southern Japan. Here we studied the use of a newly developed repellent paint containing fine copper powder to control the spawning of apple snails living in waterways. First, the repel-lent paint was applied to a concrete wall of the waterway in a narrow band (10 cm in width) just above the water surface. However, it was not effective due to the fluctuations of the water level. Then, the repellent paint was applied in a broader band (50 cm in width), and the effect was tested for three years. No egg masses were laid on the concrete wall painted with the repellent, indicating that the repellent controlled the spawning of apple snails. However, the density of the apple snails in the areas where the repellent was applied did not decrease compared to the areas without the repellent. The main reason could be that the size of the repellent areas was so small that the snails moved across the areas.View full abstractDownload PDF (455K) -
Akitsugu KOIZUMI, Yoko MIYAMA2013 Volume 48 Issue 4 Pages 143-148
Published: December 20, 2013
Released on J-STAGE: June 20, 2014
JOURNAL FREE ACCESSIn this study, the utility of salivary biochemical parameters that have been known to indicate mental workload in humans for assessing mental workload from farm labor was studied. The farm labor included harvesting and binding komatsuna (Brassica rapa L. Perviridis Group). Saliva samples were taken during a 120-minute period of labor and performed quantitative analysis of salivary α-amylase, cortisol, dehydroepiandrosterone and immunoglobulin A to identify the occurrence of any changes in these parameters with farm labor. It was found that α-amylase activity was increased significantly with farm work. These results suggest that α-amylase activity could serve as an effective evaluation index for assessing mental workload from farm labor.View full abstractDownload PDF (508K) -
Kentaro MATSUO, Mikio YASHIRO2013 Volume 48 Issue 4 Pages 149-156
Published: December 20, 2013
Released on J-STAGE: June 20, 2014
JOURNAL FREE ACCESSA new seeder was designed and built to ease thinning by placing the seeds at correct intervals. The performance of this seeder was evaluated. The seeder consisted of 2 conveyor belts for transporting seeds, a chisel furrow opener, a covering plate and a ground-contact drive wheel. The 2 conveyor belts were stacked one on top of the other. A hole in the upper conveyor belt picked up one of the seeds, then transferred to a larger hole in the lower conveyor belt, and released at a low position. The laboratory experimental setup was as follows : the new seeder, a commercial belt seeder, and a commercial vacuum seeder were mounted on the motors that were fixed on stands. This setup was driven at a working speed of 0.56 m/s. For sowing pelleted carrot seeds by using the new seeder, the seed spacing interquartile range (IQR) was found to be 8.4 mm, which was lower than half the IQR for a commercial belt seeder. In case of spinach seeds, the new seeder showed an IQR of 8.6 mm, which was less than a third of the IQR displayed by both the commercial seeders. In case of Japanese radish seeds, the new seeder showed an IQR of 12.6 mm, which was also less than the IQR presented by both the commercial seeders. During field trials, while sowing 3 seed types, the new seeder showed an IQR less than the IQR displayed by both the commercial seeders.View full abstractDownload PDF (414K)
Research Paper
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Mitsuhiko KATAHIRA, Sei ITO2013 Volume 48 Issue 4 Pages 157-164
Published: December 20, 2013
Released on J-STAGE: June 20, 2014
JOURNAL FREE ACCESSIn this study, we evaluated the effects of labor saving technology on the cultivation of ‘Kanakabu’ turnip, a domestic variety cultivated using a slasburn method in Akita Prefecture. Power tillers were evaluated on a test field with a 10-meter elevation difference and a 14.0 degrees average gradient. Work rates were 47 h/10a in conventional blocks using a hoe and 6 h/10a in power farming blocks using power tillers, representing an 87% labor saving rate. The power-farming block showed increased germination of 36 hills/m2, compared to the conventional block. However, the power-farming block, with increased plant density, showed 28% lower yields, with a processing rate that was 22% lower than that of the conventional block. Power tiller 2, which has crawler-type wheels, has a longer tread than power tiller 1. Because of this, power tiller 2 was found to be more useful, maintaining a stable center of gravity on slopes of up to 30 degrees. The power-farming block showed a reduced workload on farmers : The workload was only 92% of that of the conventional block, which the reduction rate was greater than that on non-sloped fields. Working postures required for the power-farming block were 100% at AC1, which required no improvement of working posture. Farmers who participated in the study found the new power tiller to be as useful and as comfortable as the conventional power tiller. However, from the standpoint of work safety, both power-farming and conventional methods should be used in combination.View full abstractDownload PDF (529K)
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