2006 Fiscal Year Final Research Report Summary
Study on the agricultural land improvement for symbiosis with lives
| Project/Area Number |
16380157
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| Research Category |
Grant-in-Aid for Scientific Research (B)
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| Allocation Type | Single-year Grants |
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| Section | 一般 |
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| Research Field |
Irrigation, drainage and rural engineering/Rural planning
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| Research Institution | Niigata University |
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Principal Investigator |
MISAWA Shinichi Niigata University, Institute of Science and Technology, professor, 自然科学系, 教授 (30018791)
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| Co-Investigator(Kenkyū-buntansha) |
ARITA Hiroyuki Niigata University, Institute of Science and Technology, professor, 自然科学系, 教授 (40313506)
OHKUBO Hiroshi Yamagata University, Faculty of Agriculture, professor, 農学部, 教授 (80203735)
KONDOH Tadashi Akita Prefectural University, Faculty of biology and resources science, associate professor, 生物資源科学部, 助教授 (70279503)
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| Project Period (FY) |
2004 – 2006
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| Keywords | paddy field / lives / symbiosis / Japanese crested ibis / loach / water quality / catchment canal / environment preservation agriculture |
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| Research Abstract |
In this study, authors have examined the inhabiting environment of loaches, the primary diet for crested ibis (Nipponia nippon) that is to be reintroduced into the wild in 2008. In the course of the examination, we have attempted to comprehend the distribution and abundance of loaches in agricultural canals and paddy fields. According to our survey, the following observations and findings have been noted: 1. A large number of loaches exits even in the sloped streams with waterfalls and drop works of the study area. Those loaches are supplied from upper swampy terraced paddy fields, and stay in stream sections with baskets of stones or piers of log. These structures create pools of deep, slow-velocity water where loaches can find refuge when floods occur. The effect of baskets of stones was verified in an experiment. 2. With regard to paddy field structure, loaches show a strong preference to paddy field with catchment ditches, commonly found in Sado Island. Upon this finding, authors h
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ave proposed to make catchment ditches with 50cm width and 30cm depth beside upper paddy fields in terraced paddy areas. 3. Loaches and other species are unable to leap over gaps between outlets of paddy fields and drainage canals created as a result of land improvement constructions. Generally, the elevation gap is designed to be at least lm for facilitating the gravity drainage of undrerdrainage systems. To reduce the elevation gap, authors suggested embedding perforated catch pipe separately when land improvement construction would be undertaken. 4. Authors also proposed to use corrugated tube as a fishway bridging the gap between paddy field and drainage canal for the areas where land improvement had already completed. Due to its flexibility, corrugated tubes present significant application and cost advantages. In the laboratory experiment, it has been proven that loaches are able to migrate with extremely small discharge.
Furthermore, authors have presented the necessary conditions of paddy field in the case of bio-friendly deep ponding water cultivation, and the influence of nutrient salts used as fertilizer by various cultivation methods on Hachirogata district. Less
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Research Products
(4 results)
