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Volume 44 (2009)
- Issue 4 Pages 185-
- Issue 3 Pages 127-
- Issue 2 Pages 65-
- Issue 1 Pages 1-
Volume 44, Issue 2
Displaying 1-3 of 3 articles from this issue
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Original Papers
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Hiroyuki FUJITA, Toshio FUKUI, Yoshinori KUNIMOTO2009 Volume 44 Issue 2 Pages 65-72
Published: June 20, 2009
Released on J-STAGE: December 20, 2009
JOURNAL FREE ACCESSTo mitigate problems occurring from the use of simple net fences, we examined the effectiveness of an improved net fence in preventing monkey invasion of agricultural fields surrounded by such fences and eliminating the resultant agricultural damage. A monitoring camera, on-site research, and interviews verified the monkeys' appearance, behavior, and agricultural damage.
The simple net fence's durability was improved by substituting the easily deteriorated nylon net material with polyethylene. Furthermore, covering the lower part of the fence to keep monkeys from viewing agricultural fields further enhanced the fence's performance in preventing monkey invasion and consequent damage.
Although a double-mesh version, elaborated from a simple fence to ward off more experienced monkeys, had previously been developed, it was found to be less effectual. In contrast, a simple electrified net fence—the original version combined with electrical deterrents—completely stopped monkey invasions, and no agricultural damage occurred.
Nonetheless, psychological barriers to monkeys, such as agricultural workers frightening them off, were also thought necessary to maintain the overall effectiveness of invasion-prevention fencing.View full abstractDownload PDF (906K) -
Koichiro FUKAMI, Mitsuho SUGIMOTO, Yoshiaki SHINZATO, Tohru AKACHI2009 Volume 44 Issue 2 Pages 73-80
Published: June 20, 2009
Released on J-STAGE: December 20, 2009
JOURNAL FREE ACCESSTo increase the number of days for which an agricultural machine in sugarcane filed of Jahgaru soil, which is heavy clay soil found in Okinawa, we developed a simple field drainage improvement technique that included subsoil breaking and drainage pit creation. Next, we determined the effects of this technique by setting the limit working conditions for the machines ; these conditions were derived from field experiments. The limit working condition for sugarcane cultivation, excluding harvesting conditions, was soil water content of ≥ 30%. When the total rain value was ≥50mm, the number of days for which a machine could function was 4 days more than that in a conventional setting. On the basis of these results, the area covered by the machine increased by approximately 4 and 5ha in the planter at summer planting and the hiller at spring and root planting respectively. The cost incurred for creating the drainage pit was approximately 37,000Yen. However, if the renewal timing considered as once every 4 years, then the cost averages to approximately 9,000Yen.View full abstractDownload PDF (794K)
Research Paper
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Daisuke MIYAMA, Katsuyuki YOSHIDA, Yasushi SATO, Osamu SUMIKAWA, Takuy ...2009 Volume 44 Issue 2 Pages 81-88
Published: June 20, 2009
Released on J-STAGE: December 20, 2009
JOURNAL FREE ACCESSAn insect-trapping machine with a blowing apparatus, which uses mist air flow to blow off and trap insects on tea plants, has been developed as a physical pest control method used in tea cultivation. This technology has been shown to be effective for controlling pests and may enable pesticide-free tea cultivation. We examined the effect of treatment with this insect-trapping machine on tea pests, tea yield, and the quality of the second tea crop by using plots treated once a week, those treated twice a week, untreated plots, and chemically treated plots. During the growth period of the second tea crop, twice-weekly treatment with the insect-trapping machine was found to be effective for the reducing in the number of tea green leafhoppers. In contrast, once-weekly treatment had no effect on the number of leafhoppers. Moreover, both once-weekly and twice-weekly treatments had no effect on the incidence of yellow tea thrips. The yield was greater in the plot that was treated twice-weekly than in the plot that was treated once-weekly and was approximately equal to that in the chemically treated plot. The scores of sensory tests on tea manufactured from the plot that was treated twice-weekly were higher than those in the case of the plot treated once-weekly and approximately equal to those in the case of the chemically treated plot. On the basis of these results, we conclude that twice-weekly treatment with the insect-trapping machine is recommended for maintaining the yield and quality of tea obtained using pesticide-free cultivation.View full abstractDownload PDF (741K)
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